Mechanism of action of adjuvant chemotherapy in early breast cancer.

The relation between tumour oestrogen and progesterone receptor status, menstrual status, relapse-free survival, and overall survival was analysed in 411 patients with early breast cancer randomised to receive either postoperative adjuvant chemotherapy with cyclophosphamide, methotrexate, and fluorouracil (CMF) or no additional treatment (control). Prolongation of time to recurrence and survival was seen predominantly in premenopausal patients; these effects were seen only with tumours positive for steroid receptors, particularly progesterone. Chemotherapy led to permanent amenorrhoea in 61% of premenopausal patients. The therapeutic effects of chemotherapy were seen only when CMF induced permanent amenorrhoea in premenopausal patients. These findings support the hypothesis that the effect of adjuvant chemotherapy in early breast cancer may be mediated by ovarian suppression.

RCT Entities:   Population Interventions Outcomes