Clinical Impact of the Number of Treatment Cycles in First-Line Docetaxel for Patients With Metastatic Castration-Resistant Prostate Cancer
In this retrospective study we compared survival outcome in a cohort of patients treated with 6 to 8 versus ≥ 9 cycles of docetaxel, administered as first-line chemotherapy in metastatic castration-resistant prostate cancer. Treatment with ≥ 9 cycles of docetaxel was found to be an independent predictor of overall survival suggesting that a higher number of treatment cycles might be beneficial in this group of patients.Background:
We investigated the impact of the number of docetaxel cycles administered in patients with metastatic castration-resistant prostate cancer (mCRPC) treated with first-line chemotherapy.Patients and Methods:
Charts from 421 consecutive patients who initiated standard treatment with docetaxel-based chemotherapy (75 mg/m2 every 3 weeks) between 2007 and 2013 were reviewed. Patients who received < 6 cycles of docetaxel were excluded from the analysis. Remaining patients were divided into 2 groups on the basis of whether or not ≥ 9 cycles of docetaxel were administered (n = 108 and 184, respectively). Reasons for treatment discontinuation and postdocetaxel treatments were registered. Prostate-specific antigen (PSA) responses were defined as a confirmed ≥ 50% decrease in baseline PSA levels. Overall survival (OS) was calculated from start of therapy using the Kaplan–Meier method. Cox proportional hazards were calculated to estimate the effect of clinical variables on OS.Results:
OS was longer in patients treated with ≥ 9 cycles of docetaxel (21.9 months vs. 17.2 months; P < .0001, log rank). Survival also favored patients treated with ≥ 9 cycles of docetaxel when only patients ending docetaxel because of toxicity or treatment conclusion (22.3 vs. 19.4 months; P = .048, log rank) or patients who achieved a PSA response (22.3 vs. 18.7 months; P = .012, log rank) were evaluated. mCRPC-related prognostic factors and patients who received ≥ 1 subsequent line of therapy post-docetaxel were well balanced.Conclusion:
On the basis of our retrospective findings, a superior OS was found in patients treated with ≥ 9 cycles of docetaxel when adjusting for known prognostic factors. Dose reductions might increase the number of docetaxel cycles administered.