Preliminary 3-year results of 12 versus 6 cycles of surgical adjuvant CMF in premenopausal breast cancer.

In hope of reducing the duration of adjuvant treatment in premenopausal patients with operable breast cancer and histologically positive axillary lymph nodes, a prospective controlled study was started in September 1975. A total of 160 patients were randomized to receive 12 cycles of adjuvant CMF, while 165 were allocated to receive 6 cycles. At 3 years from radical mastectomy, the relapse-free survival was 85.4% in the 12-cycle group compared to 82.6% for the 6-cycle subset (P = 0.29). In both treatment groups, the incidence of treatment failure was directly proportional to the number of involved axillary nodes and to the clinical tumor size. Drug-induced amenorrhea as well as estrogen receptor status failed to significantly affect the results obtained. Treatment failures were more often documented in distant sites, while only 4--5% relapse was observed in local-regional areas. Overall survival was also similar for both treatment arms (86.2% vs. 85.1%, P = 0.49). Toxicity was moderate and reversible and no drug-induced neoplasms were so far observed. Present results achieved with 6 cycles of adjuvant CMF appear encouraging. However, they are still too preliminary to recommend the routine use of 6 cycles instead of the classical 12 cycles.