The response to further chemotherapy in patients with carcinoma of the breast who progressed while receiving adjuvant therapy.

The effect of known chemotherapeutic programs in patients with breast cancer who developed metastasis during or after adjuvant chemotherapy with L-PAM plus 5-FU (PF) were studied. Thirteen patients failed while receiving adjuvant therapy at 3-22 months from the time therapy started. Three patients failed 6-28 months after 2 years of therapy. Thirteen patients received PF followed by cyclophosphamide, methotrexate, and 5-fluorouracil (CMF) at the time of progression on PF. Of these, ten received Adriamycin and vincristine (AV) at the time of progression on CMF. The response to CMF was 7%. No patient responded to AV after progression on CMF. Two of three patients treated with AV after failure on PF did respond, but both for only 6 months. This suggests that adjuvant therapy may render the tumor less responsive to further chemotherapy. Since most patients failed while on adjuvant therapy, this may indicate a poor prognosis regardless of the agents used.