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Colorectal Cancer Screening Recommendations Summary

Evidence-based recommendations from ColonCancerCheck, Ontario’s colorectal cancer screening program. Also available as a handout: ColonCancerCheck (CCC) Guide to Average Risk Screening with the Fecal Immunochemical Test (FIT) in Ontario.

 

Screening People at Average Risk of Colorectal Cancer

  • Asymptomatic people should be screened with a fecal immunochemical test (FIT) every 2 years.
  • Abnormal FIT results should be followed up with colonoscopy within 8 weeks. People ages 50 to 74 without a family history of colorectal cancer who choose to be screened with flexible sigmoidoscopy should be screened every 10 years.

Average risk means:

  • people ages 50 to 74 with no first-degree relative (parent, brother, sister or child) who has been diagnosed with colorectal cancer
  • people with no personal history of pre-cancerous colorectal polyps requiring surveillance or inflammatory bowel disease (i.e., Crohn’s disease involving the colon, or ulcerative colitis)

Screening with FIT

Ordering a FIT for a Patient

  • Complete a FIT requisition to order a fecal immunochemical test (FIT) kit for eligible, average risk people. FIT cannot be ordered using the Ministry of Health and Long-Term Care Laboratory Requisition or a hospital laboratory requisition. Instructions for completing the FIT requisition are also available.
  • LifeLabs will mail a FIT kit to a screening participant’s Ontario mailing address of choice. Participants may choose to have their FIT kit sent to their main mailing address (e.g., their home) or an alternate Ontario mailing address (e.g., a health centre or a relative’s home) if they are not sure how long they will be at their main address (e.g., they are home insecure or possibly choosing to move). This alternate address can be provided on the requisition in the FIT Kit Mailing Address section. The FIT Kit Mailing Address will not be used for program correspondence.
  • LifeLabs will mail a FIT package to patients’ Ontario mailing address of choice. The requisition can be used to indicate that the FIT kit should be mailed to an alternate address (specified on the requisition as the ‘FIT Kit Mailing Address’), which may differ from the patient’s primary mailing address. The FIT Kit Mailing Address will not be used for program correspondence.
  • Ensure the accuracy of a participant’s mailing address information (including an alternate mailing address for the FIT kit, if applicable) and confirm their date of birth.
  • Submit completed FIT requisitions directly to LifeLabs (fax: 1-833-676-1427). Do not give your patient the FIT requisition.
  • LifeLabs will assess the requisition for completeness and verify patient eligibility, based on OHIP, age and FIT screening status.
  • LifeLabs will then send a FIT kit to your patient. You will not be able to stock FIT kits in your offices.  
  • ColonCancerCheck (CCC) Guide to Average Risk Screening with the Fecal Immunochemical Test (FIT) in Ontario provides a quick-reference guide on how to order a FIT kit for a screening participant.
  • Direct questions to LifeLabs at 1-833-676-1426.
  • Providers in hospital settings: With the transition to FIT, primary care providers and specialists who practice in hospital settings can use the new ColonCancerCheck FIT requisition to order FIT for the purpose of colorectal cancer screening. Cancer Care Ontario does not recommend using FIT for reasons other than colorectal cancer screening (e.g., FIT is not recommended for diagnostic use or point-of-care testing). Fecal-based testing has a low sensitivity for the diagnosis of colorectal cancer in people with symptoms, and using fecal-based testing as a diagnostic tool (e.g., use in the emergency room for people with symptoms suggestive of gastrointestinal bleeding) has been shown to lead to diagnostic delays and inefficiencies.

Clinical Considerations

People with rectal bleeding

  • Regardless of a person’s age or whether they are due for screening, people with uninvestigated symptoms need a diagnostic work-up. Do not screen symptomatic people with FIT.
  • As part of a thorough physical examination, it is important to do a digital rectal examination on people with rectal bleeding that has not been investigated. It is not appropriate to perform an office-based guaiac fecal occult blood test.
  • Endoscopic evaluation with flexible sigmoidoscopy or colonoscopy is necessary to investigate the cause of the bleeding, even if the digital rectal examination reveals a benign source of bleeding (e.g., fissure).

People with iron deficiency anemia

  • Iron deficiency anemia may be a presentation of colorectal cancer. People who present with unexplained iron deficiency anemia should be referred to have a colonoscopy on a prompt basis.
  • Stool-based testing (with FIT) should not be used to guide the decision to refer or investigate people with symptoms or other conditions suggestive of colorectal cancer because it may lead to a delay in diagnosis.

