Determinants of the Combined Use of External Beam Radiotherapy and Brachytherapy for Low-Risk, Clinically Localized Prostate Cancer

BACKGROUNDProstate cancer treatment choices have been shown to vary by physician and patient characteristics. For patients with low-risk, clinically localized prostate cancer, the authors examined the impact of their clinical, sociodemographic, and radiation oncologists' (RO) characteristics on the likelihood that the patients would receive combined external beam radiotherapy and brachytherapy, a treatment regimen that is at variance with clinical guidelines. METHODSThe Surveillance, Epidemiology and End Results (SEER)-Medicare linked database and the American Medical Association Physician Masterfile were used in a retrospective analysis of 5531 patients with low-risk, clinically localized prostate cancer who were diagnosed between 2004 and 2007, and the 708 ROs who treated them. Hierarchical logistic regression analyses were used to evaluate the relationship between patient and RO characteristics and the use of combined therapy within 6 months of diagnosis. RESULTSOverall, 356 patients (6.4%) received combined therapy. Nonclinical factors were found to be associated with combined therapy. After adjusting for patient and RO characteristics, the odds of receiving combined therapy for patients residing in Georgia were found to be significantly greater than for all other SEER regions. Black patients were significantly less likely to receive combined therapy (odds ratio, 0.62; 95% confidence interval, 0.40-0.96 [P=.03]) compared with white patients. In addition, ROs accounted for 36.6% of the variation in patients receiving combined therapy. CONCLUSIONSGeographic and sociodemographic factors were found to be significantly associated with guideline-discordant combined therapy for patients diagnosed with low-risk, clinically localized prostate cancer. Which RO a patient consults is important in determining whether they receive combined therapy. Cancer 2013;119:3619-3628. (c) 2013 American Cancer Society.