Guideline recommends routine screening for asymptomatic adults between 50-74 years of age for colorectal cancer
OTTAWA, ON, February 22, 2016 – The Canadian Task Force on Preventive Health Care (CTFPHC) has released its recommendations for Canadian clinicians and policymakers on screening tests, screening intervals and recommended ages to start and stop screening for colorectal cancer (CRC) in adults aged between 50 and 74 years old who are not at high risk for CRC. These recommendations were published today in the Canadian Medical Association Journal (CMAJ).
“As the second most common cause of cancer death in men and the third most common cause in women, routine screening for colorectal cancer in adults aged 50-74 can lead to early detection, improved treatments and fewer deaths,” said Dr. Maria Bacchus, chair of the CTFPHC guideline working group. “Studies show that with increasing age, cases and deaths due to CRC increase, particularly among the 60-74 age group and therefore we strongly recommend screening among this age group,” added Bacchus.
The guideline, developed by the CTFPHC, an independent body of primary care and prevention experts, examined the best and most current scientific evidence related to screening tests to formulate the following key screening recommendations.
- For adults between 60 and 74 years of age, the CTFPHC strongly recommends screening for colorectal cancer every two years using Fecal Occult Blood Test (FOBT) (either FOBT with a guaiac smear method (gFOBT) or Fecal Immunochemical Test (FIT) or every ten years using flexible sigmoidoscopy.
- For adults aged 50 to 59, the CTFPHC provided a weak recommendation for screening every two years using Fecal Occult Blood Test (FOBT) (either FOBT with a guaiac smear method (gFOBT) or Fecal Immunochemical Test (FIT) or every ten years using flexible sigmoidoscopy.
- For adults 75 years and older, the CTFPHC provided a weak recommendation against screening for colorectal cancer due to lack of evidence.
- The CTFPHC does not recommend using colonoscopy as a primary screening test for colorectal cancer due to lack of evidence.
This new guideline, available at: www.canadiantaskforce.ca updates prior guidelines developed by CTFPHC in 2001 based on new technology and practices. A clinician recommendation table and a patient FAQ are also available on the CTFPHC website.
Since 2001, CTFPHC has recommended screening with either FOBT or flexible sigmoidoscopy. Provincial screening programs recommend screening with FOBT (the majority recommend FIT) every 1-2 years, which is consistent with the current CTFPHC recommendation. The United States Preventive Services Task Force (USPSTF) published recommendations in 2008, and recommended FOBT, flexible sigmoidoscopy, or colonoscopy. An update of the USPSTF colorectal cancer screening guideline is currently under development.
CTFPHC Findings:
Screening
- Based on available evidence, the CTFPHC determined that gFOBT, FIT and flexible sigmoidoscopy are reasonable screening tests for patients aged 50-74 years who are not at high risk1 for CRC.
- However, in the judgment of the CTFPHC, the lower absolute benefit expected from screening people aged 50-59 years warrants a weak recommendation as compared to the strong recommendation for people aged 60-74 years.
- Randomized controlled trial data show that screening with gFOBT or flexible sigmoidoscopy reduces incidence of late-stage colorectal cancer and colorectal cancer deaths.
Harms
FOBT
- The primary harms for FOBT are false positives and false negatives2. As false positive can potentially lead to more harm from subsequent unnecessary testing.
Flexible Sigmoidoscopy
- The harms of the flexible sigmoidoscopy screening tool are rare and occur in less than 1% of patients. Those potential harms include intestinal perforation, minor bleeding, major bleeding and death.
- There is only very low quality evidence available to assess the harms of diagnostic colonoscopy (as a follow-up test for either positive FOBT or flexible sigmoidoscopy screening) which included intestinal perforation (0.061 % of patients), minor bleeding (0.27% of patients), major bleeding (0.11% of patients), and death (0.035% of patients).
“There are many ongoing studies surrounding CRC screening including the use of alternate screening tests to aid in the detection and treatment of this disease,” said Dr. Maria Bacchus, chair of the CTFPHC guideline working group. “However, patients should discuss screening for colorectal cancer with their family physician who will consider the patient’s preferences and values as well as access to resources to determine the right screening test and interval for them.”
For the complete report and details on the CTFPHC’s findings and recommendations and accompanying patient and clinician Knowledge Transfer tools, please visit: www.canadiantaskforce.ca
About the Canadian Task Force on Preventive Health Care
The Canadian Task Force on Preventive Health Care (CTFPHC) has been established to develop clinical practice guidelines that support primary care providers in delivering preventive health care. The mandate of CTFPHC is to develop and disseminate clinical practice guidelines for primary and preventive care, based on systematic analysis of scientific evidence.
1High risk is defined as: those with previous CRC or polyps, inflammatory bowel disease, signs or symptoms of CRC, history of CRC in one or more first degree relatives, or adults with hereditary syndromes predisposing to colorectal cancer.
2A false positive means that a test says someone has colorectal cancer when they actually do not while a false negative is when a test says someone does not have CRC and when in fact they do. While this is the usual meaning in the screening context the test is not diagnostic so a false positive does not mean you have cancer.