You are using an outdated browser. We suggest you update your browser for a better experience. Click here for update.
Close this notification.
Skip to main content Skip to search

Colorectal Cancer Screening Recommendations Summary

Evidence-based recommendations from ColonCancerCheck, Ontario’s colorectal cancer screening program. Also available as a handout: ColonCancerCheck (CCC) Screening Recommendations Summary.

Screening People at Average Risk of Colorectal Cancer

  • Asymptomatic people ages 50 to 74 without a family history of colorectal cancer should be screened with a fecal occult blood test (FOBT) every 2 years.
  • Abnormal FOBT 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.
  • Due to insufficient evidence, the following tests are not recommended for colorectal cancer screening:
    • Metabolomics (blood or urine) tests
    • DNA (blood or stool) tests
    • Computed tomography colonography
    • Capsule colonoscopy
    • Double contrast barium enema

 

Average risk means:

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

 

Note: We are planning to implement fecal immunochemical testing (FIT) in the ColonCancerCheck program as the recommended screening test for those at average risk of developing colorectal cancer.

Screening People at Increased Risk of Colorectal Cancer

  • Asymptomatic people should be screened with colonoscopy if they have a family history of colorectal cancer that includes 1 or more first-degree relatives (parent, sibling or child) with the disease. People who have a first-degree relative with colorectal cancer should begin screening with colonoscopy at age 50, or 10 years earlier than the age their relative was diagnosed, whichever occurs first.
  • Colonoscopy should be repeated:
    • 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.

Increased risk means people with a family history of colorectal cancer that includes 1 or more first-degree relatives (parent, sibling or child) who have been diagnosed with colorectal cancer, but do not meet the criteria for colorectal cancer hereditary syndromes.

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

Over Age 74

The ColonCancerCheck program does not recommend routine screening for people over 74.

 

Generally, the expected benefits of screening for people over 74 are lower, while the associated risks are greater. This also applies to people under 75 who suffer from severe comorbidities. Experts agree that a person whose life expectancy is less than 5 years should not be screened. However, there may be instances where a healthy older adult wishes to be screened beyond the recommended age range.

 

The benefits of screening for cancer in older adults vary, depending on someone’s life expectancy and screening history. The potential for harm (including complications from diagnostic procedures and psychological distress from screening) may increase. Therefore, the decision to screen depends on multiple factors.

 

Inflammatory Bowel Disease

A person with a history of ulcerative colitis or Crohn’s disease 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 are at high risk for colorectal cancer. These include:

  • 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

Patients who are unable to determine 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 occult blood test (FOBT) or colonoscopy.

 

Only about 11% of the Ontario population meets the ColonCancerCheck definition of increased risk for colorectal cancer based on 1 or more first-degree relatives (parent, sibling or child) with the disease

 

Presenting with Signs and Symptoms

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

  • A drop in red cell count (anemia) caused by a lack of iron
  • Blood (either bright red or very dark) in the stool (poop)
  • Unexplained weight loss
  • New and persistent diarrhea, constipation or feeling that the bowel does not empty completely
  • Stools that are narrower than usual
  • New and persistent stomach discomfort

 

There is no role for FOBT in people with symptoms, since the decision to investigate them should be based on their clinical presentation and not influenced by the result of the FOBT. Also, a negative FOBT may lead to diagnostic delay in these patients.

Use of Other Tests for Screening People at Average Risk

Metabolomic Tests

Based on a systematic review of the evidence, ColonCancerCheck recommends against screening for colorectal cancer using 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.

 

We evaluated the existing evidence for screening adults at average risk of colorectal cancer in the context of an organized, population-based screening program. The objectives were to identify the benefits and harms of screening people at average risk and to recommend screening tests based on the strength of the evidence.

 

This thorough review of the clinical evidence revealed insufficient evidence to support the use of metabolomic tests to screen people at average risk of colorectal cancer.

 

Colonoscopy

ColonCancerCheck considered the current clinical evidence on average-risk colonoscopy screening, as well as multiple context-specific criteria (e.g., feasibility and cost-effectiveness) when developing the organized, population-based screening program recommendations.