People bleeding intermittently from a previously investigated benign source (e.g., investigated hemorrhoids), menstruation or dental work

  • People who have undergone dental work that resulted in bleeding should wait 3 days before completing a FIT. People who are bleeding from a previously investigated benign source or from menstruation can get screened with FIT if they complete the FIT 3 days after the bleeding has stopped. For people who cannot screen with FIT because their bleeding is more frequent than every 3 days, flexible sigmoidoscopy is an acceptable screening test.
  • People who have a previously investigated benign source of bleeding, but experience a change in symptoms should be thoroughly investigated and should not complete the FIT.
  • People with bleeding from a non-confirmed source should be investigated. Do not use FIT or any fecal occult blood test for these people. Cancer Care Ontario does not recommend using FIT for reasons other than colorectal cancer screening (e.g., for diagnostic use, point-of-care testing). Fecal-based testing has a low sensitivity for the diagnosis of colorectal cancer in people with symptoms, and using fecal-based testing as a diagnostic tool (e.g., use in the ER for people presenting with symptoms suggestive of GI bleeding) has been shown to lead to diagnostic delays and inefficiencies.

People with hemoglobinopathies

  • Based on available evidence, people with common hemoglobin variants can be screened with FIT.
  • FIT detects blood in the stool using polyclonal antibodies that recognize different sites on the human globin molecule.
  • A hemoglobinopathy is a condition characterized by abnormal synthesis of 1 or more of hemoglobin’s 4 chains, resulting in the production of hemoglobin (Hb) variants. Based on the limited literature examining this question, FIT seems to adequately detect blood in the majority of tested cases with hemoglobin variants (e.g., HbC, HbD, HbE, sickle cell trait, sickle cell disease, sickle C and beta-thalassemia carrier). The available literature suggests that FIT has a reduced ability to detect beta-thalassemia major, as well as HbF. However, due to frequent blood transfusions in adults with these conditions, the proportion of abnormal hemoglobin variants is unlikely to be significant.
  • There is, therefore, not enough evidence to suggest that people with common hemoglobin variants should refrain from screening with FIT. ColonCancerCheck recommends screening with FIT for eligible patients with these conditions. The ColonCancerCheck program will continue to monitor the evidence in this area and will revise program recommendations as appropriate.

People taking iron

  • People taking iron can do a FIT without any changes to their diet or supplementation. There are no dietary or supplement restrictions because FIT detects blood in the stool using antibodies specific for human globin. FIT does not detect iron. Therefore, dietary iron or dietary sources of non-human hemoglobin will not cause false-positives.

People taking non-steroidal anti-inflammatory drugs or oral anti-coagulants

  • People taking non-steroidal anti-inflammatory drugs or oral anti-coagulants can do the FIT without any changes to their use of these medications. This decision is supported by several recent systematic reviews and meta-analyses.

Screening Interval

  • FIT should be performed every 2 years in people ages 50 to 74 who are average risk for colorectal cancer.
  • If someone’s FIT result is abnormal, a colonoscopy should be performed within 8 weeks.
  • If the colonoscopy finds no polyps or only hyperplastic polyps in the recto-sigmoid colon, screening with FIT should resume after 10 years.
  • If the colonoscopy finds polyps, please refer to ColonCancerCheck’s Recommendations for Post-Polypectomy Surveillance.
  • If someone is at increased risk for colorectal cancer, see “Screening People at Increased Risk of Colorectal Cancer” below for more information.  
 

