Docetaxel-related toxicity in metastatic hormone-sensitive and metastatic castration-resistant prostate cancer

Michael T. Schweizer, Roman Gulati, Elahe A. Mostaghel, Peter S. Nelson, R. Bruce Montgomery, Evan Y. Yu, Heather H. Cheng

Docetaxel plus androgen deprivation therapy (ADT) offers a survival benefit in metastatic hormone-sensitive prostate cancer (mHSPC). However, one trial evaluating docetaxel in mHSPC (GETUG-AFU15) showed unexpected toxicity; raising concerns that docetaxel may carry increased toxicity when used to treat mHSPC compared to metastatic castration-resistant prostate cancer (mCRPC). We conducted a retrospective analysis evaluating differences in toxicity based on the clinical state (i.e., mHSPC vs. mCRPC) that docetaxel was used. Patients initiating docetaxel between 1/1/2014 and 7/15/2015 were included, with the former date chosen to coincide with the press release for the first mHSPC study that showed a survival benefit with early docetaxel; ensuring contemporary docetaxel-treated cohorts. Thirty-nine mCRPC and 22 mHSPC patients were included. Compared to mCRPC, mHSPC patients were younger (median years: 66.3 vs. 71.8, P = 0.007); had better performance status (ECOG 0-1: 100 vs. 62 %, P < 0.0001); and used opiates less frequently (29 vs. 66 %, P = 0.04). Neutropenic fevers occurred in 9 and 5 % (P = 0.95) of men with mHSPC and mCRPC, respectively. Other toxicities also occurred at similar rates between cohorts. The incidence of any toxic event was 73 and 67 % (P = 0.84) for men with mHSPC and mCRPC, respectively. Within the mHSPC cohort, neutropenic fevers occurred at a similar rate regardless of the time interval between initiating ADT and the start of docetaxel. We did not observe a significant difference in toxicity between mHSPC and mCRPC patients receiving docetaxel. However, the small sample size and retrospective nature of this study limit our ability to draw definitive conclusions.