Although colorectal cancer is associated with obesity, it is unclear if weight loss surgery impacts the incidence of these tumors. Results from a new study published in the International Journal of Cancer suggest that the risk of colon cancer may be increased in individuals who have undergone such surgery.

In the population-based study of 502,772 individuals with obesity from five Nordic countries, patients who underwent weight loss surgery had a higher risk of colon cancer than the general population.

This risk seemed to increase over time, and it exceeded the elevated risk of obese individuals without such surgery. The association between weight loss surgery and rectal cancer was weaker, but it tended to increase with longer follow-up.