Abnormal Results

  • Abnormal FIT results should be followed up with colonoscopy within 8 weeks.
  • The 8-week benchmark was set by the Canadian Association of Gastroenterology Wait Time Consensus Group and aligns with recommendations set by the Canadian Partnership Against Cancer’s National Colorectal Cancer Screening Network.
  • Colonoscopy is promptly required after someone has an abnormal FIT result because there is a higher likelihood that they have colorectal cancer than someone at average risk who is being screened with colonoscopy, or someone with certain gastrointestinal symptoms who is having a colonoscopy. Diagnostic delays following an abnormal FIT result could allow the cancer to progress to a more advanced stage and may lead to delays in receiving treatment.
  • People with an abnormal FIT result are likely to feel anxious and concerned as they wait for their follow-up. To help manage anxiety, primary care providers should promptly refer their patients for colonoscopy so that the procedure can be completed within 8 weeks of the abnormal FIT result.
  • Repeating a FIT after an abnormal FIT or gFOBT is not appropriate and can lead to delays in diagnosis and treatment. LifeLabs will not accept requests to repeat FIT after an abnormal result.
  • Follow-up colonoscopies after abnormal FIT results are expected to require more time, expertise and equipment, given the higher likelihood of advanced neoplasia (including colorectal cancer and high risk adenomas) in people with an abnormal result. These potentially more complex colonoscopies are the reason not all facilities will offer FIT-positive colonoscopies and usual routes for referral may not apply.
  • Be aware of any regional strategies to ensure timely access to colonoscopy for your patients with abnormal FIT results. For a list of facilities funded by Cancer Care Ontario to provide colonoscopies for patients with an abnormal FIT result, please visit cancercareontario.ca/FITcolonoscopy.

Screening People at Increased Risk of Colorectal Cancer

  • Someone is considered to be at increased risk for colorectal cancer if they have a family history of the disease that includes 1 or more first-degree relatives (parent, brother, sister or child) who have been diagnosed with this disease.
  • ColonCancerCheck recommends that people with no symptoms who are at increased risk of getting colorectal cancer get screened with a colonoscopy. Someone at increased risk should start screening at age 50, or 10 years earlier than the age their relative was diagnosed with colorectal cancer, whichever comes first.
  • The amount of time someone should wait until getting screened again after a normal colonoscopy result should be based on their family history:  
  • Every 5 years for people with a first-degree relative who was diagnosed with colorectal cancer before age 60
  • Every 10 years for people with a first-degree relative who was diagnosed with colorectal cancer at age 60 or older
  • The ColonCancerCheck program does not screen people at high risk for colorectal cancer who have hereditary colorectal cancer syndromes, such as such as familial adenomatous polyposis (FAP) and Lynch syndrome.

For information on genetic testing and hereditary symptoms, please see the Ministry of Health and Long-Term Care’s OHIP Bulletin 4381 or visit the Canadian Cancer Society.

Screening People Outside the Screen-Eligible Population

People Under Age 50

  • The ColonCancerCheck program does not recommend regular screening for people younger than age 50 with no first-degree relatives who have been diagnosed with colorectal cancer.
  • Even though the number of colorectal cancers being diagnosed in younger adults is increasing in Canada, it is still very low in adults younger than age 50.
  • An estimated 93% of new colorectal cancer cases will be diagnosed in people older than age 50 in 2018.
  • Because the risk of cancer is much higher in people older than age 50, this is still the group that will benefit most from screening.
  • However, people of any age with symptoms (e.g., rectal bleeding) or conditions (e.g., iron deficiency anemia) related to colorectal cancer, need to be assessed and promptly referred to a specialist, if appropriate. Do not use FIT in people who have possible colorectal cancer symptoms because this practice may lead to a delay in diagnosis.

People Over Age 74

  • The ColonCancerCheck program does not recommend regular screening for people older than age 74. However, someone may choose to get screened after age 74 if the benefits of screening outweigh the risks. 
  • People expected to live less than 5 years should not get screened.
  • Generally, people older than age 74 do not benefit as much from screening and are at more risk of having complications when they get screened for colorectal cancer. People younger than 75 with severe medical conditions may also experience more risks than benefits from screening.
  • Some people ages 75 to 85 may benefit from screening, especially those who have never been screened for colorectal cancer and, to a lesser extent, those who are very healthy.
  • Considerations for deciding when to screen people ages 75 to 85 for colorectal cancer include how long someone is expected to live, their screening history, and whether they are willing and able to have a follow-up colonoscopy.
  • The ColonCancerCheck program strongly recommends against colorectal cancer screening in people older than age 85. LifeLabs will reject FIT requisitions submitted for people older than age 85.

Inflammatory Bowel Disease

Someone with a history of ulcerative colitis or Crohn’s disease involving the colon should be under the ongoing care of a specialist. Decisions such as colorectal cancer risk and dysplasia surveillance will be made by that specialist.

