Long-term outcome of patients treated with docetaxel for hormone-dependent prostate-specific antigen (PSA) progression after local therapy for prostate cancer

Abstract

16030 Background: Mechanisms of chemotherapy resistance increase as cancer progresses, and a treatment approach that targets prostate tumors early, before hormonal therapy, may result in an improved outcome. A long-term outcomes analysis of our prior published study (treating patients for up to 8 months of docetaxel) was conducted to determine if the natural history of patients with PSA progression was altered by docetaxel. Methods: Twenty patients treated on our prior study were assessed for long-term follow up at a median of 9.4 years. All patients were followed until PSA progression (increase of 2 ng/mL over nadir) without the introduction of androgen ablation therapy, but may have received androgen ablation prior to radiographic progression (i.e., metastatic disease). One patient was excluded from the current analysis due to stage D1 disease pre-trial. Time to PSA progression, time to radiographic progression, and mortality were assessed. Comparisons were made between responders and non-responders to docetaxel (responders = PSA decrease ≥ 50%). Kaplan-Meier curves were constructed for the time to radiographic progression and mortality data. Results: Nineteen patients were treated on the original study with a mean time to PSA progression after local therapy of 3.3 years and a mean pre-trial PSA doubling time of 186 days. On docetaxel therapy, 8 (42%) of 19 patients demonstrated a decrease in PSA by ≥ 50% for at least 4 weeks. The median time to PSA progression after trial end was 57.5 vs. 20.0 days among PSA responders and non-responders respectively. The median time to radiographic progression from diagnosis of prostate cancer was 56.5 (95% CI: 27.7 to 99.8) vs. 45.3 months (95% CI: 40.3 to 82.5) among PSA responders and non-responders respectively. There were 4 deaths in the follow up period. Conclusions: Although treatment with docetaxel did not appear to alter overall progression in this small study, the trend towards longer time to disease progression in PSA responders suggests activity, and warrants larger studies of chemotherapy in this patient population. No significant financial relationships to disclose.