The Relationship between Surgery and Phase of the Menstrual Cycle Affects Survival in Breast Cancer

The impact of time of surgery based on the menstrual cycle is a controversial issue. Two decades after the first interest in this topic, a number of studies with conflicting results have not helped to resolve this problem. This study aimed to prospectively evaluate the impact of timing of surgery based on the menstrual cycle on survival rates of breast cancer patients, and various clinical and hormonal classifications of the menstrual cycle were compared in order to determine the phase of the menstrual cycle which showed the highest degree of surgical survival.

Premenopausal breast cancer patients treated with curative surgery between 1998 and 2002 were prospectively included in this study. Patients were divided into different groups according to the first day of their last menstrual cycle using three different classifications (clinical, Hrushesky, Badwe), and were also grouped according to their serum hormone levels. Serum levels of follicle stimulating hormone, luteinizing hormone, estrogen, and progesterone were measured on the day of surgery.

Ninety patients were included in the study. Median follow-up time was 90 months. Nineteen patients (21.1%) had loco-regional recurrence and/or distant metastases while 12 patients (13.3%) died during follow-up. Five-year (78.6% vs. 90.6%) and 10-year (66.7% vs. 90.6%) disease-free survival (DFS) rates of patients in the clinically defined follicular phase were significantly decreased compared to luteal phase. On the other hand, hormonally determined phases of the menstrual cycle and grouping of patients according to clinical classifications did not show an impact on prognosis.

In the current study performing surgery in the follicular phase of the menstrual cycle decreased DFS in premenopausal patients. According to these results, performing surgery during the luteal phase of the menstrual cycle might have a beneficial effect on survival.