High Familial Risk

People with certain hereditary colorectal cancer syndromes, including these ones, are at high risk for colorectal cancer:

  • Familial adenomatous polyposis (FAP) and Lynch syndrome
  • MYH-associated polyposis
  • Peutz-Jeghers syndrome
  • Juvenile polyposis

Visit the Canadian Cancer Society for more information.

ColonCancerCheck does not have an organized screening program for people at high risk for colorectal cancer due to hereditary colorectal cancer syndromes. However, people considered to be at high risk can be referred to a familial cancer genetics clinic or genetics clinic whether or not they have cancer. For more information, please see the Ministry of Health and Long-Term Care’s OHIP Bulletin 4381.

Unknown Family History

  • People who do not know their family history (e.g., people who have no access to the medical history of their biological parents) should start screening at age 50 with the fecal immunochemical test (FIT).
  • Only about 11% of the Ontario population meets ColonCancerCheck’s definition of increased risk for colorectal cancer based on having 1 or more first-degree relatives (parent, brother, sister or child) with the disease.

 

People with Symptoms or Conditions

People presenting with new onset of the following symptoms or conditions should be referred to a specialist for evaluation and consideration of endoscopy:

  • Unexplained iron deficiency anemia
  • Blood (either bright red or very dark) in the stool
  • Unexplained weight loss
  • New and persistent diarrhea, constipation or feeling that the bowel does not empty completely
  • New and persistent abdominal discomfort

FIT should not be used in people with symptoms (e.g., rectal bleeding) or conditions (e.g., iron deficiency anemia) related to colorectal cancer. These people have a higher likelihood of an underlying colorectal cancer and should be directly referred to colonoscopy. The decision to investigate symptoms or conditions related to colorectal cancer should be based on clinical presentation and not influenced by the result of a FIT. Also, a normal FIT may lead to diagnostic delay in people with symptoms.  

Use of Other Tests for Screening People at Average Risk

Guaiac Fecal Occult Blood Test (gFOBT)

ColonCancerCheck no longer recommends that people at average risk of colorectal cancer screen with the guaiac fecal occult blood test (gFOBT). Although there is high-quality scientific evidence to support screening with gFOBT, FIT offers several advantages over gFOBT. People prefer FIT because it is easier to do. FIT is also better at detecting colorectal cancer and some pre-cancerous polyps in comparison with gFOBT.  

Metabolomic Tests

  • Metabolomic tests look for metabolites (i.e., the intermediates and products of metabolism) in blood or urine and claim to assess someone’s risk of colorectal cancer. Currently, only blood tests for metabolites are available in Ontario.
  • Based on a systematic review of the evidence, ColonCancerCheck recommends against screening for colorectal cancer using metabolomic tests.

For more information on the evidence, see Colorectal Cancer Screening in Average Risk Populations: Evidence Summary.

Colonoscopy

The ColonCancerCheck program does not recommend screening people at average risk with colonoscopy.

  • There is limited evidence comparing FIT with colonoscopy screening for colorectal cancer incidence and mortality in people at average risk. Several large, randomized controlled trials are under way to address this question, with preliminary results suggesting that FIT offers comparable benefits.
  • Results from a large, ongoing randomized controlled trial in Spain suggest that FIT was as good as colonoscopy at detecting colorectal cancer (33 cancers vs. 30 cancers; P value = not significant) on an intention to screen basis (i.e., analyses are based on all participants initially randomized to that arm, regardless of whether or not they complete screening or whether they withdraw from the study—this approach better reflects the real-life impact of screening as it captures participants’ acceptance of the test as well as its accuracy). While the study found that colonoscopy was significantly better at detecting advanced adenomas than the 1 time use of FIT (514 vs. 231; P value = <0.001), this benefit may not be sustained over time because people in the FIT arm will be recalled for screening 4 more times over the course of the study; by comparison, those in the colonoscopy arm are not re-invited for screening throughout this 10-year interval. The study also found that 23% of people invited for colonoscopy opted to switch to FIT, compared with only 1% of people invited for FIT who switched to colonoscopy (crossover rate odds ratio: 16.8; 95% confidence interval, 13.9 to 20.2; p<0.001)), providing further evidence that people prefer screening with FIT over colonoscopy.
  • Unlike colonoscopy, FIT is a non-invasive screening test. While colonoscopy is generally a safe exam, complications can occur, including those related to bowel preparation (e.g., falls and injuries such as a hip fracture, and electrolytic abnormalities) and sedation. Possible colonoscopy-related complications include (but are not limited to): perforation, post-polypectomy bleeding, cardiac events, syncope, hypotension and death (in rare cases).
  • In the Spanish randomized controlled trial, the risk of complications was statistically significantly lower in the FIT arm than in the colonoscopy arm (0.1% vs. 0.5%; P value = < 0.001). 
  • Colonoscopy remains the appropriate test for follow-up of abnormal FIT results. Colonoscopy also remains the recommended test for screening people at increased risk of colorectal cancer in the ColonCancerCheck program.

