Study Material

Clinical Context

Colorectal cancer is one of the most common cancers diagnosed in women and men, and the authors of the current recommendations noted that the lifetime risk for colorectal cancer is approximately 5% among adults living in Western countries. Most adults in the prime ages for screening have a risk for colorectal cancer between 1% and 7%. Age is certainly a major risk factor for colorectal cancer; the risk for colorectal cancer increases by 0.5% to 1.5% at 5-year intervals after age 50 years.

The 5-year survival of colorectal cancer is 65%. Screening for colorectal cancer improves rates of cancer survival, yet many adults forgo testing. Adherence to fecal testing programs in Australia, Europe, America, and Asia ranges between 16% and 68%, and participation rates for colonoscopy in a randomized trial based in Europe ranged from 23% to 61%.

Participation in colorectal cancer screening is far from 100%, and new approaches are welcome. The current guidelines offer an alternative approach in suggesting that colorectal cancer screening should be based on baseline risk.

Study Synopsis and Perspective

For the first time, a guideline recommends that screening for colorectal cancer should not be routinely recommended for all adults ages 50 to 79 years but instead should be limited to individuals with an elevated level of risk.

The new guideline, from an international panel of experts, goes against the grain. At present, many countries recommend routine screening for all older individuals, and recently some groups have even lowered the starting age to 45 years.

The new guidelines were published online October 2 in BMJ.

Screening should be recommended for adults with a cumulative cancer risk of 3% or more in the next 15 years, the point at which the balance between benefits and harms favors screening, said the authors, led by Lise Helsingen, MD, Clinical Effectiveness Research Group, University of Oslo in Norway.

Screening is not recommended when cumulative risk is below 3%.

Risk calculation (over 15 years) can be made using the free online QCancer® calculator, advised the panel.

"The optimal choice for each person requires shared decision making," Helsingen commented.

A risk-based approach is "increasingly regarded as the most appropriate way to discuss cancer screening" and is already used with patients in prostate and lung cancer screening, wrote Philippe Autier, PhD, International Prevention Research Institute, Lyon, France, in an accompanying editorial.

The National Comprehensive Cancer Network® (NCCN®) said the new guide does not change their screening recommendation.

"At this time, NCCN continues to endorse screening for colorectal cancer in average risk individuals age 50-75," said Dawn Provenzale, MD, Duke Cancer Institute, Durham, North Carolina. She is chair of the NCCN Guidelines® Panel for Colorectal Cancer Screening.

Dr Provenzale said that the NCCN "will continue to monitor" the risk-based, personalized approach to colorectal cancer screening.

The new guideline is based on research that includes a systematic review of screening trials, including new data from 3 randomized trials of one-time sigmoidoscopy. Results from those 3 trials, recently published after 15 to 17 years' follow-up, are what spurred the new guideline, which is part of the BMJ's Rapid Recommendations initiative. The journal aims to "accelerate" the creation of guidelines based on new evidence.

"It can take years for new research evidence to filter into new treatment guidelines," according to the BMJ website.

Duke's Dr Provenzale acknowledged that her NCCN panel has yet to review the sigmoidoscopy trials data but plans to do so at their next meeting, to be held November/December 2019.

The NCCN's chief executive officer, Robert Carlson, MD, countered the idea that Rapid Recommendations are the only fast-moving guideline entity.

"When scientifically significant and practice changing information emerges between the planned yearly [NCCN guideline] updates..., NCCN initiates a process to develop interim updates of the involved guideline(s)... within 2 weeks of released knowledge," he told Medscape Medical News in an email.

Consideration of Risk Factors

The new recommendations apply to men and women with no prior screening, no symptoms of colorectal cancer, and a life expectancy of at least 15 years.

In the new guide, individual cumulative risk is computed using sex, age, body mass index, physical activity, familial history, and presence of disease predisposing to colorectal cancer. Sex as a risk factor came under new scrutiny as 2 of the 3 above-mentioned sigmoidoscopy trials reported a reduction in colorectal cancer mortality and incidence with sigmoidoscopy screening in men but only a small or no reduction in women.

Most colorectal cancer screening guidelines recommend screening for everyone age 50 years and older, regardless of individual risk. At this age, the cumulative risk of developing bowel cancer over the next 15 years ranges from 1% to 7% for "most people" considered in the new guideline, said the authors.

Screening Options

The new guideline looked at evidence and made recommendations on screening for 4 screening options: fecal immunochemical test (FIT) every year, FIT every 2 years, one-time sigmoidoscopy, or one-time colonoscopy.

For individuals with an estimated 15-year risk above 3%, the panel suggests screening with any of the 4 above approaches. Because of the absence of randomized trials on FIT and colonoscopy screening, the guideline panel also used results of microsimulation models in their analysis and recommendations.

