Can weight loss in adulthood reduce the risk of developing colorectal adenomas?

March 2022.

While obesity is a known risk factor for colorectal cancer (CRC), the impact of weight change on the development of adenomas, a type of precancerous polyp, is not well understood. A new study published in JNCI Cancer Spectrum found that weight loss among adults, particularly for those who are overweight or obese, may reduce their risk of developing adenomas. The researchers found that losing at least two pounds per decade from early to late adulthood until the mid-70s reduced an individual’s risk for developing adenomas by 46%. Among individuals who were overweight or obese at age 20, weight loss was associated with a more than 60% reduction in risk.

The Study

The researchers evaluated 17,629 participants from the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening trial who had available weight data, reported no history of colorectal polyps or other predisposing colon conditions, had received a negative screening test result for polyps or CRC at the start of the trial, and received a follow-up sigmoidoscopy 3-5 years later. Weight loss in adulthood was linked to reduced adenoma risk, whereas weight gain greater than 3kg every 5 years increased risk. These findings underline the important of maintaining a healthy weight throughout adulthood to prevent colorectal adenomas.

Take away message:

Weight loss in adults, particularly among those who are overweight or obese, appears to reduce the risk of developing adenomas, a type of precancerous growth that may become colorectal cancer.