About the Recommendations

Evidence Summary

In November 2015, ColonCancerCheck published a systematic review that evaluated the existing evidence for screening adults at average risk for colorectal cancer in the context of an organized, population-based screening program.

The main objectives of Colorectal Cancer Screening in Average Risk Populations: Evidence Summary were to identify the following:

  • Benefits and harms of screening 
  • Optimal primary colorectal cancer screening tests
  • Appropriate ages to start and end screening
  • Screening intervals

The evidence summary reported what is known about the clinical effectiveness and safety of colorectal cancer screening tests. This evidence summary was the first step in developing revised average risk screening recommendations for ColonCancerCheck.

The evidence summary was developed by our internationally recognized Program in Evidence-Based Care, with the assistance of a guideline working group formed specifically to help with the development of the evidence summary. (Learn more about the Program in Evidence-Based Care)

The next phase of developing the recommendations was to consider additional information, such as cost-effectiveness, existing program design, public acceptability and feasibility from an organizational and economic perspective. A large, multidisciplinary expert panel met to discuss the evidence and provide implementation considerations. Panel members included:

  • representatives from national and international screening programs
  • primary care providers
  • general surgeons
  • gastroenterologists
  • pathologists and laboratory medicine professionals
  • nurse endoscopists
  • members of the public

The final phase brought the clinical evidence and implementation considerations provided by the expert panel together as key inputs in the development of the updated screening recommendations.

Alignment with the Canadian Task Force on Preventive Health Care

  • The ColonCancerCheck screening recommendations align closely with the recommendations released in February 2016 by the Canadian Task Force on Preventive Health Care. Both organizations recommend screening people at average risk of colorectal cancer with either fecal occult blood testing (including the guaiac fecal occult blood test [gFOBT] or the fecal immunochemical test [FIT]) every 2 years, or flexible sigmoidoscopy. Neither organization recommends screening people at average risk with colonoscopy.

Fecal Immunochemical Test (FIT) Replaces the Guaiac Fecal Occult Blood Test (gFOBT)

ColonCancerCheck has now transitioned from the guaiac fecal occult blood test (gFOBT) to the fecal immunochemical test (FIT) as its recommended screening test for people at average risk.

Advantages of FIT 

  • FIT is a more sensitive screening test than gFOBT, which means that it is better at detecting colorectal cancer and some pre-cancerous polyps.
  • FIT is specific for human hemoglobin, which means it will not mistake dietary sources of blood or other substances for human blood. 
  • There are no dietary (e.g., vitamin C) or medication (e.g., anticoagulants) restrictions when taking this test.
  • The FIT collection device is designed to be easy to use and reduces the amount of contact people have with their stool when collecting it.  
  • Only 1 sample is needed.
  • FIT testing will be automated at LifeLabs, which makes the interpretation of test results more consistent.  
  • Research has shown that people prefer screening with FIT over gFOBT, leading to increases in colorectal cancer screening participation.   

Flexible Sigmoidoscopy

  • The effectiveness of screening with flexible sigmoidoscopy is demonstrated in 4 high-quality randomized controlled trials. These trials began in the 1990s and were published from 2010 to 2014. The intervention was either a 1 time flexible sigmoidoscopy or an initial flexible sigmoidoscopy followed by a second by flexible sigmoidoscopy at 3 to 5 years. Median follow-up ranged from 10.5 to 12 years. Across the 4 trials, colorectal cancer incidence was reduced by 18% to 23% and colorectal cancer mortality was reduced by 22% to 31%.
  • The ColonCancerCheck program considers flexible sigmoidoscopy an acceptable screening option for people at average risk of colorectal cancer. People who choose to be screened with flexible sigmoidoscopy should be screened every 10 years.

Contact

For more information and resources, contact Cancer Care Ontario: