Timing of breast cancer surgery within the menstrual cycle: influence on lymph-node involvement, receptor status, postoperative metastatic spread and local recurrence.

Prompted by a report of Hrushesky et al. stating that women operated upon for breast cancer during their perimenstrual period showed a higher risk for developing future metastases than women operated upon during their mid-cycle, we examined the patients with breast carcinoma who were treated at the Gynaecological University Hospital Zürich between 1971 and 1988 with respect to the influence of menstrual cycle phase on certain factors. 104 patients underwent perimenstrual surgery, i.e., between days 1 and 6 or days 21 and 36 of the cycle. 120 women had mid-cycle surgery (i.e., days 7-20 of the cycle). In contrast to the experience of Hrushesky et al., we found no significant differences in the survival curves. The same was true when the proliferative phase (days 1-14; n = 109) was compared with the secretory phase (days 15-32; n = 108). We tested the different groups for homogeneity and found that 54% of the patients with perimenstrual surgery showed axillary lymph node involvement, whereas in the midcyclic group only 38% showed positive nodes. We have no plausible explanation for this difference. These findings indicate that there might be certain cycle-related differences with respect to lymph node status but that they do not affect survival. Hence, timing surgery to the menstrual cycle is not mandatory for the time being.