 

At this time, there is insufficient high-quality, direct evidence to support screening people at average risk of colorectal cancer with colonoscopy.  

 

Evidence from flexible sigmoidoscopy research can inform the assessment of colonoscopy in the average-risk population. It is anticipated that the benefits of screening with colonoscopy would be at least equivalent to those observed for screening with flexible sigmoidoscopy; the magnitude of additional benefits and harms, if any, is unknown. Therefore, due to a lack information on the ratio of benefits to harms, colonoscopy is not included in the ColonCancerCheck screening recommendations.

 

About the Recommendations

In November 2015, we 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:

  • benefits and harms of screening 
  • optimal primary colorectal cancer screening tests
  • appropriate ages to start and end screening
  • intervals for screening recall

 

The evidence summary reported what is known about the clinical effectiveness and safety of colorectal cancer screening tests. This was the first step in developing these 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 for that purpose. (Learn more about the Program in Evidence-Based Care.)

 

The next phase 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 physicians
  • 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 by the Canadian Task Force on Preventive Health Care in February 2016. Both organizations recommend screening people at average risk of colorectal cancer with fecal occult blood testing or flexible sigmoidoscopy.

 

The task force recommends against colonoscopy to screen people at average risk. ColonCancerCheck found insufficient high-quality, direct evidence to support screening people at average risk of colorectal cancer with colonoscopy, and therefore ColonCancerCheck did not include colonoscopy in its recommendations.

 

Evidence from flexible sigmoidoscopy research can be used to inform the assessment of colonoscopy in this population. It is anticipated that the benefits of screening with colonoscopy would be at least equivalent to those observed for screening with flexible sigmoidoscopy; the magnitude of additional benefits and harms, if any, is unknown.

 

Therefore, due to a lack information on the balance of benefits and harms, colonoscopy is not included in the ColonCancerCheck screening recommendations.

 

Flexible Sigmoidoscopy – Screening Interval Extended to 10 Years

The ColonCancerCheck screening recommendations released in 2016 are based on a systematic review of the clinical evidence, additional information (e.g., cost-effectiveness), existing program design, public acceptability and feasibility, and advice from a multidisciplinary expert panel. The 10-year interval for flexible sigmoidoscopy screening was based on several key considerations.

 

Three randomized controlled trials were identified that evaluated colorectal cancer screening using once-in-a-lifetime flexible sigmoidoscopy. The observation window was at least 10 years for all 3 trials; the reported benefits (reduced mortality and incidence) were measured at this time (see table 1).

 

Table 1. Flexible Sigmoidoscopy Randomized Control Trial Data
Study Name: Author, Year  Country  Sample Size FS  Sample Size Control  Median Length of Follow-Up (Years)  Relative Risk (95% CI) 
CRC Incidence
Relative Risk (95% CI) 
CRC Mortality
SCORE:
Segnan, 2011
Italy 17,136 17,136 Incidence:
10.5
Mortality:
11.4
0.82 (0.69-0.97) 0.78 (0.56-1.08)
UKFSST:
Atkin, 2010
UK 57,099 112,939 11.2 0.77 (0.70-0.84) 0.69 (0.59-0.80)
NORCCAP:
Holme, 2014
Norway 20,572 78,220 11 0.87 (0.76-1.00) 0.80 (0.62-1.04)

Abbreviations: CI: confidence interval; CRC: colorectal cancer; NORCCAP: Norwegian Colorectal Cancer Prevention; SCORE: Screening for Colon Rectum; UKFSST: UK Flexible Sigmoidoscopy Screening Trial

The colorectal cancer adenoma–carcinoma progression sequence is believed to take more than 10 years, especially for cancers on the left side of the colon. Therefore, re-screening with flexible sigmoidoscopy after 5 years is expected to have limited utility for left-sided cancer and adenoma detection.

 

This recommendation aligns with the 2016 colorectal cancer screening guidelines from the Canadian Task Force on Preventive Health Care and the draft colorectal cancer screening recommendations from the U.S. Preventive Services Taskforce released for public comment in the fall of 2015.

 

Contact

For more information and resources, contact: