Are men aged below 50 at risk of colon and rectal cancer? US task force says screening should start at 45
Screening people for colon and rectal cancer should start at 45, five years earlier than the current recommended age of 50, according to a proposal by US Preventive Services Task Force (USPSTF). The independent panel of experts found that colorectal cancer screening saves lives and adults aged 45 to 75 should be screened. Colorectal cancer starts in the colon or the rectum. These cancers can also be called colon cancer or rectal cancer, depending on where they start.
“For adults aged 45 to 49 years, the USPSTF found adequate evidence that screening for colorectal cancer with several different methods can accurately detect early-stage colorectal cancer and adenomatous polyps. The USPSTF found adequate evidence that screening for colorectal cancer with stool tests, colonoscopy, CT colonography or flexible sigmoidoscopy in adults aged 45 to 49 years provides a moderate benefit in terms of reducing colorectal cancer mortality and increasing life-years gained," says the draft recommendation.
The document is available for review and public comment from October 27 through November 23, 2020. Along with it, the draft evidence review and draft modeling report have also been posted online.
What do the numbers say?
Colorectal cancer is the third leading cause of cancer death for both men and women, with an estimated 53,200 people dying from colorectal cancer in the US in 2020. The American Cancer Society (ACS) estimates 104,610 new cases of colon cancer in the US in 2020, and 43,340 new cases of rectal cancer. Overall, the lifetime risk of developing colorectal cancer is about 1 in 23 (4.4%) for men and 1 in 25 (4.1%) for women.
Colorectal cancer is most frequently diagnosed among people aged 65 to 74 years. It is estimated that 10.5% of new colorectal cancer cases occur in people younger than age 50 years. In 2016, about one-quarter of eligible adults in the US had never been screened for colorectal cancer.
Black adults have the highest incidence of and mortality from colorectal cancer compared to other races/ethnicities. From 2013 to 2017, incidence rates for colorectal cancer were 43.6 cases per 100,000 Black adults, 37.8 cases per 100,000 White adults, 31.8 cases per 100,000 Asian/Pacific Islander adults, 39 cases per 100,000 American Indian/Alaska Native adults and 33.7 cases per 100,000 Hispanic/Latino adults. Colorectal cancer death rates were 18.5 deaths per 100,000 Black adults, 13.6 deaths per 100,000 White adults, 9.6 deaths per 100,000 Asian/Pacific Islander adults, 15.8 deaths per American Indian/Alaska Native adults and 11.1 deaths per 100,000 Hispanic/Latino adults.
The proposed draft
In 2016, the USPSTF recommended screening for colorectal cancer starting at age 50 and continuing until age 75. The current proposal is based on emerging data that indicates that there has been a rising risk for colorectal cancer among younger adults, aged 45 to 49 years. According to the task force, recent epidemiological data suggest that colorectal cancer incidence in 45-year-old adults now approaches that of persons aged 50 years in the era before the introduction of routine screening. This rising risk received global attention recently when ‘Black Panther’ actor Chadwick Boseman died of colon cancer in August. He was 43.
“Age is one of the most important risk factors for colorectal cancer, with incidence rates increasing with age, and nearly 94% of new cases of colorectal cancer occurring in adults age 45 years and older. Rates of colorectal cancer are higher in Black adults, persons with a family history of colorectal cancer (even in the absence of any known inherited syndrome such as Lynch syndrome or familial adenomatous polyposis), and men. However, all adults age 45 years and older are at risk for colorectal cancer and should be offered screening, even if these risk factors are absent,” explain authors.
The panel has proposed an ‘A’ recommendation for colorectal cancer screening in all adults aged 50 to 75 years, and a ‘B’ recommendation for screening adults aged 45 to 49, and ‘C’ for those aged 76 to 85 years. “The USPSTF concludes with high certainty that the net benefit of screening for colorectal cancer in adults ages 50 to 75 years is substantial. The USPSTF concludes with moderate certainty that the net benefit of screening for colorectal cancer in adults ages 45 to 49 years is moderate,” suggests the proposal.
Further explaining, the experts say that while the absolute risk of developing colorectal cancer is much lower in adults younger than age 50 years — 20.0 new colorectal cancer cases per 100,000 persons aged 40 to 49 years, 47.8 new cases per 100,000 persons aged 50 to 59 years, and 105.2 new cases per 100,000 persons age 60 years and older — age-period-cohort analysis indicates a recent trend for increasing risk of colorectal cancer in adults younger than age 50 years. "Additionally, modeling performed by the Cancer Intervention and Surveillance Modeling Network (CISNET) suggests that starting colorectal cancer screening at age 45 years can moderately increase life-years gained and decrease colorectal cancer cases and deaths compared to beginning screening at age 50 years," they add.
ACS had suggested lowering the age earlier
This is not the first time that screening for colon and rectal cancer at age 45 has been proposed. In 2018, the ACS updated its guidelines to recommend colorectal cancer screening at 45.
"The American Cancer Society 2018 guideline for colorectal cancer screening recommends that average-risk adults aged 45 years and older undergo regular screening with either a high-sensitivity stool-based test or a structural (visual) exam, based on personal preferences and test availability. As a part of the screening process, all positive results on non-colonoscopy screening tests should be followed up with timely colonoscopy,” said the advisory.