Neoadjuvant mitoxantrone and docetaxel for high-risk localized prostate cancer

Currently available treatment modalities for high-risk clinically localized prostate cancer have limited chances of achieving complete tumor elimination because of either inadequate local or metastatic tumor eradication. The goal of this phase I/II study is to evaluate the safety and efficacy of neoadjuvant docetaxel and mitoxantrone before prostatectomy.

A total of 22 men with high-risk clinically localized prostate cancer underwent weekly treatment with docetaxel (35 mg/m(2)), with increasing doses of mitoxantrone (2-5 mg/m(2)) for a 12 of 16-week treatment cycle before prostatectomy. Testosterone and prostate-specific antigen (PSA) measurements were made before and after chemotherapy.

The maximally tolerated dose for mitoxantrone was 4 mg/m(2), and the primary toxicity was neutropenia. Testosterone levels were maintained throughout treatment. PSA reductions were observed in 95% of patients, with a median reduction of 41%. The surgery was well tolerated after chemotherapy, without any major complications. Negative surgical margins were attained in 76% of patients.

Administration of multi-agent chemotherapy before prostatectomy was safe in this population. This regimen appeared to have antineoplastic activity as evidenced by PSA reductions in the absence of significant testosterone changes. The benefit of chemotherapy for improving surgical margin rates could not be determined outside of a phase III trial because the effect of patient or surgeon factors could not be dissected from the potential effect of neoadjuvant therapy. Continued study of novel agents in the neoadjuvant setting is warranted because this approach allows for the rapid identification of active agents and for molecular investigation into the mechanism of drug activity.