Response to second-line chemotherapy in patients with hormone refractory prostate cancer receiving two sequences of mitoxantrone and taxanes
Presented in part at the 2005 Annual Meeting of the American Society of Clinical Oncology, Orlando, Florida.
Received 11 October 2005; accepted 4 January 2006.
Abstract
Objectives
Clinical trials have demonstrated a survival benefit with docetaxel chemotherapy, but limited data exist regarding the activity of second-line chemotherapy.
Methods
We retrospectively identified all patients at one institution who received at least two chemotherapy regimens for hormone-refractory prostate cancer, one mitoxantrone-based and the other taxane-based, either including docetaxel or paclitaxel. Patients were evaluated using criteria modified from the Prostate-Specific Antigen Working Group.
Results
A total of 68 patients were analyzed; 33 patients received mitoxantrone followed by taxane-based treatment, and 35 received taxane-based chemotherapy followed by mitoxantrone. The median patient age was 66 and 58 years and the median prostate-specific antigen at the start of treatment was 23 and 24 ng/mL in the mitoxantrone-first and taxane-first group, respectively. The response rates to taxane-based chemotherapy were greater whether it was used first or second (P <0.0001). Progression-free survival (PFS) was longer with taxanes than with mitoxantrone, whether used first or second (P <0.05). However, the corresponding total PFS from start of the first regimen to progression during the second regimen was similar at 39.9 and 38.7 weeks (P = 0.67). Overall survival was also not significantly different (15.2 and 17.1 months, P = 0.97). Neither age nor the interval from diagnosis to chemotherapy influenced the differences in PFS.
Conclusions
Taxane-based chemotherapy is active before or after mitoxantrone. Although PFS was longer with taxane-based chemotherapy, the total PFS and overall survival were equivalent for both sequences in this retrospective analysis, suggesting that taxane-based chemotherapy retains activity, even if delayed. Although responses were seen with mitoxantrone after taxanes, the median PFS was short, and new agents are needed after taxane-based chemotherapy.
Lank Center for Genitourinary Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts
Reprint requests: William K. Oh, M.D., Dana-Farber Cancer Institute, 44 Binney Street, Boston, MA 02115.
This work was supported by the Richard Almy Fund for Prostate Cancer, the C. Brendan Noonan, Jr Charitable Foundation, and the Arthur and Linda Gelb Center for Translational Medicine.
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