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CDHO Advisory: Gastrointestinal Tract Tumours









Use of the dental hygiene interventions of scaling of teeth and root planing including curetting surrounding tissue, orthodontic and restorative practices, and other invasive interventions for persons with  gastrointestinal tract tumours.


Cite as College of Dental Hygienists of Ontario, CDHO Advisory Gastrointestinal Tract Tumours, 2020-01-20


Scaling of teeth and root planing including curetting surrounding tissue, orthodontic and restorative practices, and other invasive interventions (“the Procedures”).



Gastrointestinal tract tumours


Advanced practice nurses
Dental assistants
Dental hygienists
Health professional students
Public health departments
Regulatory bodies


To guide dental hygienists at the point of care relative to the use of the Procedures for persons who have gastrointestinal tract tumours, chiefly as follows.

  1. Understanding the medical condition.
  2. Sourcing medications information.
  3. Taking the medical and medications history.
  4. Identifying and contacting the most appropriate healthcare provider(s) for medical advice.
  5. Understanding and taking appropriate precautions prior to and during the Procedures proposed.
  6. Deciding when and when not to proceed with the Procedures proposed.
  7. Dealing with adverse events arising during the Procedures.
  8. Keeping records.
  9. Advising the patient/client.


Child (2 to 12 years)
Adolescent (13 to 18 years)
Adult (19 to 44 years)
Middle Age (45 to 64 years)
Aged (65 to 79 years)
Aged 80 and over
Parents, guardians, and family caregivers of children, young persons and adults with gastrointestinal tract tumours.


For persons who have gastrointestinal tract tumours: to maximize health benefits and minimize adverse effects by promoting the performance of the Procedures at the right time with the appropriate precautions, and by discouraging the performance of the Procedures at the wrong time or in the absence of appropriate precautions.



Types of gastrointestinal tract tumours covered in the Advisory

  1. Anal cancer
  2. Colorectal cancer
  3. Esophageal tumours
  4. Inherited colorectal cancer syndromes
  5. Pancreatic cancer
  6. Pancreatic endocrine tumours
  7. Polyps of the colon and rectum
  8. Small-bowel tumours
  9. Stomach cancer
  10. Tumours of the mouth and adjacent tissues
    1. Jaw tumours
    2. Oral squamous cell carcinoma
    3. Salivary gland tumours

Terminology used in this Advisory

  1. Achalasia, a disorder of the esophagus which
    1. impairs its ability to move food to the stomach
    2. originates in damage to the nerves of the esophagus 
  2. Adenocarcinoma, a malignant tumour in epithelial tissue, specifically in a gland.
  3. Adenoma, a benign tumour that 
    1. develops from epithelial tissue 
    2. in the colon is often referred to as an adenomatous polyp, which occur in a range of sizes
    3. is not cancerous, though some adenomas have the potential to become cancerous.
  4. Ameloblastoma (adamantinoma), a benign tumour, which usually is
    1. in the posterior regions of the mandible
    2. composed of epithelial cells that resemble enamel-producing cells but do not form enamel. 
  5. Anatomy of the gastrointestinal tract and its terminology are illustrated in the diagram:
    1. Digestive system
  6. Benign and malignant
    1. benign refers to a tumour that
      1. is not cancerous
      2. does not spread within the body
      3. usually grows slowly
      4. which is often but not always harmless because of pressure on adjacent
        1. blood vessels
        2. nerves
        3. organs
    2. malignant refers to cancerous cells that 
      1. spread throughout the body, by metastasis, invading or destroying tissues 
      2. grow rapidly in an uncontrolled way
      3. may 
        1. be resistant to treatment
        2. return even after all have been removed or destroyed.
  7. arcinoma, a malignant tumour that starts in epithelial tissue.
  8. Cystadenocarcinoma of the pancreas, a rare type of pancreatic cancer that develops from a cystadenoma, a benign tumour. 
  9. Ductal adenocarcinoma, Adenocarcinoma that arises in the duct of the pancreas.
  10. Dysphagia, difficulty swallowing.
  11. Epithelial tissue, a tissue which
    1. is a layer of cells that
      1. covers  the body
      2. lines all the body’s cavities except blood  vessels and lymphatics 
    2. is of two principal types from both of which colorectal cancer develops
      1. lining epithelial tissue
      2. glandular epithelial tissue.
  12. Erythroplakia and leukoplakia
    1. may be regarded as pre-cancerous conditions
    2. erythroplakia is a slightly raised red area in the mouth that bleeds easily 
    3. leukoplakia causes white patches in the mouth.
  13. Gardner syndrome, which 
    1. is characterized by multiple osteomas
    2. requires early identification, which is clinically critical, because
      1. of the multiple gastrointestinal polyps which invariably become malignant
      2. more than half the patients with Gardner syndrome have dental
        anomalies, which may first be detected during oral health investigations for multiple

        1. impacted teeth
        2. un-erupted teeth.
  14. Helicobacter pylori, a bacterium which 
    1. is commonly found in the stomach
    2. is present in approximately one-half of the world’s population
    3. in most people it infects, produces
      1. no symptoms
      2. no problems attributable to it
    4. is capable of causing  digestive problems, such as
      1. ulcers
      2. much less commonly, stomach cancer. 
  15. Metastasis
    1. the process by which tumour cells 
      1. move from the primary location of a cancer
      2. sever connections with the original cell group
      3. establish remote colonies
    2. a tumour that develops away from the site of origin. 
  16. Odontoma, a type of tooth tumour that 
    1. interferes with eruption of teeth
    2. is usually asymptomatic
    3. occurs usually before the age of 20 years
    4. occupies the space of a missing tooth or represents a developmental defect of a supernumerary tooth
    5. contains enamel, dentin, or cementum 
    6. includes fibrous odontoma, an odontoma containing fibrous elements, and cementoma
    7. may be suggested by a clinically absent tooth, separated teeth or an expanded jaw 
    8. is generally noted on radiographic examination
  17. Oral exostoses, tori, that
    1. are bony swellings in the mouth
    2. are not rare 
    3. vary in shape and size
    4. occur 
      1. in the midline of the palate
      2. on the lingual side of the lower jaw 
      3. on the buccal side of upper and lower jaws
    5. are regarded as developmental abnormalities that may
      1. present in adult life
      2. grow slowly throughout life.
  18. Oral human papillomavirus comprises a group of viruses 
    1. with more than 100 types; of these at least 40 can be passed through sexual contact
    2. that often produce asymptomatic infections which resolve without treatment. 
  19. Osteoma, a benign bony outgrowth that 
    1. occurs mostly on skull and facial bones
    2. may occur in Gardner syndrome.
  20. Osteosarcoma 
    1. is the most common cancerous bone tumour in youth
    2. is diagnosed at the average age of 15
    3. may rarely occur in adults 
    4. appears equally frequently in boys and girls until late adolescence, when boys are more commonly affected. 
  21. Proton pump inhibitors, medications that 
    1. are used to treat some gastrointestinal disorders
    2. reduce the amount of acid in the stomach.
  22. Squamous cells, the flat, skin-like cells that cover the inside of the mouth, nose, larynx and throat.
  23. Squamous cell carcinoma, squamous cell cancer 
    1. is carcinoma of squamous cells
    2. accounts for 90 percent of mouth and oropharyngeal cancers.

