['In cancer patients, correlation between response to chemotherapy and gain in survival remains debated. We addressed this question in a multivariate analysis evaluating response to chemotherapy as a factor influencing survival of patients with metastatic breast cancer.', 'From 1977 to 1992, 1430 patients included in eight consecutive prospective trials of anthracycline-based first-line chemotherapy in metastatic breast cancer, were available for assessment. Median follow-up was 155 months.', "Median survival from the date of randomisation was 24 months. Objective response rate was 63.6%. A complete response (CR) was achieved in 17% (249 patients). In a stepwise forward progression analysis objective response was the first independent prognostic factor for survival. Median survival time was 43 months for complete responders (CR), 29 months for partial responders (PR), 18 months for stable disease (SD), 5 months for progressive disease (PD). The probability of survival at 5 and 10 years was 35% and 15% for CR's and decreased to 18% and 6% for PR's. The timing of best response (at 4 or 8 months) was not related to outcome."] Is response to chemotherapy a major parameter-influencing long-term survival of metastatic breast cancer patients?