Differences in treatment patterns among patients with castration-resistant prostate cancer treated by oncologists versus urologists in a US managed care population

OBJECTIVE: Differences in treatment patterns, health care resource utilization, and costs between patients with castration-resistant prostate cancer (CRPC) treated by oncologists and those treated by urologists were examined. METHODS: Patients aged ≥40 with CRPC were identified using claims from a large US managed health care plan between July 2001 and December 2007. A 6-month baseline period was used to assess patient characteristics. Patients with visits to an urologist, without visits to an oncologist, were assigned to the urology cohort, and patients with visits to an oncologist, with or without visits to an urologist, were assigned to the oncology cohort. Treatment patterns, health care resource utilization, and costs during a variable follow-up period were compared between cohorts using descriptive statistics and Lin’s regression. RESULTS: The urology cohort had fewer comorbid illnesses (P < 0.001) and patients were less likely to have other cancers during baseline (P < 0.001) or to die during follow-up (P = 0.004) compared with the oncology cohort. The oncology cohort patients were significantly more likely to have a claim for hormones (74.5% vs 61.1%; P < 0.001), chemotherapy (46.9% vs 10.2%, P < 0.001), and radiation (22.3% vs 3.7%, P < 0.0001) over follow-up. Mean unadjusted health care costs were higher in the oncology vs the urology cohort (US$31,896 vs US$15,318, respectively; P < 0.001). At 6 years follow-up, cumulative adjusted CRPC-specific costs were significantly higher among patients treated by oncologists with chemotherapy than among patients treated by urologists. CONCLUSION: CRPC patients treated by oncologists had greater use of hormones, chemotherapy, and radiation; higher percentages of patients with inpatient stays, emergency room, and ambulatory visits; and higher health care costs, than patients treated by urologists.