Overview of gastrointestinal tract tumours

Resources consulted

  1. Anal cancer
    1. develops in the anal canal, where it occurs as squamous cell carcinoma
    2. in Canada accounts for less than 1 percent of all cancers
    3. has causes and risk factors
      1. commonly associated with the human papilloma virus which causes warts
        1. in and around the anus of men and women
        2. on the cervix in women, with increased risk of cervical cancer 
      2. that also include risk factors such as
        1. age 50 years or above
        2. anal sex
        3. smoking
        4. immunosuppression (CDHO Advisory)
        5. chronic anal-area inflammation
        6. radiation therapy (CDHO Advisory) for pelvic-area cancer 
    4. produces signs and symptoms that include
      1. bleeding from the rectum or anus
      2. the sensation of a lump or mass at the anal opening
      3. pain in the anal area
      4. persistent or recurrent itching
      5. change in bowel habits, more or less bowel movements, or increased straining during a bowel movement
      6. narrowing of the stools
      7. discharge of mucus or pus from the anus
      8. swollen lymph nodes in the anal or groin areas
    5. is medically investigated by biopsy
    6. is treated  with surgery
      1. augmented if required by
        1. chemotherapy (CDHO Advisory)
        2. radiation therapy (CDHO Advisory)
    7. lacks clear means of prevention  because of uncertainty whether early recognition and eradication improve long-term outcomes, though preventive advice commonly includes
      1. avoiding anal sex 
      2. avoiding infection with 
        1. human papilloma virus
        2. human immunodeficiency virus (CDHO Advisory)
      3. stopping smoking 
    8. has a good prognosis that reflects the high degree of effectiveness of treatment.
  2. Colorectal cancer
    1. develops
      1. in the rectum and sigmoid in 70 percent of instances
      2. as adenocarcinomas in 95 percent of instances, which most commonly develop from adenomas
      3. slowly, and may have been developing for years prior to diagnosis
      4. as  cancer of the colon, more commonly among women
      5. as cancer of the rectum, more commonly among men
      6. at more than one site in 5 percent of patients
    2. occurs
      1. very commonly
        1. in Western countries, in which the colon and rectum account for more new cases of cancer per year than any anatomical site except the lung (and in Canada, as of 2019, also the breast)
        2. accounts for an estimated 26,300 cases and 9,600 deaths in Canada annually  
        3. accounts for an estimated 135,430 cases and 50,260 deaths in the US annually
      2. increasingly after age 40 and peaks at age 60 to 75
      3. in Canada since 1997 with declining trends in mortality rates, likely due to improvements in treatment, such as chemotherapy (CDHO Advisory), and earlier detection via screening programs
        1. -1.5 percent per year in men
        2. -1.8 percent  per year in women
    3. has causes and risk factors that may be
      1. associated with malignant transformation of adenomatous polyps,  which in
        1. 80 percent of instances occur as isolated instances
        2. 20 percent of instances have an inherited component
      2. associated with the duration of two important predisposing conditions
        1. chronic ulcerative colitis (CDHO Advisory)  
        2. Crohn’s disease (CDHO Advisory)  
      3. associated with low-fibre diets that are high in animal protein, fat, and refined carbohydrates, and possibly also associated with carcinogens that
        1. may be ingested in the diet 
        2. or are produced by bacterial action on dietary substances or biliary or intestinal secretions
    4. produces signs and symptoms that
      1. depend on the tumour’s
        1. location
        2. type
        3. extent
        4. complications
      2. chiefly include 
        1. blood in the stool from bleeding
          1. that is 
            1. usually occult, that is, it cannot be seen with the naked eye
            2. may occur with defecation
            3. may be accompanied by 
              1. straining
              2. pain
          2. may be sufficient to cause severe anemia (CDHO Advisory) which results in
            1. fatigue 
            2. weakness
        2. change in bowel habits, such as
          1. constipation alternating with increased stool frequency
          2. diarrhea
        3. colicky abdominal pain
        4. abdominal emergency, such as perforation
      3. may manifest 
        1. only when the colorectal adenocarcinoma has grown enough to cause symptoms, which may take years
        2. first with symptoms and signs of metastatic spread, such as enlargement of the supraclavicular lymph nodes 
    5. is medically investigated by
      1. fecal immunochemical test (FIT) for screening2 
        1. which enable some colorectal cancer to be detected at an earlier stage, which improves prospects for cure 
        2. for averagerisk persons should be done every 2 years between ages 50 and 74 years (as per Cancer Care Ontario [CCO], 2020)
        3. which may be replaced by flexible sigmoidoscopy  every 10 years for average-risk persons between ages 50 and 74 years
        4. which should be replaced by colonoscopy for persons at elevated risk (including family history of colorectal cancer) beginning at age 50 years or 10 years earlier than first-degree relative was diagnosed
      2. colonoscopy with biopsy or excising of tumours following positive fecal occult blood screening 
    6. is treated 
      1. by surgical removal
      2. for involvement of lymph nodes by
        1. chemotherapy (CDHO Advisory) with particular types of medications
        2. radiation therapy (CDHO Advisory)
      3. postoperatively with follow-up for recurrence with 
        1. routine colonoscopy 
        2. physical examinations and laboratory tests
      4. by palliation when curative surgery is
        1. not possible 
        2. not an acceptable risk
      5. with medications
    7. is prevented by
      1. early detection with screening through organized programs for
        1. identification and removal of pre-cancerous polyps
        2. fecal occult blood testing
      2. aspirin and NSAIDs
    8. has a prognosis that depends greatly on the stage of the cancer; the 10-year survival rate for cancer
      1. limited to the mucosa approaches 90 percent
      2. with extension through the bowel wall is 70 to 80 percent
      3. with lymph node involvement is 30 to 50 percent
      4. with metastatic disease is less than 20 percent.
  3. Inherited colorectal cancer syndromes is an inherited predisposition to colorectal cancer, which occurs in 5 to 10 percent of persons with colorectal cancer, and that includes familial adenomatous polyposis, a hereditary disorder that 
    1. causes numerous polyps in the colon
    2. results in colon cancer by age 40
    3. is usually asymptomatic but may be marked by rectal bleeding, which typically is occult
    4. is diagnosed by 
      1. colonoscopy
      2. genetic testing
    5. is treated by 
      1. colectomy 
      2. medications
    6. is followed up by 
      1. routine upper endoscopy 
      2. annual physical examination of the thyroid
    7. is diagnosed with a combination of the
      1. family history
      2. person’s medical history
      3. clinical findings
  4. Esophageal tumours
    1. exist as many types of benign esophageal tumours, but most are of little consequence except  when they cause
      1. dysphagia
      2. ulceration or bleeding, which is rare
    2. occur as malignant esophageal tumours
      1. in the two thirds of the esophagus closest to the mouth, most commonly as squamous cell carcinoma, which
        1. worldwide
          1. accounts for the majority of all esophageal cancers
          2. is among the most deadly cancers
          3. ranks among the 10 most frequent
        2. in Canada has among the lowest survival rates of all cancers
        3. in recent years has shown a decline in various Western countries
        4. in the US, is 
          1. 4 to 5 times more common among blacks than whites
          2. 2 to 3 times more common among men than women
