Impact of chemotherapy beyond the first line in patients with metastatic breast cancer

Purpose The goal of this study was to determine which benefit could be brought by the succession of chemotherapy lines in patients treated for metastatic breast cancer and to identify patients who benefit from these treatments. Patients and methods Nine hundred and thirty four patients with metastatic breast cancer diagnosed between 1992 and 2002 were studied. A total of 772, 505, 283, 127 and 55 patients received a first, second, third, fourth and fifth line of chemotherapy, respectively. The evaluation of benefit in each chemotherapy lines was based on time of disease control (TDC). TDC is defined as time between the date of the beginning of treatment and the date of progression of disease or death. In case of early progressive disease or progression diagnosed at the first evaluation, TDC value is zero. Cox proportional hazards model was used to identify factors that could influence the TDC in each line of chemotherapy. Results Medians duration of TDC are 9.3 [0-120], 5.9 [0-83.6], 4.63 [0-37.2], 4.1 [0-36.7] and 0.23 months [0-15] in first, second, third, fourth and fifth lines, respectively. More interestingly, TDC was longer than 6 months in 50.5% of patients treated with second line, 40% with third line, 35% with fourth line and 23.5% with fifth line. These results justify the therapeutic succession of chemotherapy lines in metastatic breast cancer. Only one factor influences the duration of TDC for each line of treatment: duration of TDC observed in the previous line.