Background: Docetaxel has been a standard of care for castration-resistant prostate cancer (CRPC) in the US since 2004 (TAX 327), 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 US were reviewed: 48 from oncology (N=344) and 8 from urology (N=50) practices. Inclusion criteria were: CRPC diagnosed between 2004 and 2010; received docetaxel; discontinued docetaxel due to rising 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 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 drugs. 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. However, one quarter of patients did not initiate docetaxel until ≥ 6 months after CRPC diagnosis and total exposure varied considerably, with only 10% receiving geater than or equal to 10 cycles. Future studies are needed to describe specific reasons for docetaxel delay and sub-maximal exposure in some CRPC patients.
