Timing of surgery in relation to the menstrual cycle in premenopausal women with operable breast cancer.

Recent studies have suggested that the timing of surgery in relation to the menstrual cycle might influence survival of premenopausal women with operable breast cancer. The data of 96 premenopausal patients who underwent primary surgery for operable breast carcinoma between 1975 and 1988 were analysed. At 10 years, disease-free and overall survival rates of patients whose initial surgery was 1-12 days after the starting date of the last menstrual period (follicular phase) were significantly poorer compared with survival of those who underwent operation more than 12 days after the last menstruation (luteal phase) (disease-free survival rate 40 versus 72 per cent, P = 0.002; overall survival rate 40 versus 79 per cent, P = 0.001). These differences in survival remained significant in a second analysis based on the menstrual phase at the time of both initial and definitive operation. Menstrual phase had the greatest impact on the survival of patients with positive axillary nodes (P = 0.009). Prospective studies are required to elucidate the relationship between the timing of all surgical procedures during the menstrual cycle and survival.