Retrospective cohort study of the association of obesitas with risk of recurrence of postmenopausal HR-positive breast cancer treated with aromatase inhibitors

Obesity is a risk factor for recurrence in postmenopausal women with HR-positive breast cancer. Evidence suggests that women with obesity do not obtain similar protection from aromatase inhibitors (AIs) as women with healthy weight. A nationwide retrospective study in Denmark found that among 13,230 postmenopausal patients with HR-positive breast cancer treated with AIs, 1587 patients had a recurrence over median 6.2 years of follow-up. The risk of recurrence increased with increasing body mass index at diagnosis, with a significantly elevated risk among women with obesity (aHR 1,18; 95% CI 1,01-1,37) or severe obesity (1,32; 1,08-1,62).