title: Urologists' use of intensity-modulated radiation therapy for prostate cancer.
abstract: BACKGROUND
  Some urology groups have integrated intensity-modulated radiation therapy (IMRT), a radiation treatment with a high reimbursement rate, into their practice. This is permitted by the exception for in-office ancillary services in the federal prohibition against self-referral. I examined the association between ownership of IMRT services and use of IMRT to treat prostate cancer.
  
  
  METHODS
  Using Medicare claims from 2005 through 2010, I constructed two samples: one comprising 35 self-referring urology groups in private practice and a matched control group comprising 35 non-self-referring urology groups in private practice, and the other comprising non-self-referring urologists employed at 11 National Comprehensive Cancer Network centers matched with 11 self-referring urology groups in private practice. I compared the use of IMRT in the periods before and during ownership and used a difference-in-differences analysis to evaluate changes in IMRT use according to self-referral status.
  
  
  RESULTS
  The rate of IMRT use by self-referring urologists in private practice increased from 13.1 to 32.3%, an increase of 19.2 percentage points (P<0.001). Among non-self-referring urologists, the rate of IMRT use increased from 14.3 to 15.6%, an increase of 1.3 percentage points (P=0.05). The unadjusted difference-in-differences effect was 17.9 percentage points (P<0.001). The regression-adjusted increase in IMRT use associated with self-referral was 16.4 percentage points (P<0.001). The rate of IMRT use by urologists working at National Comprehensive Cancer Network centers remained stable at 8.0% but increased by 33.0 percentage points among the 11 matched self-referring urology groups. The regression-adjusted difference-in-differences effect was 29.3 percentage points (P<0.001).
  
  
  CONCLUSIONS
  Urologists who acquired ownership of IMRT services increased their use of IMRT substantially more than urologists who did not own such services. Allowing urologists to self-refer for IMRT may contribute to increased use of this expensive therapy. (Funded by the American Society for Radiation Oncology.).
authors.affiliation: From Georgetown University, Washington, DC.
authors.forename: Jean M
authors.initials: JM
authors.lastname: Mitchell
mesh_terms: D000726:Androgen Antagonists / Q000627:therapeutic use; D001918:Brachytherapy / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D006278:Medicare; D010067:Ownership; D018584:Physician Self-Referral / Q000706:statistics & numerical data*; D011471:Prostatic Neoplasms / Q000188:drug therapy / Q000532:radiotherapy*; D050397:Radiotherapy, Intensity-Modulated / Q000191:economics / Q000706:statistics & numerical data*; D012017:Referral and Consultation / Q000706:statistics & numerical data; D061665:Time-to-Treatment; D014481:United States; D014572:Urology / Q000706:statistics & numerical data*
chemical_list: D000726:Androgen Antagonists