      2. in the one third of the esophagus closest to the stomach, most commonly is adenocarcinoma, which has shown a rise in the frequency in various Western countries, as well as in Ontario (where it is the most common type of esophageal cancer)
      3. infrequently as metastatic cancer, which 
        1. constitutes 3 percent of esophageal cancer
        2. is most likely to originate with melanoma and breast cancer, but may also arise with cancers at other common sites 
    3. have causes and risk factors for 
      1. squamous cell carcinoma that 
        1. primarily include
          1. alcohol ingestion (CDHO Advisory) 
          2. tobacco use, in any form
        2. also include 
          1. achalasia
          2. human papillomavirus
          3. Plummer-Vinson syndrome
          4. radiation therapy (CDHO Advisory)
          5. esophageal webs, a structural abnormality
        3. may also include genetic causes
      2. adenocarcinoma, which is associated with obesity and can arise from Barrett’s esophagus which results from
        1. chronic gastroesophageal reflux disease (CDHO Advisory) and reflux esophagitis
        2. changes to the part of the esophagus closest to the stomach when healing of acute esophagitis takes place the presence of stomach acid
    4. produce signs and symptoms that 
      1. tend not to appear in the early stage 
      2. include
        1. dysphagia, which progresses from difficulty swallowing solid food to difficulty swallowing fluid and even saliva
        2. weight loss
        3. anemia
        4. cough
        5. stools blackened by blood from internal hemorrhage
      3. may include
        1. chest pain, usually radiating to the back
        2. hiccups
        3. spread to lymph nodes such as 
          1. cervical
          2. supraclavicular
    5. are medically investigated by
      1. endoscopy with biopsy
      2. CT and endoscopic ultrasound
      3. basic blood tests
    6. are treated  
      1. based on assessments of the tumour
      2. according to the person’s wishes
      3. with surgery often combined with 
        1. chemotherapy (CDHO Advisory)
        2. radiation therapy (CDHO Advisory)
      4. by post-operative screening for recurrence
      5. by palliation for persons
        1. unable or unwilling to undergo surgery 
        2. with the most advanced stage, for whom surgery is contraindicated
      6. with medications
    7. lack effective means of prevention because so many persons present with advanced disease
    8. have a prognosis that 
      1. depends greatly on stage
      2. overall is poor with a 5-year survival less than 5 percent because 
        1. many patients present with advanced disease
        2. cancers of the esophagus are among the most deadly of all gastrointestinal malignancies
    9. present significant social considerations that involve
      1. palliation directed at 
        1. reducing esophageal obstruction sufficiently to allow oral intake
        2. relieving significant suffering caused by esophageal obstruction by means of salivation and recurrent aspiration by procedures that include 
          1. manual dilation procedures
          2. orally inserted stents
          3. radiation therapy (CDHO Advisory)
          4. cervical esophagostomy with feeding jejunostomy
      2. supportive care, including nutritional support
        1. by parenteral supplementation 
        2. endoscopically or surgically placed feeding tube
      3. end-of-life care, which should always 
        1. aim to control
          1. pain 
          2. problems associated with inability to swallow secretions
        2. provide advice to persons to 
          1. make end-of-life care decisions early in the course of disease 
          2. record their wishes in an advance directive.
  5. Pancreatic cancer
    1. occurs in the pancreas
      1. chiefly ductal adenocarcinoma, which has a poor prognosis 
      2. rarely  cystadenocarcinoma, which has a relatively good prognosis
    2. as ductal adenocarcinoma 
      1. in the US accounts for an estimated 37,000 cases and 33,000 deaths annually
      2. in Canada has among the lowest survival rates of all cancers
      3. occurs
        1. at the mean age of 55 years 
        2. 1.5 to 2 times more often in men
      4. has causes and risk factors that include
        1. smoking
        2. history of chronic pancreatitis
        3. possibly 
          1. long-standing diabetes mellitus, primarily in women
          2. heredity
      5. exhibits signs and symptoms that
        1. occur late so that, by the time of diagnosis, 90 percent of persons have locally advanced tumours that have spread
        2. include 
          1. severe upper abdominal pain, which usually radiates to the back 
          2. weight loss 
          3. jaundice, often causing pruritus, in 80 to 90 percent of patients
          4. gastrointestinal hemorrhage
          5. diabetes in 25 to 50 percent of patients, leading to symptoms of glucose intolerance, such as
            1. frequent urination
            2. excessive thirst
      6. is medically investigated with
        1. CT or other scans 
        2. CA 19-9 antigen test 
        3. routine laboratory tests for bile duct obstruction or liver metastases
      7. is treated with 
        1. the Whipple procedure
        2. adjuvant chemotherapy (CDHO Advisory) and radiation therapy (CDHO Advisory)
        3. adjuvant medication
      8. lacks clear and well established methods of prevention according to the US Preventive Services Task Force (USPSTF) in its Final Recommendation Statement on Pancreatic Cancer Screening (2019), which noted that 
        1. the USPSTF found no evidence for benefit of screening for pancreatic cancer in the general population by any method
      9. has a prognosis that 
        1. varies with the stage of the pancreatic cancer
        2. is poor overall, with a 5-year survival that is less than 2 percent, because so many persons with pancreatic cancer have advanced disease, such as metastasis or invasion of major blood vessels, at the time of diagnosis  
      10. presents significant social considerations that arise because
        1. some 80 percent to 90 percent of pancreatic cancers
          1. are considered surgically incurable at time of diagnosis 
          2. require surgery directed at relieving obstruction, a temporary treatment
        2. most patients experience pain and die, and require 
          1. symptomatic treatment, which is as important as attempts at controlling the disease
          2. appropriate end-of-life care that is acceptable to the person and the person’s family.
  6. Pancreatic endocrine tumours
    1. comprise
      1. functional tumours, which
        1. are the most common type of pancreatic endocrine tumours
        2. secrete one or more hormones into the blood, which leads to
          1. raised blood levels
          2. recognizable clinical signs and symptoms
      2. nonfunctional tumours, which are not associated with raised blood levels of hormones
    2. have a prognosis that
      1. is largely determined by 
        1. the type of tumour
        2. rate of tumour growth
        3. metastasis
      2. depends on the success of surgery especially with the non-malignant types. 
  7. Polyps of the colon and rectum
    1. consist of a mass of tissue that 
      1. arises from the bowel wall 
      2. protrudes into the bowel
      3. varies considerably in size
    2. are of two forms
      1. sessile
      2. pedunculated
    3. are chiefly of two types
      1. adenomatous polyps, which
        1. are of great concern because of their risk of becoming cancerous
        2. may when numerous be familial adenomatous polyposis
      2. nonadenomatous polyps, which
        1. do not become cancerous 
        2. may result in uncontrollable bleeding for which treatment is required
        3. occur in 
          1. chronic ulcerative colitis (CDHO Advisory)  
          2. Crohn’s disease (CDHO Advisory)  
          3. children as juvenile polyps, which normally disappear after puberty
    4. in incidence range from 7 percent to 50 percent
    5. occur most commonly in the rectum and the part of the large intestine that is closest to the rectum 
    6. are present in some 25 percent of patients with cancer of the large bowel 
    7. though are mostly asymptomatic, may be associated with signs and symptoms that include
      1. rectal bleeding, usually occult and rarely massive, as the most frequent complaint
