Effect of practice integration between urologists and radiation oncologists on prostate cancer treatment patterns

Purpose: National attention has focused on whether urology-radiation oncology practice integration, known as integrated prostate cancer centers, contributes to the use of intensity modulated radiation therapy, a common and expensive prostate cancer treatment. Materials and Methods: We examined prostate cancer treatment patterns before and after conversion of a urology practice to an integrated prostate cancer center in July 2006. Using the SEER (Statistics, Epidemiology and End Results)-Medicare database, we identified patients 65 years old or older in 1 statewide registry diagnosed with nonmetastatic prostate cancer between 2004 and 2007. We classified patients into 3 groups, including 1 - those seen by integrated prostate cancer center physicians (exposure group), 2 - those living in the same hospital referral region who were not seen by integrated prostate cancer center physicians (hospital referral region control group) and 3 - those living elsewhere in the state (state control group). We compared changes in treatment among the 3 groups, adjusting for patient, clinical and socioeconomic factors. Results: Compared with the 8.1 ppt increase in adjusted intensity modulated radiation therapy use in the state control group, the use of this therapy increased 20.3 ppts (95% CI 13.4, 27.1) in the integrated prostate cancer center group and 19.2 ppts (95% CI 9.6, 28.9) in the hospital referral region control group. Androgen deprivation therapy, for which Medicare reimbursement decreased sharply, similarly decreased in integrated prostate cancer center and hospital referral region controls. Prostatectomy decreased significantly in the integrated prostate cancer center group. Conclusions: Coincident with the conversion of a urology group practice to an integrated prostate cancer center, we observed an increase in intensity modulated radiation therapy and a decrease in androgen deprivation therapy in patients seen by integrated prostate cancer center physicians and those seen in the surrounding health care market that were not observed in the remainder of the state.