Intensification of adjuvant chemotherapy: 5-year results of a randomized trial comparing conventional doxorubicin and cyclophosphamide with high-dose mitoxantrone and cyclophosphamide with filgrastim in operable breast cancer with 10 or more involved axillary nodes.

Abstract

To determine whether intensifying the dose of adjuvant chemotherapy improves the outcome of women with primary breast cancer and 10 or more involved axillary nodes. Patients (n = 150) were randomized to receive either four cycles of standard doxorubicin 60 mg/m(2) plus cyclophosphamide 600 mg/m(2) every 3 weeks (arm A) or four courses of intensified mitoxantrone 23 mg/m(2) plus cyclophosphamide 600 mg/m(2), with filgrastim 5 g/kg/d from days 2 to 15, every 3 weeks (arm B). Disease-free survival (DFS), distant disease-free survival (DDFS), and overall survival (OS) were determined using life-table estimates. There were no significant differences in DFS (P =.44), DDFS (P =.67), or OS (P =.99) between the two groups at 5 years; DDFS was 45% (arm A) versus 50% (arm B), and DFS was 41% versus 49%, respectively. Five-year survival was similar in both arms (61% v 60%, respectively). Failure to note an intergroup difference in outcome was unrelated to relative dose-intensity. Analysis of patients with 15 or more positive nodes revealed a significant difference in 5-year DDFS (19% v 49% in arm B; P =.01). Toxicity was generally mild in both groups, with no toxic death. The incidence of febrile neutropenia was low (0.3% v 3%). Alopecia was less frequent in arm B (P <.001). This randomized trial confirms the feasibility of administering mitoxantrone 23 mg/m(2) with cyclophosphamide and filgrastim. Although there was no significant difference between conventional and intensified arms at 5 years, according to subgroup analysis, intensified treatment may decrease the risk of relapse in patients with 15 or more positive nodes compared with doxorubicin an cyclophosphamide.