Response rates of taxane rechallenge in metastatic breast cancer patients previously treated with adjuvant taxanes.

Purpose: This study was conducted to determine the efficacy of taxane-based regimens in patients with metastatic breast cancer pre-treated with taxanes in adjuvant treatment and also to assess the response rates of taxanes in each treatment line. Methods: The data of 939 breast cancer patients, who had received adjuvant taxane-based chemotherapy, were reviewed retrospectively. In 191 of them local/distant recurrences were detected. The treatments that were given when metastases occurred and the responses were recorded. Response rates (RRs), clinical benefit rates/CBR (complete response/CR + partial response/PR + stable disease/SD) and progression-free (PFS) and overall survival (OS) values were determined. RRs to the most frequently used protocols in our institutes (capecitabine-based and taxane-based regimens) were compared. Results: Of 191 patients, 11 didn't receive treatment and for the remaining 180 patients 45 (24%) received taxane-based therapies, 89 (49.4%) received capecitabine-based therapies, 28 (15.6%) received hormonotherapy and 18 (10%) received other chemotherapeutics. The RR for first-line taxane regimen was 58.5%, consisting of 5 CRs (12%) and 19 PRs (46%). Menopausal status, histological grade, estrogen/progesterone receptors, cerbB2 status, having PFS > ors 2 years and the site of metastases did not predict response to first-line taxane treatment. For the 2nd and 3rd or later line therapies, RRs of taxane rechallenge were above 40%. Conclusion: Rechallenging with taxanes after (neo)adjuvant taxane exposure seems to be a reasonable option even in 3rd or further line treatments with high response rates.