First- and second-line chemotherapy with docetaxel or mitoxantrone in patients with hormone-refractory prostate cancer: does sequence matter?

BACKGROUND Docetaxel and mitoxantrone are considered first-line chemotherapeutic options in patients with hormone-refractory prostate cancer (HRPC), but their clinical effectiveness in a second-line setting is unknown. Therefore, the authors conducted a population-based retrospective study to establish activity and tolerability of second-line docetaxel or mitoxantrone in HRPC. METHODS The study included 68 patients who had failed androgen ablation therapy and who received docetaxel and mitoxantrone in either sequence. Clinical efficacy in terms of median overall survival (OS), progression-free survival (PFS), posttreatment prostate-specific antigen (PSA) decline of ≥ 50% and treatment-related toxicity were evaluated. RESULTS Of 68 patients, 35 received docetaxel followed by mitoxantrone, and 33 received mitoxantrone followed by docetaxel. Both groups were comparable for recognized pretreatment prognostic factors. Patients who received docetaxel first-line had a trend toward longer median OS compared with patients treated with second-line docetaxel after mitoxantrone failure (22 mos, 95% confidence interval [CI], 17.2–26.8 mos vs. 15 mos, 95% CI, 10.4–19.6 mos). Median number of second-line chemotherapy cycles was 3 and median PFS survival was 2–3 months in both groups. Second-line docetaxel produced a higher PSA response compared with mitoxantrone (38% vs. 12%, P = 0.012), but this did not translate to a survival benefit. Both second-line docetaxel and mitoxantrone were associated with a high frequency of treatment-related adverse events that resulted in dose reduction, delay, or discontinuation (64% and 46% of patients, respectively). CONCLUSIONS Study results favored docetaxel given up-front for patients with HRPC considered suitable for further chemotherapy. Second-line docetaxel or mitoxantrone had limited efficacy and tolerability. Patients who are candidates for second-line chemotherapy, should be enrolled into clinical trials. Cancer 2006. © 2006 American Cancer Society.