Colorectal cancer is a disease in which cells in the colon or rectum grow out of control. Sometimes abnormal growths, called polyps, form in the colon or rectum. Over time, some polyps may turn into cancer. Also colorectal adenomas that persist and grow for long periods can become malignant.
Not counting some kinds of skin cancer, colorectal cancer is the third most common cancer in men and women. It is also the third leading cause of cancer-related deaths in the United States.
Obesity is a known risk factor of colorectal cancer. However the impact of weight change on colorectal adenoma risk is less clear and could have important implications in disease prevention.
In a recently published study, researchers evaluated weight change in adulthood and incident colorectal adenoma. The findings appear in the Journal of the National Cancer Institute Spectrum.
The study assessed weight change during early-late (age 20 to baseline), early-middle (20-50 years), and middle-late (50 years) using self reported weight data in relation to incident distal adenoma in Prostate, Lung, Colorectal and Ovarian Cancer Screening Trials (PLCO).
The study took data from 154,942 men and women from the PLCO study and selected 18,588 participants for their analysis.
The average age at trial entry in both the incident colorectal adenoma and control groups was approximately 62 years. Controls tended to consume more fiber, fewer calories, and less red meat than cases. A higher proportion of cases (67.1%) than controls (55.3%) was male. Cases had statistically significantly higher BMI at age 50 years than controls.
The researchers found that weight loss from early-late adulthood, particularly among those who were initially overweight or obse, was associated with a statistically significantly reduced adenoma risk. The results are also consistent with a previous study that observed a lower likelihood of adenoma following bariatric surgery, suggesting a beneficial effect of weight loss on adenoma risk in an initially obese population.
The researchers found that losing weight from early to late adulthood, at least 1 pound every 5 years, was associated with a 46% reduced risk of developing colorectal adenoma, which once more shows us the importance of having an adequate weight, and of weight loss in those overweight or obese.
Shisi Me, et al. Weight Change and Incident Distal Colorectal Adenoma Risk in the PLCO Cancer Screening Trial. JNCI Can Spec. 2022. https://doi.org/10.1093/jncics/pkab098