Background: A prospective, multicenter, randomized, Phase III trial comparing the efficacy of combination chemotherapy with 5-fluorouracil, doxorubicin, and cyclophosphamide (FAC) with a combination of vinorelbine and doxorubicin (NA) in the treatment of patients with advanced breast carcinoma was undertaken.
Methods: One hundred and seventy-seven patients who previously were untreated for recurrent or metastatic breast carcinoma were entered into the study; 7 patients could not be assessed. The final analysis relates to 85 patients who were treated with FAC and 85 patients who were treated with NA, of whom 21 (25%) and 44 (52%), respectively, had received prior adjuvant chemotherapy.
Results: The overall response rates were similar for the two treatments and were unaffected by prior exposure to adjuvant therapy; overall response rate (ORR) for FAC was 74% (95% confidence interval [95% CI], 65-83%), and the ORR for NA was 75% (95% CI, 66-84%). The activity of NA in patients with liver involvement was greater than that of FAC in terms of survival. Overall survivals were similar, with a median of 17.3 months for patients receiving FAC and 17.8 months for patients receiving NA. Severe toxicity was uncommon with World Health Organization Grade 3-4 neutropenia affecting only 7% of patients in each arm of the study. NA was associated with a higher incidence of mild to moderate constipation, neurotoxicity, and phlebitis, whereas FAC produced a slight excess of mild cardiotoxicity.
Conclusions: The efficacy of these two regimens is very similar, although NA may be more active in a subset of patients with visceral metastatic disease, particularly liver involvement. It is clear that, in a direct comparison with an established three-drug regimen, the newer two-drug combination of NA demonstrated equivalent activity with no significant excess of Grade 3-4 toxicity.