The use of supplemental external beam radiotherapy in men with low-risk prostate cancer undergoing brachytherapy before and after the 1999 American Brachytherapy Society Guideline statement

PURPOSE: In 1999, the American Brachytherapy Society (ABS) recommended brachy-monotherapy for men with low-risk prostate cancer because of the potential for increased toxicity with combined external beam radiotherapy (EBRT) and brachytherapy without the proof of increased efficacy. We investigated the patterns of care in the community in this patient population before and after the reporting of the ABS guideline. METHODS AND MATERIALS: The study cohort consisted of 4943 men (median age, 69.0 years) with low-risk prostate cancer treated with brachytherapy with or without supplemental EBRT from 1991 to 2007 across 21 community radiation oncology centers. Multivariable logistic regression analysis was performed to determine if there was a significant association between the year of brachytherapy, prostate-specific antigen level, clinical tumor (T) category, patient's age, and the use of supplemental EBRT. RESULTS: Supplemental EBRT was used in 647 men (13%). The EBRT use initially increased until 2001 and then decreased yielding a significant association (adjusted odds ratio [AOR], 0.92; p <0.001) between the EBRT use and the year of brachytherapy using a quadratic formulation. Specifically, EBRT use peaked at 24.6% in 2001 and subsequently declined to 3.3% by 2007. Men with clinical category T2a as compared with Tic disease (AOR, 1.43; p <0.001) were more likely to receive combined modality therapy. CONCLUSIONS: The use of supplemental EBRT in men with low-risk prostate cancer treated with brachytherapy has decreased since 2001. This change in practice patterns suggests gradual adoption of the 1999 ABS practice guidelines. (C) 2010 Published by Elsevier Inc. on behalf of American Brachytherapy Society.