Colorectal cancer screening can wait until age 50

Colorectal cancer screening should wait until age 50 for average-risk, asymptomatic adults, says the American College of Physicians (ACP) in its updated guidance. However, this stands in contrast to screening recommendations by the American Cancer Society (ACS) and the US Preventive Services Task Force (USPSTF) to start at age 45.

While authors of the ACP guidance acknowledged that there has been a small increase in the incidence of colorectal cancer among individuals aged 45–49 years and a decrease in those aged 50–64 years and 65 years and older, they pointed out that the net benefit of colorectal cancer screening is much less favourable in average-risk adults between ages 45–49 compared to those between 50–75.

“Considering the potential harms that can occur with colorectal cancer screening – not to exclude cardiovascular and gastrointestinal events such as serious bleeding, perforation, myocardial infarction, and angina – unnecessary follow-ups and costs for findings are clinically unimportant,” said guideline authors led by Dr Amir Qaseem, Vice President of Clinical Policy and the Center for Evidence Reviews at ACP, and Adjunct Faculty at Thomas Jefferson University, Philadelphia, Pennsylvania, US. [Ann Intern Med 2023;176:1092-1100]

Other recommendations

For individuals aged 45–49, the ACP recommends that clinicians discuss with them the uncertainty around the benefits and harms of screening. Additionally, it advises against screening in asymptomatic average-risk adults >75 years and those with a life expectancy of ≤10 years.

According to the ACP, individuals aged 50 and older should, in consultation with their clinicians, undergo an appropriate screening test based on discussion of benefits, harms, costs, availability, frequency, patient values, and preferences.

Recommended screening tests include faecal immunochemical or high-sensitivity guaiac faecal occult blood test every 2 years, colonoscopy every 10 years, or flexible sigmoidoscopy every 10 years in addition to faecal immunochemical test every 2 years.

The ACP meanwhile advises against faecal DNA, computed tomography colonography, capsule endoscopy, urine or serum screening tests.

50 vs 45: Does age matter?

For many years, the recommendation for adults who are at average risk for colorectal cancer was to start regular colonoscopies at age 50. However, in 2021, the USPSTF advised that colorectal cancer screening should start 5 years sooner among those at average risk due to the growing cases among younger adults.

Early on in May 2021, the ACS lowered its screening recommendation to age 45. [https://www.cancer.org/cancer/types/colon-rectal-cancer/detection-diagnosis-staging/acs-recommendations.html]

The ACS defined average-risk individuals as those who do not have:

·       a personal history of colorectal cancer or certain types of polyps

·       a family history of colorectal cancer, a personal history of inflammatory bowel disease (Crohn’s disease or ulcerative colitis)

·       a confirmed or suspected hereditary colorectal cancer syndrome (familial adenomatous polyposis or Lynch syndrome), or

·       a personal history of getting radiation to the abdomen or pelvic area to treat a previous cancer.

Unlike some cancers, colon cancer can take time to develop, often 10–15 years. In the early stages of colon cancer, there are often no symptoms which makes screening important. Getting screened may increase the chances of finding, treating, and potentially surviving colon cancer.

While the age recommendation by ACP may spark debates, Dr David Rivadeneira from Huntington Hospital in Huntington, New York, US said it reinforces the message that screening saves lives.

“We have seen a striking increase in colon and rectal cancer in patients who are younger than age 50, so the issue is the age,” he said. “Should we go with 45 or 50? Being a colorectal surgeon myself and seeing patients in their 40s with colon cancer, I feel comfortable recommending screening at age 45.”

Dr Aasma Shaukat from the NYU Grossman School of Medicine in New York City, New York, US, agreed, saying that while most colorectal cancers occur after the age of 50, there is now a rising trend of colorectal cancers in those younger than 50.

Benefits vs harms

Other experts said the ACP guidance would undermine efforts to increase screening uptake in younger patients. But ACP president Dr Omar Atiq has this to say: “Choosing the right screening age will allow clinicians to help more patients.”

“When you increase the screening age without good data to show benefit you not only dilute the percentage of patients that you are able to help, but you also increase the number of people you screen who are less likely to benefit and increase their risk,” he elaborated.

Unlike the ACS and the USPSTF, the ACP took into consideration the cost of unnecessary screening, noted Dr Michael Bretthauer from the University of Oslo in Oslo, Norway, and Dr Yu-Xiao Yang from the University of Pennsylvania Perelman School of Medicine in Philadelphia, Pennsylvania, US, in a separate editorial. [Ann Intern Med 2023;doi:10.7326/M23-1695]

“The new recommendations, surprising as they may be for some, may turn the tide toward more dispassionate, evidence-based assessment of absolute benefits and harms of colorectal cancer screening,” they said.

Singapore context

In Singapore, screening begins at age 50 for individuals without any risk factors. For those at increased risk, screening is advised before age 50, depending on the risk factors present. [https://www.nuhs.edu.sg/For-Patients-Visitors/find-a-condition/Pages/Colorectal-Cancer.aspx]