Gynecologic Surgery and Breast Cancer Risk

Women with a first-degree relative with breast cancer have twice the risk of developing breast cancer, on average, compared with other women. To assess the impact of gynecologic surgery on breast cancer risk in such women, researchers analyzed data from the Sister Study, a nationwide, prospective cohort of roughly 50,000 women aged 35 to 74 years with a biological sister with breast cancer and no breast cancer themselves at enrollment. Participants were enrolled from 2003 to 2009; more than 90% were active through 2019.

At baseline, participants reported history of gynecologic surgery (none; hysterectomy only; bilateral oophorectomy, with or without hysterectomy) as well as age and reason for procedure. Subsequent questionnaires every 2 to 3…