      2. cramps, abdominal pain, or obstruction that may occur with large polyps
      3. an occasional polyp with a long pedicle that prolapses through the anus
      4. watery diarrhea caused by large adenomas 
    8. are medically investigated by colonoscopy, during which
      1. polyps may be removed
      2. cancer screened is conducted
    9. are treated by
      1. complete removal during colonoscopy using a snare or biopsy techniques
      2. surgery for 
        1. excision of large polyps
        2. removal of cancer
      3. follow-up surveillance colonoscopy
    10. are prevented by 
      1. surveillance for patients with colorectal polyps
      2. medications.
  8. Small-bowel tumours
    1. are rare
    2. are distributed as follows
      1. duodenum, 50 percent 
      2. jejunum, 30 percent
      3. ileum,  20 percent 
    3. account for 1 to 5 percent of gastrointestinal tumours 
    4. increase in occurrence with age
    5. consist of
      1. benign tumours, which all may cause abdominal distention, pain, bleeding, diarrhea, and, if obstruction develops, vomiting
      2. adenocarcinoma, the most common type, which usually
        1. arises in the duodenum or jejunum
        2. causes few symptoms
        3. occurs in Crohn’s disease (CDHO Advisory)  
      3. primary malignant lymphoma (CDHO Advisory
      4. carcinoid tumours, which 
        1. occur most often in the small bowel, particularly the ileum and the appendix, and in these locations are often malignant
        2. in about 30 percent of small-bowel instances cause obstruction, pain, bleeding, or carcinoid syndrome
        3. are treated with surgery
      5. Kaposi’s sarcoma, which 
        1. was first described as a disease of elderly Jewish and Italian men
        2. occurs in an aggressive form in 
          1. Africans
          2. transplant recipients
          3. persons with HIV/AIDS (CDHO Advisory), in whom it is common
        3. may arise anywhere in the gastrointestinal tract 
          1. but most commonly in the small bowel, colon or stomach
          2. is usually asymptomatic, though it may be marked by
            1. bleeding
            2. diarrhea
            3. protein-losing enteropathy
        4. may be associated with a second primary intestinal cancer, which 
          1. occurs in some 20 percent of patients
          2. most often is 
            1. lymphocytic leukemia (CDHO Advisory)
            2. non-Hodgkin lymphoma (CDHO Advisory)
            3. Hodgkin lymphoma (CDHO Advisory)
            4. adenocarcinoma of the  gastrointestinal tract. 
    6. are diagnosed by
      1. fluoroscopic X-ray of the small intestine
      2. endoscopy which reaches further into the small intestine than the standard procedure
      3. capsule video endoscopy, in which a pill-sized video camera
        1. is swallowed
        2. takes images of the small intestine as it passes through
        3. transmits the images to a recording device worn by the person
    7. may have as risk factors 
      1. smoking
      2. alcohol abuse
      3. diets high in fat and sugar
    8. is treated by 
      1. surgery
      2. enteroscopy, during which procedures such as electrocautery, thermal obliteration, or laser phototherapy are performed.
  9. Stomach cancer
    1. is the second most common cancer worldwide
    2. varies widely in incidence, which is high in Japan, China, Chile, and Iceland
    3. in Canada and the US
      1. incidence has declined in recent decades and number of deaths has decreased to the 11th most common cause of death from cancer in Canada
      2. accounts for an estimated 4,100 new cases and 1,950 deaths in Canada annually 
      3. accounts for an estimated 27,600 new cases and 11,010 deaths in the US annually
    4. occurs 
      1. as gastric adenocarcinoma, which accounts for 95 percent of malignant tumours of the stomach
      2. less commonly as 
        1. localized gastric lymphomas (CDHO Advisory)
        2. leiomyosarcomas
      3. in the US 
        1. most commonly among
          1. Blacks
          2. Hispanics
          3. American Indians
        2. where more than 75 percent of persons diagnosed are 50 years or older
      4. in Canada with incidence rates that are declining
        1. -1.9 percent per year in males (1984–2015 average annual percent change [APC])
        2. -1.9 percent per year in females (1984–2015 APC)
    5. is caused by or is associated with
      1. Helicobacter pylori infection, which is the cause of most stomach cancer
      2. tobacco use
      3. gastric polyps, which 
        1. of adenomatous type may be precursors of cancer
        2. may be associated with medications, such as
          1. NSAIDs
          2. proton pump inhibitors
    6. has risk factors that 
      1. include autoimmune atrophic gastritis 
      2. involve various genetic factors 
      3. do not involve dietary factors 
    7. produces signs and symptoms that 
      1. initially are nonspecific, often presenting as dyspepsia suggestive of peptic ulcer
      2. tend to be dismissed as acid-related disorders, such as dyspepsia
      3. later include fullness after ingestion of small amounts of food, indicative of obstruction by the cancer
      4. may include 
        1. dysphagia if cancer in the cardiac region of the stomach obstructs the esophageal outlet
        2. loss of weight or strength, usually resulting from dietary restriction
        3. secondary anemia, which may follow loss of blood in the feces
        4. late-stage involvement of the left supraclavicular lymph nodes
      5. occasionally first presents as the symptoms and signs of metastasis, such as
        1. accumulation of fluid in the peritoneal cavity
        2. fractures
        3. jaundice
    8. is medically investigated, for a differential diagnosis that commonly includes peptic ulcer and its complications, with
      1. endoscopy and biopsy
      2. CT and endoscopic ultrasound
      3. basic blood tests to assess anemia, hydration, general condition, and possible liver metastases 
    9. is treated 
      1. according to 
        1. assessments of the tumour
        2. the person’s wishes
      2. with surgery sometimes combined with 
        1. chemotherapy (CDHO Advisory)
        2. radiation therapy (CDHO Advisory)
      3. medications
    10. lacks clearly established preventive procedures 
      1. other than follow-up post-operative screening for recurrence
      2. though the decline in Canadian incidence may be due to
        1. changes in diet
        2. decreases in smoking and heavy alcohol use
        3. increased recognition and treatment of infection with the bacterium Helicobacter pylori 
    11. has a prognosis that 
      1. depends greatly on the cancer’s stage 
      2. overall is poor, with a 5-year survival of less than 5 percent to 15 percent because most patients present with advanced disease
      3. has a 5-year survival as high as 80 percent if the tumour is limited to the mucosa or submucosa
      4. has a 5-year survival of 20 percent to 40 percent when local lymph nodes are involved
      5. has a survival of 1 year or less when the cancer is widespread
    12. presents significant social considerations that 
      1. involve the patient’s wishes, which may require advance directives
      2. reflect the challenges that 
        1. curative surgery 
          1. involves removal of most or all of the stomach and adjacent lymph nodes
          2. is indicated only in persons with disease limited to the stomach and perhaps the regional lymph nodes, which represents less than 50 percent of patients 
        2. adjuvant or combined chemotherapy (CDHO Advisory) and radiation therapy (CDHO Advisory) after surgery may be beneficial 
          1. only if the tumour is removable
          2. but may improve the median survival only by about six months
        3. metastasis or extensive nodal involvement 
          1. contraindicates curative surgery
          2. indicates palliative procedures, such as palliative surgery which
            1. typically consists of a gastroenterostomy to bypass a pyloric obstruction
            2. is performed only if quality of life can be improved
          3. may not be fully recognized until curative surgery is attempted. 
  10. Tumours of the mouth and adjacent tissues
    1. include cancers of
