Bariatric Surgery Reduces Breast Cancer Incidence in a Prospective Trial

Kristensson et al build on their previous research using participants from the Swedish Obese Subjects Study (SOS), a prospective, controlled trial comparing bariatric surgery to usual care. The SOS investigators initially reported a decrease in cancer incidence after bariatric surgery in women, but not in men. Subsequently, in the cohort of women participants, they reported that bariatric surgery reduced the incidence of female-specific cancers, particularly in those women who had hyperinsulinemia at baseline. The main finding that baseline hyperinsulinemia and insulin resistance are associated with a decrease in breast cancer incidence after bariatric surgery is intriguing. However, it is not known if insulin levels or insulin resistance are true biomarkers of breast cancer risk in patients with obesity undergoing bariatric surgery, because follow-up values are not available for comparison.