Predictive Factor for the Early Progression of Androgen Independent Prostate Cancer in Intermittent Androgen Deprivation Therapy

Shin, Jae Sung; Choi, Hyung Joon; Choi, Yang Soo; Chai, Soo Eung; Choi, Han Yong

Abstract

PURPOSE: The purpose of this study was to define the predictive factors for the early progression of androgen independent prostate cancer in patients receiving intermittent androgen deprivation (IAD) therapy.
MATERIALS AND METHODS
A total of 101 patients (stages A to C in 29 and stage D in 72), who had completed at least 1 cycle of IAD, were included. A variety of possible prognostic factors, such as age, initial prostate-specific antigen (PSA) and testosterone, Gleason score, lymph node or bone metastasis, nadir PSA and testosterone, duration to nadir PSA, duration of off treatment, and ECOG performance index were analyzed using uni- and multivariate tests.
RESULTS
Patients had completed at least one, and up to six, treatment cycles with a median follow-up of 43 (13-100) months. The median nadir PSA levels were 0.28, 0.41, 0.71, 0.88, 1.85 and 0.79ng/ml for cycles 1 to 6 (median 4.6 months), respectively. The median one cycle duration (on off treatment) was 14 months, 44% of that time spent off treatment, but the off treatment duration decreased with increasing number of treatment cycles. A total of 42 patients progressed to androgen independent prostate cancer, and the progression free rates at 36 and 60 months were 72 and 52%, respectively, according to the Kaplan-Meier method. Using multivariate analysis, the nadir PSA (p=0.044), ECOG performance index (p= 0.039) and lymph node or bone metastasis (p=0.03) were the strongest predictors for the progression of androgen independent prostate cancer.
CONCLUSIONS
On receiving IAD, prostate cancer patients with lymph node or bone metastasis, a poor performance status and comparatively higher serum PSA nadir value after the first treatment phase, there is a high possibility for the early progression of androgen independent prostate cancer.