      1. lip (CDHO Advisory)
      2. mouth (CDHO Advisory)
      3. salivary gland
      4. tongue (CDHO Advisory)
      5. larynx, which 
        1. are squamous cell carcinomas
        2. are the most common non-cutaneous tumours of the head and neck, followed by squamous cell carcinomas of
          1. the tongue
          2. palatine tonsil
          3. floor of the mouth
    2. in Canada occur with overall declining incidence (between 1984 and 2015) and mortality in men and women (between 1984 and 2015), trends attributed to
      1. decline in smoking
      2. decreases in heavy alcohol use
    3. occur as oral cavity cancer with increasing incidence in Canada in persons younger than 40 years of age, likely due to changing risk factors (e.g., oral human papillomavirus infection)
    4. as jaw tumours 
      1. occur in benign and malignant forms
        1. most commonly as squamous cell carcinoma which invades the bone through dental sockets in the mandible and maxilla 
        2. as ameloblastoma, the most common epithelial odontogenic tumour, which
          1. usually arises in the posterior mandible
          2. is slowly invasive and rarely metastatic
        3. as odontoma, the most common odontogenic tumour, which
          1. affects the dental follicle or the dental tissues
          2. usually appears in the mandibles of young people 
        4. as osteosarcoma which, along with other rare malignant tumours, may affect the jaw
      2. create signs and symptoms chiefly located to
        1. bone, as
          1. pain, which may be severe
          2. tenderness
          3. oral exostoses of the
            1. mandible
            2. palate, on which they 
              1. are in the midline
              2. have intact, smooth mucosa
          4. osteoma, which may suggest Gardner syndrome when
            1. multiple
            2. detected during oral healthcare inspection
        2. swelling of the
          1. alveolar ridge
          2. face
          3. palate
        3. unexplained tooth mobility 
      3. may be discovered with routine
        1. inspections of the oral cavity and teeth
        2. dental x-rays
      4. are diagnosed  and treated according to type, such that
        1. some benign tumours may not require surgical excision unless they interfere with
          1. oral healthcare or oral self-care
          2. submandibular gland function
          3. integrity of surrounding bone 
        2. malignant and some benign tumours require surgical removal and reconstruction
    5. as oral squamous cell carcinoma, which 
      1. in occurrence is
        1. the most common oral or pharyngeal cancer
        2. the most common cancer at head and neck sites in general
      2. as oral squamous cell cancer that
        1. affects about 33,000 North Americans each year
        2. in the US
          1. accounts for 
            1. 3 percent of cancers in men
            2. 2 percent in women 
          2. chiefly occurs after age 50
        3. occurs as squamous cell carcinoma of the tonsil which, among cancers of the upper respiratory tract, occurs 
          1. in frequency second only to carcinoma of the larynx
          2. occurs predominantly in males
        4. develops
          1. on the floor of the mouth or on the lateral and ventral surfaces of the tongue in 40 percent of instances 
          2. on the lower lip in 38 percent of instances, which are usually related to sun exposure
          3. in the palate and tonsillar area in 11 percent of instances
      3. has well defined risk factors, especially
        1. smoking
        2. alcohol use and abuse
        3. for the tongue, chronic irritation, which may arise with
          1. damaged or fractured teeth
          2. ill-fitting denture or dental appliances
          3. overuse of certain oral rinses
          4. chewing tobacco
          5. use of betel quid
      4. may also be associated with oral human papillomavirus, typically acquired via oral-genital contact
      5. has clinically significant presentations of symptoms and signs especially because the oral lesions
        1. are initially asymptomatic 
        2. may appear first as areas of erythroplakia or leukoplakia and may be 
          1. raised from the surface
          2. ulcerated
        3. after becoming cancerous 
          1. are often hardened and firm with a rolled border
          2. in the form of tonsillar carcinoma may manifest as
            1. an asymmetric swelling and sore throat
            2. pain radiating to the ear of the same side
            3. a mass in the neck
      6. is medically investigated with
        1. biopsy
        2. direct laryngoscopy, bronchoscopy, and esophagoscopy to detect a second primary cancer
        3. chest x-ray
        4. CT of head and neck
      7. is treated with
        1. surgery and radiation therapy (CDHO Advisory) as the treatments of choice
        2. speech and swallowing therapy, which may be required after significant surgery
        3. chemotherapy (CDHO Advisory), which may be used in palliative care when the cancer has spread to other organs
        4. laser instead of surgical excision to remove all mucosa affected by squamous cell carcinoma of the lip followed by
          1. reconstruction to maximize postoperative function
          2. sunscreen applications
        5. chemotherapy (CDHO Advisory) and radiation therapy (CDHO Advisory) for tonsillar carcinoma
      8. has prognoses for carcinoma of the
        1. tongue that is localized and has no lymph node involvement: 5-year survival greater than 50 percent
        2. floor of the mouth that
          1. is localized and has no lymph node metastasis: 5-year survival of 65 percent
          2. has lymph node metastasis: 5-year survival of 50 percent
        3. lower lip: 5-year survival of 90 percent, and rarely produces metastasis 
        4. upper lip: may be less favourable than for the lower lip because it is more aggressive and metastatic
        5. palate and tonsillar area: 5-year survival of
          1. 68 percent if treatment occurs prior to lymph node involvement 
          2. 17 percent if treatment occurs after lymph node involvement
      9. is prevented from developing into fatal disease by screening  
        1. for early detection of curable lesions, which are rarely symptomatic 
        2. which involves careful examination of the oral cavity and oropharynx during routine care
    6. as salivary gland tumours, which
      1. develop most commonly
        1. in the parotid glands, but may also occur in the
          1. submandibular 
          2. minor salivary glands
          3. sublingual salivary glands
        2. in benign form though
          1. benign forms may become malignant, though the change usually occurs only after the benign tumour has been present for 15 to 20 years 
          2. malignant forms do occur, and are
            1. characterized by 
              1. rapid growth 
              2. pain and neural involvement
            2. firm, nodular, and may be fixed to adjacent tissue, often with a poorly defined periphery
            3. eventually marked by 
              1. ulceration of the overlying skin 
              2. invasion of adjacent tissues
      2. are 
        1. of unknown cause
        2. without evident risk factors 
      3. produce signs and symptoms that 
        1. for benign and most malignant tumours typically manifest as a solitary mass beneath normal skin or mucosa, which is
          1. slow-growing
          2. movable
          3. painless
          4. usually firm though may be soft when cystic
        2. in nerve-invading malignant tumours manifest as
          1. localized or regional pain
          2. numbness
          3. tingling, pins and needles, or pricking
          4. burning pain, which may be intense
          5. loss of motor function
      4. are medically investigated with
        1. biopsy to confirm the cell type
        2. CT and MRI for extent of tumour or its spread
      5. are treated 
        1. by surgery for excision
        2. sometimes also with radiation therapy (CDHO Advisory)
      6. in the malignant forms have a prognosis that 
        1. varies between 95 percent and 50 percent 5-year survival rate, depending on type 
        2. in malignant transformation reflects a very low cure rate.

