[Prognosis of patients with breast cancer related to the timing of operation during menstrual cycle: a report of 218 patients].

We have finished a retrospective study of 218 premenopausal patients who underwent primary surgery for operable breast carcinoma between March 1958 and December 1984. All these patients had available records of menstrual data and had been followed-up for more than 10 years. U-nivariate analysis showed that the menstrual timing of operation, as other known prognostic factors (tumor size, node status, histological grade, TNM classification, adjuvent systemic therapy, etc), had an influence on the patients' outcome. Multivariate analysis by Cox regression model indicated that disease-free rate and overall survival rate of patients operated during the periovulatory phase (days 7-20, 123 cases) were significantly superior to those during the perimenstrual phase (days 1-6 and 21-40, 95 cases) (P < 0.01). There were no significant differences in prognosis between patients who received their operations during the follicular phase (days 4-14, 96 cases) and those during the luteal phases (days 15-40, 122 cases) (P > 0.1). We suggest that the adequate timing of operation should be further determined by prospective, randomized clinical study.