Efficacy and toxicity of q 2 weeks docetaxel versus weekly versus q 3 weeks in metastatic castration-resistant prostate cancer (CRPC).

Abstract

e16087 Background: Standard treatment for metastatic CRPC is docetaxel 75 mg/m2q3weeks. Methods: We retrospectively studied patients treated with q 1, 2, or 3 weeks docetaxel regimens at 30, 60 and 75 mg/m2, respectively. The choice of regimen and duration of treatment was decided by their oncologist. Patients who had been in a clinical trial previously, or treated with any other chemotherapy before docetaxel were excluded. On this basis 41 patients were studied. Prostate specific antigen (PSA) was used as the primary method to assess response and progression. Response was a decline of >/=50% from baseline value with no clinical or radiographic evidence of disease progression. For patients whose PSA did not decrease, progression was a >/= 25% increase from baseline. If the PSA decreased without reaching response criteria, progression was a >/= 25% increase from nadir. In those who responded, progression was a >/= 50% increase from nadir. The increase had to be at least 5ng/ml. Toxicity was graded on the basis of CTCAE version 4.0. Response rate and toxicity in the 3 arms was compared using a two by two square t-test. Results: There were 12, 14 and 15 patients in the q1w, q2w and q3w arms, respectively. Response rates, mean progression free survival (PFS), median PFS, mean overall survival (OS), median OS, mean cumulative dose (MCD) and toxicity are shown in table 1. Toxicity was similar in the q1w, q2w and q3w arms, except grade 1/2 neuropathy was higher in the q2w arm vs. the q1w arm (p=0.005). Conclusions: The MCD, response rates, PFS and OS in the q1w and q3w arms were similar to previously published reports. Patients in the q2w arm received a statistically significant higher MCD. Our data suggest a better outcome in the q2w arm as compared to the q1w and q3w arms. However, given the small number of patients studied, the results are not statistically significant. Toxicity was similar save for grade1/2 neuropathy. [Table: see text]