Multimedia and images

Comorbidity, complications and associated conditions

Comorbid conditions are those which co-exist with gastrointestinal tract tumours but which are not believed to be caused by them. Complications and associated conditions are those that may have some link with them. Distinguishing among comorbid conditions, complications and associated conditions may be difficult in clinical practice. 

Gastrointestinal tract tumours create challenges for oral healthcare because of the wide range of tumour types and because of the multiplicities of their comorbidities, complications and associated conditions, many of which are directly or indirectly linked with the mouth or its functions.

Particular challenges to which oral healthcare is especially relevant in connection with the escalating estimates of age-related cases of cancer are as follows:

  1. The number of aged persons with cancer is increasing as the population ages. 
  2. Colorectal cancer, in particular, is a very common cancer (accounting for 12% of all newly diagnosed non-melanoma skin cancer cases in Canada) and, of the persons it affects, 40 percent are over the age of 74 years. 
  3. Aging is generally associated with
    1. increasing risk from toxicity of anti-cancer and other powerful medications
    2. progressive reduction in 
      1. the functional reserve of organs and organ systems
      2. tolerance of physical, emotional, and social stress.
  4. Treatment of persons in the aged population is increasingly important because life expectancy is expected 
    1. to increase, especially in the absence of serious comorbidities
    2. at age 80 years to range from 7 to 9 years.
  5. Healthcare, including oral healthcare, increasingly requires for the stages of aging  assessment methods along the lines of those evolving for cancer treatment, which 
    1. are based on the individual person’s 
      1. performance
      2. autonomy
      3. comorbidities
    2. from the perspective of treatment describe  
      1. the most positive picture, which is of
        1. functional independence
        2. ability to exercise autonomy in 
          1. actions
          2. decision-making
        3. absence of significant comorbidity 
      2. a less positive picture, associated with 
        1. decrease in
          1. functional status
          2. cognitive and mental abilities necessary for autonomy of
            1. action
            2. decision-making
        2. existence of significant comorbidities.

