Login to Access Video or Poster Abstract: MP53-06
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Introduction

There is an ongoing debate whether the effective period of androgen-deprivation therapy (ADT) or nadir prostate-specific antigen (PSA) level during non-castration-resistant prostate cancer affects the further therapeutic effect of docetaxel when patients become castration resistant. Herein, our aim was to investigate the prognostic value of response duration of ADT in castration-resistant prostate cancer (CRPC) treated with docetaxel chemotherapy.

Methods

We retrospectively reviewed the medical records of 201 patients who received ADT therapy before docetaxel treatment. Docetaxel at a dose of 75 mg/m² was administered every 3 or 4 weeks. We defined the effective period of first ADT based upon prostate cancer clinical trials working group 3 (PCWG-3) criteria. Patient clinico-pathological data were collected to assess the prognostic factors for cancer-specific survival (CSS).

Results

Among the 201 patients, median age was 73 years and the median follow-up period was 45.5 months. Bone metastases were found in 134 (66.7%) patients, and 85 (42.3%) patients had an EOD grade of 2 or higher. Visceral metastases were found in 47 patients (23.4%). Median CSS and progression-free survival were 21.5 months and 13.5 months, respectively. The median response duration of ADT was 29.2 months. Overall, 121 (60.2%) patients achieved PSA nadir <0.2 ng/ml during first ADT. According to the Kaplan–Meier method, the 2-year CSS rate for first ADT ≥16 months was 62.9%, whereas the counterpart was 32.1% (p<0.001). Furthermore, the 2-year survival rate for nadir PSA <0.2 ng/ml was 65.4%, whereas the counterpart was 40.2% (p=0.002). Multivariate analysis indicated that first ADT response <16 months, pretreatment PSA level ≥20 ng/ml, visceral metastasis, and ALP ≥284 were independent prognostic factors for CSS (HR=2.28, HR=1.69, HR=2.65, and HR=1.98, respectively). However, the degree of nadir PSA level during ADT did not have a significant association with CSS.

Conclusions

Our results clearly suggested that the effective duration of first ADT was a significant biomarker for predicting the treatment response for CRPC treated with first-line docetaxel.

Funding

none_x000D_