Optimal Timing of Breast Cancer Surgery Within Menstrual Cycle

The Abramson Cancer Center of the University of Pennsylvania
Last Modified: May 20, 1996

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Mark Norman Levine, M.D., Ontario Cancer Foundation, Hamilton University and professor of medicine, McMaster University, National Cancer Institute of Canada Clinical Trials Group (Kingston, Ontario, Canada), presented a study which examined the relationship between the timing of breast cancer surgery during the menstrual cycle and the risk of breast cancer recurrence.

The results of previous studies relating the timing of breast cancer surgery during the menstrual cycle to breast cancer recurrence have been inconsistent. Some studies have suggested increased recurrence rates if the surgery was performed during the first 14 days following the onset of menses (follicular phase) compared to the second part of the cycle (luteal phase). Although these studies were retrospective and small in size, some women have chosen to have their surgery during the luteal phase of the menstrual cycle (i.e., 14-30 days following the onset of mensen).

Between December 1989 and July 1993, the National Cnacer Institute of Canada Clinical Trials Groupd conducted a trial comparing two different chemotherapy regimens in premenopausal women with node positive breast cancer. In these women, the relationship between timing of surgery and breast cancer recurrence was examined. Of the 107 patients whose primary surgery was during the luteal phase, 31 (29%) developed recurrence compared with 24 of 214 (19%) whose surgery was during the follicular phase. Day 8 of a 28 day cycle was calculated to be the optimal time for surgery.

"In contrast to other studies, this is the first study to show that there is an increased risk of breast cancer recurrence if surgery is performed during the latter part of the menstrual cyc (days 14-30), compared to the earlier part of the cycle," Patricia Braly, M.D., professor and chief, Department of Pbstetrics and Gynecology, LSU Medical Center (New Orleans, LA), said at a press briefing today.