Oral health considerations

  1. The mouth and adjacent tissues 
    1. are the sites of gastrointestinal tumours
    2. are the sources of important signs and symptoms of non-oral  gastrointestinal tumours, which may 
      1. provide the first indications of gastrointestinal tumours
      2. first be detected during oral health inspections in the course of oral healthcare
  2. The risks of gastrointestinal tumours are one of various reasons for careful inspection of the oral cavity and oropharynx during routine care.
  3. Relative to gastrointestinal tumours, benign tumours
    1. are not always harmless because non-malignant tumours may exert pressure on important adjacent organs such as blood vessels, nerves and glands
    2. should, along with all tumours, always be referred for appropriate health-professional advice where this has not been recently obtained. 
  4. When a patient/client reports gastrointestinal tumour, past or present, the medical history taken by the dental hygienist should include questions covering topics such as
    1. conditions such as 
      1. Crohn’s disease (CDHO Advisory)  
      2. ulcerative colitis (CDHO Advisory)
      3. celiac disease (CDHO Advisory)
      4. intestinal polyps
      5. HIV/ AIDS (CDHO Advisory)
      6. immune system disorder
      7. cancer elsewhere in the body
    2. symptoms such as
      1. abdominal pain
      2. weight loss
      3. blood in the stool
      4. watery diarrhea
      5. fatigue, weakness
      6. itching, or yellowish colour to 
        1. conjunctiva
        2. skin
      7. sudden flushing of the head and neck
    3. consumption of high-fat, high-sugar diet
    4. types of medical treatment received or planned.
  5. Gastrointestinal tumours present oral healthcare with particular challenges arising from the precursors and linkages of
    1. tumours in the mouth and adjacent tissues 
      1. on the tongue, which include chronic irritation that arises with oral health conditions, such as
        1. damaged or fractured teeth
        2. ill-fitting denture or dental appliances
        3. overuse of certain oral rinses
        4. chewing tobacco
        5. use of betel quid
      2. that may 
        1. be preceded by oral health conditions such as
          1. erythroplakia and leukoplakia
          2. dental anomalies in the form of impacted or un-erupted teeth with Gardner syndrome
        2. be predisposed to by conditions such as
          1. chronic ulcerative colitis (CDHO Advisory
          2. Crohn’s disease (CDHO Advisory)  
          3. diabetes (CDHO Advisory)
          4. hereditary conditions
        3. be accompanied by comorbidities, complications and associated conditions such as
          1. anemia (CDHO Advisory)  
          2. lymphocytic leukemia (CDHO Advisory
          3. non-Hodgkin lymphoma (CDHO Advisory)
          4. Hodgkin lymphoma (CDHO Advisory)
          5. metastasis
        4. have connections with infections such as
          1. oral human papillomavirus, which 
            1. typically is acquired via oral-genital contact
            2. now is associated with oral tumours
          2. HIV/AIDS (CDHO Advisory)
        5. be associated with risk-related lifestyle factors, such as
          1. smoking
          2. alcohol use and abuse (CDHO Advisory)  
    2. other gastrointestinal tumours that may be
      1. accompanied by treatment-related effects and side-effects in the mouth and adjacent tissues, including
        1. chemotherapy (CDHO Advisory)
        2. radiation therapy (CDHO Advisory)
        3. immunosuppression (CDHO Advisory)
        4. medications
      2. signalled by oral signs and symptoms that are non-specific and which
        1. may relate to
          1. conditions of the mouth
          2. non-oral gastrointestinal tumours 
        2. include
          1. dysphagia
          2. weight loss
          3. anemia
          4. cough
          5. hiccups
          6. gastroesophageal reflux disease (CDHO Advisory), which may be linked with Helicobacter pylori
          7. loss of strength
          8. swelling the cervical and supraclavicular lymph nodes
    3. all or most gastrointestinal tumours, which indicate
      1. need for caution with dietary advice which may be valid
        1. in matters of lifestyle
        2. but not necessarily for combatting risk factors for some gastrointestinal tumours as, for example, with  
          1. dietary fibre
          2. calcium supplementation
      2. significant social considerations relative to prognosis that, with some gastrointestinal tumours can be poor and thus point to the need for
        1. palliation
        2. supportive care
        3. end-of-life care
        4. symptomatic treatment, which 
          1. is as important as controlling disease
          2. should involve attention to oral hygiene
        5. respect for the person’s wishes
        6. appropriate and effective communication with patient/clients, which may be facilitated by family caregivers and companions
      3. value in cooperation by dental hygienists with public-health programs and specialized services, such as
        1. screening programs especially for early detection of curable lesions which are rarely symptomatic
        2. speech and swallowing therapy, which may be required after significant surgery
      4. the importance of awareness on the part of dental hygienists of the influence of preoperative variables in operative safety and post-operative prognosis, such as
        1. poor nutritional status
        2. comorbid conditions which may shorten relapse-free survival in patients with gastrointestinal tumours, such as 
          1. diabetes (CDHO Advisory)
          2. stroke (CDHO Advisory)
          3. chronic obstructive pulmonary disease (CDHO Advisory)
          4. chronic heart failure 
        3. delayed wound healing in previous interventions, which may include oral procedures.


Sourcing medications information

  1. Adverse effect database
  2. Specialized organizations
  3. Medications considerations
    All medications have potential side effects whether taken alone or in combination with other prescription medications, or as over-the-counter (OTC) or herbal medications.
  4. Information on herbals and supplements 
  5. Complementary and alternative medicine

Types of medications

Colon and Rectal cancer

Esophageal cancer

Stomach cancer

Pancreatic cancer

Prevention of polyps

Familial adenomatous polyposis

Side effects of medications

See the links above to the specific medications. 


The dental hygienist in taking the medical  and medications history-taking should 

  1. focus on screening the patient/client prior to treatment decision relative to
    1. key symptoms
    2. medications considerations
    3. contraindications
    4. complications
    5. comorbidities
    6. associated conditions
  2. explore the need for advice from the primary or specialized care provider(s)
  3. inquire about
    1. pointers in the history of significance to gastrointestinal tract tumours
    2. the patient/client’s understanding and acceptance of the need for oral healthcare
    3. medications considerations, including over-the-counter medications, herbals and supplements
    4. problems with previous dental/dental hygiene care
    5. problems with infections generally and specifically associated with dental/dental hygiene care
    6. the patient/client’s current state of health
    7. how the patient/client’s current symptoms relate to
      1. oral health
      2. health generally
      3. recent changes in the patient/client’s condition.


