OBJECTIVES: Docetaxel (D) is well recognized as the first-line chemotherapy in patients with metastatic prostate cancer (PC). Of interest is the relationship between the number of treatment cycles and overall survival (OS) benefit. This study investigated the relationship between number of cycles and OS in a community practice. METHODS: The Georgia Cancer Specialist Database (2003-2008) was used. Patients with initial stage IV PC receiving D were followed from the date of first D use to the earlier of death or loss to follow-up. The three-month period prior to the first D use was the baseline. Patients were stratified into <10 vs. ≥10 groups based on mean cycle number. OS was compared using the Kaplan-Meier curve.  The impact of cycle number on OS was further examined using multivariate Cox model with adjustment of age, comorbidity, baseline PSA, baseline bisphosphonate use, hormonal therapies and other chemotherapy during the follow-up. Sensitivity analyses (SA) with cycle number controlled as a count variable and a dummy variable (with different thresholds at 6, 7, 8, 9) were performed to test the robustness of the association. RESULTS: The sample included 47 patients, with mean age 75 (ranging 58-95), average baseline PSA 296 ng/ml (ranging 0.21-2139). The average number of treatment cycles were 10 (ranging 1-52), with 27 (57.5%) completing <10 and 19 (42.5%) patients ≥10 cycles. Median survival was 224 days for <10 group, and 570 days for ≥10 group (P=0.0011). The Cox model found a higher likelihood of survival for ≥10 group (HR=0.33, P=0.0117).  Consistent results were found in SA. CONCLUSIONS: This study suggested that more treatment cycles of D was associated with prolonged OS for metastatic PC. The results could be confounded by unadjusted factors, therefore, no cause inference can be drawn based on this analysis.