Short-term complications and use of breast brachytherapy in the national Medicare population in 2008-2009.

Abstract

1030 Background: Brachytherapy as an alternative to whole-breast irradiation (WBI) for early-stage breast cancer has disseminated into clinical practice; however, current national treatment patterns and associated complications remain unknown. Methods: We constructed a national sample of Medicare beneficiares aged 66 to 94 who underwent breast conserving surgery in 2008-2009 and who were treated with brachytherapy or WBI. We used hospital referral regions to assess national treatment variation and an instrumental variable analysis to compare complication rates between treatment groups, adjusting for patient and clinical characteristics such as age, number of comorbidities, receipt of chemotherapy or screening mammogram, and type of radiation facility. We compared one-year overall, wound and skin, and deep tissue and bone complications between brachytherapy and WBI using specific procedure and diagnosis codes identified in Medicare claims. Results: Of the 29,648 women in our sample, 4,671 (15.8%) received brachytherapy. The median percent of patients receiving brachytherapy varied substantially across hospital referral regions (interquartile range: 7.5%-23.3%). In the bivariate analysis, 34.3% of women treated with brachytherapy had a complication compared to 27.3% of those who received WBI (P<0.001). After adjusting for patient and clinical characteristics, 35.3% (95% CI: 34.7, 35.8) of women treated with brachytherapy had a complication compared to 18.7% (95% CI: 18.2,19.2) treated with WBI (average predicted difference: 16.5%, 95% CI: 15.8, 17.3, P<0.001). While brachytherapy was associated with a 16.9% (95% CI: 10.0, 23.8, P<0.001) higher absolute percentage of wound and skin complications compared to WBI, there was no difference in deep tissue and bone complications. Conclusions: Brachytherapy is commonly used among Medicare beneficiaries; in some regions nearly one in four women who underwent adjuvant radiation received brachytherapy. After one year, wound and skin complications were significantly more common among women who received brachytherapy compared to those receiving WBI, but there was no difference in deep tissue and bone complications.