Delayed premature menopause following chemotherapy for early stage breast cancer: Long-term results from IBCSG Trial V

687 Background: The likelihood of delayed, but nevertheless premature, menopause following chemotherapy has not been thoroughly explored in women who remain premenopausal immediately following adjuvant chemotherapy for breast cancer. Methods: We evaluated the age of menopause in women with early stage breast cancer who remained premenopausal using data from the International Breast Cancer Study Group (IBCSG) Trial V. From 1981–1985, 1407 premenopausal women were randomized by nodal status: 692 with node-neg disease received either no systemic therapy (NC) or CMFx1 preoperatively (Cp); 715 with node-pos disease received either Cp, CMFx6 postoperatively (CT), or CT+Cp. Median follow-up is over 19 years. Results: Women who reported no menses during 12–24 months after enrollment (N=660), history of hysterectomy (N=15) or oophorectomy (N=7), or missing 12–24 month menses data (N= 53) were excluded, leaving 672 women in the following age at diagnosis groups: < 35 years (N=96), 35–39 years (N=154), and 40–44 yea...