Real-World Treatment Patterns in Men with Castration- Resistant Prostate Cancer Receiving Docetaxel

Background: Docetaxel has been a standard of care for castration-resistant prostate cancer (CRPC) in the United States since 2004, yet little has been reported on its patterns of use in routine practice. To help understand these patterns, a retrospective study was conducted and is reported here. Methods: Medical records from 394 patients treated in the United States were reviewed. Data were collected by 48 physicians from oncology (patient N=344) and 8 physicians from urology (patient N=50) practices. Inclusion criteria were: CRPC diagnosed between 2004 and 2010; received docetaxel; discontinued docetaxel due to rising prostate-specific antigen (PSA), progression of bone lesions, or progression of nodal or visceral metastases. Data were collected from physicians using an internet-based case report form. We evaluated patient demographics, characteristics of the docetaxel regimen, and other treatments used until docetaxel discontinuation. Results: Patients had a mean [±SD] age of 66.5 [8.9] years, the majority (63%) were white, and geographic dispersion was similar to the US population. The majority of patients initiated docetaxel between 2008 and 2010. After CRPC diagnosis, 8% of patients had initiated another cancer-directed therapy before starting docetaxel. Most (78.9%) patients initiated docetaxel with prednisone, while 18.5% initiated docetaxel alone and 2.6% initiated with other medications. Half of patients initiated docetaxel within 1 month after CRPC diagnosis, while 25% started ≥6 months later. Other non-chemotherapy treatments used with docetaxel were hormonal therapy (22.8%), radiotherapy (17.3%), and surgery (4.1%). Most patients (75%) received ≥4 docetaxel cycles, half received ≥6 cycles, 25% received ≥8 cycles and 10% received ≥10 cycles. Increased tumor mass, with/without new bone lesions or rising PSA, was the most common reason for docetaxel discontinuation (74% of patients). Conclusions: Concordant with guidelines, docetaxel and prednisone was the preferred first-line chemotherapy regimen in CRPC patients reviewed for this study. However, one quarter of patients did not initiate docetaxel until ≥6 months after CRPC diagnosis and total exposure varied considerably, with only 10% receiving ≥10 cycles. Future studies are needed to describe specific reasons explaining timing of docetaxel initiation and duration of exposure in some CRPC patients.