Current status of Milan adjuvant chemotherapy trials for node-positive and node-negative breast cancer

This report summarizes the most important clinical results achieved at the Milan Cancer Institute through various randomized trials with systemic adjuvant chemotherapy. In the study testing surgery versus surgery plus 12 cycles of cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) in node-positive patients, the reduction in failure rate (34%) significantly favored CMF-treated patients (P less than 0.001). Despite a reduction in the death rate of 23%, the overall survival showed only a trend for CMF compared to surgery alone (P = 0.10). In a second study, the 8-year results confirmed the lack of difference in relapse-free survival and total survival rates between patients who received 12 and 6 cycles of CMF. The third study indicated that at 6 years, postmenopausal women who had 1-3 positive lymph nodes and were treated with full-dose sequential non-cross-resistant combinations had rates of relapse-free survival and total survival that were superior to those previously achieved with CMF in the same menopausal subset. In a limited series of patients with negative axillary nodes as well as negative estrogen receptors, there was clear evidence of very poor prognosis in women given only local-regional therapy, compared to women treated with adjuvant CMF. Within the node-negative subset, the proliferative activity (labeling index) of the primary tumor appears to be a more effective prognostic discriminant than estrogen receptor status. The proportion of primary drug-resistant tumor cells as well as the lack of relative dose intensity in the drug programs tested so far probably represent the two most important causes for the failure of adjuvant chemotherapy.(ABSTRACT TRUNCATED AT 250 WORDS)