Intermittent docetaxel chemotherapy is feasible for castration-resistant prostate cancer.

This study was conducted with the aim to investigate the feasibility of intermittent treatment with docetaxel chemotherapy for castration-resistant prostate cancer (CRPC). A total of 51 men with CRPC received docetaxel at 75 mg/m2 every 3 weeks combined with oral dexamethasone 1.0-2.0 mg/day between 2008 and 2013. The prostate-specific antigen (PSA) level was monitored every 3 weeks. Chemotherapy was suspended when the serum PSA level decreased to < 4 ng/ml, with a reduction rate of >50% from the baseline. Treatment was resumed when serum PSA increased to > 2 ng/ml, with an increase rate of >50% from the nadir. Of the 51 cases, 27 (52.9%) qualified for intermittent treatment; 17 patients received two courses of docetaxel chemotherapy and 10 received three courses. The median off-treatment interval was 266 days for the first drug holiday, 129.5 days for the second and 146.5 days for the third. The multivariate analysis indicated low baseline PSA (<median, 30.55 ng/ml; odds ratio = 0.059, P=0.010) and low Gleason score at diagnosis (≤ 7; odds ratio = 0.016, P=0.040) as significant factors for receiving intermittent therapy. The overall survival was better in intermittent cases (hazard ratio = 2.98 by log-rank test, P=0.023). During the off-treatment period, leukopenia, thrombopenia, appetite loss, diarrhea, alopecia, nail changes and fatigue subsided (0.0-11.1%), whereas sensory and/or motor neuropathy persisted in 12 of the 27 cases (44.4%). Therefore, our intermittent regimen of docetaxel chemotherapy was found to be feasible for CRPC patients, since it may reduce adverse events without compromising the oncological outcome.