Background: The aim of this retrospective study was to determine those prognostic factors associated with response to a second-line chemotherapy in patients with metastatic breast carcinoma (MBC) that was previously responsive to a first-line chemotherapy.
Methods: The 70 MBC patients studied had previously responded to a first-line chemotherapy, mainly anthracycline or anthracenedione-containing regimens. During first-line chemotherapy they had received treatment until the maximum response was obtained, at which time treatment was discontinued. Second-line chemotherapy regimens were of several types (48.5% with anthracycline). A study of prognostic factors associated with response to second-line chemotherapy was performed by univariate and multivariate analysis.
Results: Second-line chemotherapy achieved a 44% response rate, with a median response duration of 10 months. Survival was 13 months in the entire patient group, 22 months in responders, and 8 months in nonresponders. Univariate analysis identified seven factors related to patient response rate to second-line treatment. A better response rate to second-line chemotherapy was observed in patients with the following features: 1) chemotherapy free time (time between onset of metastatic disease and initiation of first-line) < 12 months (P = 0.03); 2) complete response to first-line chemotherapy (P = 0.013); 3) response duration to first-line chemotherapy > 14 months (P = 0.0001); 4) progression free interval (time between end of first-line treatment and initiation of second-line chemotherapy) > 11 months (P = 0.0001); 5) performance status at second-line treatment < 2 (P = 0.04); 6) tumor index at second-line chemotherapy < 4 (P = 0.05); and 7) treatment with an anthracycline-containing second-line regimen (P = 0.03). In multivariate analysis, only progression free interval was identified as being associated with response rate to second-line chemotherapy (P = 0.0001).
Conclusions: Retained chemosensitivity appeared to be an important characteristic in patients responding to second-line chemotherapy.