Screening before 50 reduces risk of colorectal cancer in women

Women who are screened for colorectal cancer before the age of 50 have a significantly reduced risk of the cancer compared to those who have no endoscopic screening or decide to initiate testing at age 50, according to a new study from Massachusetts General Hospital.

Researchers found a 50 to 60 percent lower risk of colorectal cancer among women who started endoscopy (colonoscopy or sigmoidoscopy) screening at age 45 compared to those who had not undergone screening at all.

In addition, they learned that starting screening at ages 45 to 49 resulted in a significant reduction in the women’s actual cases of colorectal cancer diagnosed through age 60, compared to a strategy in which women began screening at ages 50 to 54. While the study was focused on women, Andrew T. Chan who led the study suggests the same benefits likely accrue to men, though he adds further studies are needed.

The study looked at the more than 78,000 women in the Nurses’ Health Study who had a colonoscopy or sigmoidoscopy between 1991 and 2017. These findings support recommendations from the American Cancer Society and the US Preventive Services Task Force over the past four years to commence screening at age 45 to address the steady increase in cases of younger-onset colorectal cancer.

• See “Starting screening before age 50 is found to significantly reduce the risk and incidence of colorectal cancer in women” by Katie Marquedant on the Massachusetts General Hospital website (May 5, 2022)
• See the abstract of the scientific paper “Age at Initiation of Lower Gastrointestinal Endoscopy and Colorectal Cancer Risk Among US Women” by Wenjie Ma et al.