Overall, there was "substantial uncertainty" regarding the 15-year benefits and harms of screening. All 4 screening options resulted in similar colorectal cancer mortality reductions, the authors said; however, FIT every 2 years "may have little or no effect" on cancer incidence over 15 years, but FIT every year, as well as sigmoidoscopy and colonoscopy, may reduce cancer incidence, they commented. The magnitude of the benefits is dependent on the individual risk, they added.

Serious gastrointestinal and cardiovascular adverse events caused by screening are "rare," the authors noted.

The guideline authors and the editorialist agreed that the recommendations to screen are based on "weak" evidence.

"We cannot give strong recommendations for screening," summarized Dr Helsingen.

In his editorial, Dr Autier pointed out that a personalized approach is in "sharp contrast" with traditional approaches to colorectal cancer screening. He said that institutions typically give the message everyone should get screened and that not doing so endangers one's health.

"What matters is the uptake, and, to maximize uptake, messages tend to overstate benefits of screening and to downplay any undesirable consequences," Dr Autier wrote.

A personalized approach has multiple benefits, said Dr Autier. For example, prioritizing higher-risk individuals is likely to optimize screening effectiveness.

The colorectal cancer screening panel emphasized that everyone invited to screening should be able to accept or decline the invitation according to the benefits and harms they might personally expect from screening.

The MAGIC group, a nonprofit guidelines initiative, in collaboration with BMJ assembled the new panel. Panel members included patients, physicians, content experts, and methodologists. The international group hailed from Norway, the United States, Switzerland, Canada, Saudi Arabia, the United Kingdom, and The Netherlands.

Other Rapid Recommendations have included prostate cancer screening, corticosteroids for sore throat, and oxygen therapy for acute illness.

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Study Highlights

An international group of patients and healthcare providers who followed Rapid Recommendations procedures from the British Medical Journal developed the current guidelines. Panelists evaluated current literature regarding the efficacy and safety of screening for colorectal cancer, as well as the limitations of screening procedures.
The recommendation panel also used a mathematical model to further assess the benefits of specific colorectal cancer screening procedures.
The current guidelines apply to persons between the ages of 50 and 79 years with a life expectancy of ≥15 years who have not previously been screened for colorectal cancer. Moreover, the recommendations do not apply to patients at high risk for colorectal cancer (ie, personal history of colorectal cancer, inflammatory bowel disease, or genetic disorders such as Lynch syndrome).
The major innovation of the current guidelines is a risk-based approach to colorectal cancer screening. The authors advocated for the application of the QCancer 15-year colorectal risk tool before recommending a screening intervention. This instrument measures 11 different risk factors for colorectal cancer and has been demonstrated to have good validity among women and men.
The guideline provides a weak recommendation to avoid colorectal screening among adults who have a 15-year colorectal cancer risk <3%.
For adults with a 15-year risk for colorectal cancer of ≥3%, the panel recommends 1 of 4 screening modalities, which are paired here with their effect in reducing the relative risk (RR) for colorectal cancer mortality vs no screening:FIT every 2 years: RR=0.5
FIT every year: RR=0.41
Single sigmoidoscopy: RR=0.48
Single colonoscopy: RR=0.37
The RR values for colorectal cancer incidence with the 4 screening procedures vs no screening are as follows:FIT every 2 years: RR=0.95
FIT every year: RR=0.85
Single sigmoidoscopy: RR=0.73
Single colonoscopy: RR=0.66
The guidelines do not favor one method of colorectal cancer screening over another. They instead encourage shared decision making to decide on the best screening strategy for each patient.
Adherence to the screening protocol is important. With full adherence, the 4 screening options have similar effects on improving the risks for mortality because of colorectal cancer; however, FIT testing has less of an effect on reducing colorectal cancer incidence compared with sigmoidoscopy and colonoscopy.
None of the screening modalities have a substantial effect on all-cause mortality.
Recent trials of sigmoidoscopy suggest that it may have a stronger effect in reducing colorectal cancer mortality among men vs women; however, the authors of the current recommendations suggested that the differences in screening effectiveness among different subgroups are too small to necessitate separate recommendations according to sex, age, or other variables.

Clinical Implications

The lifetime risk for colorectal cancer is approximately 5% among adults living in Western countries. Most adults in the prime ages for screening have a risk for colorectal cancer between 1% and 7%. Age is certainly a major risk factor for colorectal cancer; the risk for colorectal cancer increases by 0.5% to 1.5% at 5-year intervals after age 50 years. The 5-year survival of colorectal cancer is 65%.
The current guidelines recommended a risk-based approach to colorectal cancer screening among average-risk adults between 50 and 79 years of age. The authors recommended no screening if the estimated 15-year risk for colorectal cancer is less than 3%, and FIT, sigmoidoscopy, or colonoscopy for adults at higher risk.
Implications for the Healthcare Team: The current guidelines offer a less intense approach to screening for colorectal cancer, which may be useful particularly in low-resource settings. They also are more inclusive of patient choice.

A Review of Guidelines on Colon Cancer Screenings

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