Introduction: Hormone replacement therapy can diminish hormone depletion-related complaints in postmenopausal women, but is contraindicated for postmenopausal breast cancer (BC) patients. Recovery of menstruation after chemotherapy-induced amenorrhea in young hormone receptor-negative BC patients however, is accepted. To determine the safety of this strategy, we investigated the effect of recovery of menstruation on disease-free survival (DFS) and overall survival (OS) in young hormone receptor-negative BC patients treated with (neo)adjuvant chemotherapy. Methods: We selected 636 patients from a single-center cohort with early stage hormone receptornegative BC and under the age of 50 years when treated with chemotherapy. Sufficient data on course of menstruation in medical records was retrospectively found for 397 patients, of whom 299 patients (75%) had a recovery of menstruation after chemotherapy. We used Cox proportional hazards models to estimate hazard ratios (HR) for the effect of recovery of menstruation on DFS and OS. Results: Patients with recovery of menstruation after chemotherapy less frequently had lymph node involvement at diagnosis (45% vs 66%, p ¼ 0.001). After a median follow-up of 6.7 years, the adjusted hazard ratios were 1.45 (95% CI: 0.83e2.54) for DFS and 1.19 (95% CI: 0.71e1.98) for OS. Conclusion: No significantly increased recurrence risk was found for hormone receptor-negative BC patients with recovery of menstruation after chemotherapy. However, the outcome of the multivariable model is not reassuring and a potentially increased recurrence risk cannot be excluded. The results need to be validated in a larger prospective study for a more definitive answer.

Menstrual cycle, Hormone receptor-negative breast cancer, Chemotherapy, Cohort study,
The Breast
Department of Medical Oncology

van Barele, M., Heemskerk-Gerritsen, B.A.M, van Doorn, H.C, Schmidt, M.K, Hooning, M.J, & Jager, A. (2020). The impact of menstruation persistence or recovery after chemotherapy on survival in young patients with hormone receptor negative breast cancer. The Breast, 52, 102–109. doi:10.1016/j.breast.2020.05.004