Adjuvant combination chemotherapy with cyclophosphamide, methotrexate, and fluorouracil was administered after radical mastectomy for primary breast cancer with histologically positive axillary lymph nodes to assess whether it would improve treatment outcome as compared with surgery alone. Here we report a 20-year follow-up of this investigation.

In 1973 we began a trial involving 386 women who were randomly assigned to receive either no further treatment after radical mastectomy (179 women) or 12 monthly cycles of adjuvant combination chemotherapy (207 women). All patients were admitted to the Istituto Nazionale Tumori in Milan, Italy. Adjuvant chemotherapy was delivered in the outpatient clinic of the Division of Medical Oncology.

After a median follow-up of 19.4 years, the patients given adjuvant combination chemotherapy had significantly better rates of relapse-free survival (unadjusted relative risk of relapse, 0.71; 95 percent confidence interval, 0.56 to 0.90; P = 0.004; adjusted relative risk, 0.65; 95 percent confidence interval, 0.51 to 0.83; P<0.001) and total survival (unadjusted relative risk of death, 0.78; 95 percent confidence interval, 0.62 to 0.99; P = 0.04; adjusted relative risk, 0.76; 95 percent confidence interval, 0.60 to 0.97; P = 0.03). With the exception of postmenopausal women, a benefit from adjuvant chemotherapy was evident in all subgroups of patients.

The long-term results of this trial of adjuvant combination chemotherapy confirm our preliminary observations of the effectiveness of the treatment in women with node-positive breast cancer.