Identifying and contacting the most appropriate healthcare provider(s) from whom to obtain medical or other advice pertinent to a particular patient/client

The dental hygienist should

  1. record the name of the physician/primary care provider most closely associated with the patient/client’s healthcare, and the telephone number
  2. obtain from the patient/client or parent/guardian written, informed consent to contact the identified physician/primary healthcare provider
  3. use a consent/medical consultation form, and be prepared to securely send the form to the provider
  4. include on the form a standardized statement of the Procedures proposed, with a request for advice on proceeding or not at the particular time, and any precautions to be observed.


Infection Control

Dental hygienists are required to keep their practices current with infection control policies and procedures, especially in relation to

  1. the CDHO’s Infection Prevention and Control Guidelines (2022)
  2. relevant occupational health and safety legislative requirements
  3. relevant public health legislative requirements
  4. best practices or other protocols specific to the medical condition of the patient/client.


The dental hygienist 

  1. should not implement the Procedures without prior consultation with the appropriate primary or specialist care provider(s)
    1. if the patient/client’s treatment includes active chemotherapy or radiation therapy
    2. if the patient/client has recently undergone or is about to undergo major surgery for a gastrointestinal tract tumour
    3. if the patient/client’s condition or treatment calls for 
      1. antibiotic prophylaxis
      2. pre-medication 
  2. may postpone the Procedures pending medical advice if the patient/client 
    1. appears debilitated
    2. is experiencing symptoms suggestive of complications of a gastrointestinal tract tumour or its treatment 
    3. has a history of immune system disorder
    4. has not complied with pre-medication, including antibiotic prophylaxis, as directed by the prescribing physician 
    5. has recently changed significant medications, under medical advice or otherwise
    6. recently experienced changes in his/her medical condition such as medication or other side effects of treatment
    7. is unable to provide the dental hygienist with sufficient information about
      1. medications
      2. current or impending surgery for a gastrointestinal tract tumour
      3. drug or alcohol dependency
    8. has symptoms or signs of 
      1. exacerbation of the medical condition
      2. comorbidity, complication or an associated condition of a gastrointestinal tract tumour
    9. not recently or ever sought and received medical advice relative to oral healthcare procedures
    10. is deeply concerned about any aspect of his or her medical condition.


Dental hygienists are required to initiate emergency protocols as required by the College of Dental Hygienists of Ontario’s Standards of Practice, and as appropriate for the condition of the patient/client.

First-aid provisions and responses as required for current certification in first aid.


Subject to Ontario Regulation 9/08 Part III.1, Records, in particular S 12.1 (1) and (2) for a patient/client with a history of gastrointestinal tract tumours, the dental hygienist should specifically record

  1. a summary of the medical and medications history
  2. any advice received from the physician/primary care provider relative to the patient/client’s condition
  3. the decision made by the dental hygienist, with reasons
  4. compliance with the precautions required
  5. all Procedure(s) used
  6. any advice given to the patient/client.


The dental hygienists should 

  1. urge the patient/client to alert any healthcare professional who proposes any intervention or test \
    1. that he or she has a history of gastrointestinal tract tumour
    2. of the medication he or she is taking
  2. should discuss, as appropriate 
    1. the importance of the patient/client’s
      1. self-checking the mouth regularly for new signs or symptoms
      2. reporting to the appropriate healthcare provider any changes in the mouth
    2. the need for regular oral health examinations and preventive oral healthcare 
    3. oral self-care including information about 
      1. choice of toothpaste
      2. tooth-brushing techniques and related devices
      3. dental flossing
      4. oral rinses
      5. management of a dry mouth 
    4. the importance of an appropriate diet in the maintenance of oral health
    5. for persons at an advanced stage of a disease or debilitation
      1. regimens for oral hygiene as a component of supportive care and palliative care
      2. the role of the family caregiver  regimens for oral hygiene, with emphasis on maintaining an infection-free environment through hand-washing and, if appropriate, wearing gloves
      3. scheduling and duration of appointments to minimize stress and fatigue 
    6. comfort level while reclining, and stress and anxiety related to the Procedures
    7. medication side effects such as dry mouth, and recommend treatment
    8. mouth ulcers and other conditions of the mouth relating to gastrointestinal tract tumours, comorbidities, complications or associated conditions, medications or diet
    9. pain management.



  1. Promoting health through oral hygiene for persons who have gastrointestinal tract tumours.
  2. Reducing adverse effects, through the early detection and appropriate referral of a gastrointestinal tumour in the mouth and adjacent tissues. 
  3. Reducing the risk that oral health needs are unmet. 


  1. Causing infection in persons/clients who are undergoing chemotherapy, radiation therapy or who are subject to immunosuppression by medications.
  2. Performing the Procedures at an inappropriate time, such as 
    1. in the presence of comorbidities, complications or associated conditions for which prior medical advice is required
    2. in the presence of acute oral infection without prior medical advice.
  3. Disturbing the normal dietary and medications routine of a person with gastrointestinal tract tumours.
  4. Inappropriate management of pain or medication.






2017-07-26 (colorectal cancer and related content only); 2020-01-20


College of Dental Hygienists of Ontario, regulatory body
Greyhead Associates, medical information service specialists


College of Dental Hygienists of Ontario


College of Dental Hygienists of Ontario, Practice Advisors


Dr Gordon Atherley
O StJ , MB ChB, DIH, MD, MFCM (Royal College of Physicians, UK), FFOM (Royal College of Physicians, UK), FACOM (American College of Occupational Medicine), LLD (hc), FRSA

Dr Kevin Glasgow

Lisa Taylor

Giulia Galloro

Kyle Fraser
RDH, BComm, BEd, MEd


The College of Dental Hygienists of Ontario gratefully acknowledges the Template of Guideline Attributes, on which this advisory is modelled, of The National Guideline Clearinghouse™ (NGC), sponsored by the Agency for Healthcare Research and Quality (AHRQ), U.S. Department of Health and Human Services.

Denise Lalande
Final layout and proofreading

© 2011, 2017, 2020 College of Dental Hygienists of Ontario


1 Persons includes young persons and children.
2 CCO’s ColonCancerCheck program no longer recommends screening with the guaiac fecal occult blood test (gFOBT) as of 2019.