Future directions in the treatment of androgen-independent prostate cancer

Area of Science:

• Oncology
• Medical Research
• Clinical Trials

Background:

• Hormone-refractory prostate cancer (HRPC) presents challenges in treatment due to chemotherapy resistance.
• Preclinical data suggest taxanes, like docetaxel, are effective against HRPC by inhibiting the antiapoptotic gene bcl-2.
• Early trials indicated docetaxel and its combination with estramustine show promise for improving survival in HRPC.

Purpose of the Study:

• To compare the efficacy of docetaxel-estramustine versus mitoxantrone-prednisone in men with HRPC.
• To evaluate the impact of these treatment regimens on overall survival, progression-free survival, and prostate-specific antigen (PSA) response.
• To assess the toxicity profiles of the two treatment arms.

Main Methods:

• A phase III intergroup trial (SWOG 9916) enrolled 684 eligible patients with HRPC.
• Patients were randomized to receive either docetaxel-estramustine or mitoxantrone-prednisone.
• Outcomes measured included median survival, progression-free survival, PSA response rates, and toxicity.

Main Results:

• Docetaxel-estramustine significantly improved median survival (17.5 vs. 15.6 months, P = .02), reducing the relative risk of death by 20%.
• Progression-free survival was substantially longer with docetaxel-estramustine (6.3 vs. 3.2 months, P < .001).
• A significantly higher proportion of patients on docetaxel-estramustine achieved at least a 50% decline in PSA (50% vs. 27%, P < .001), though toxicity was more frequent.

Conclusions:

• Docetaxel-estramustine is a superior treatment option for HRPC compared to mitoxantrone-prednisone, offering improved survival and disease control.
• While associated with increased toxicity, the benefits of docetaxel-estramustine warrant its consideration in HRPC treatment.
• Ongoing research continues to explore docetaxel-based combinations for various prostate cancer stages.