Trends in the use of implantable accelerated partial breast irradiation therapy for early stage breast cancer in the United States.

Abstract

Background In 2002 the Food and Drug Administration approved an implantable balloon catheter that delivers accelerated partial breast irradiation (APBI) directly to the tumor bed and surrounding area after breast conserving surgery (BCS). Our aim was to determine the use of implantable APBI (IAPBI) in the United States and the patient and tumor factors associated with IAPBI use. Methods Using the Surveillance, Epidemiology, and End Results database, we conducted a retrospective analysis of patients who received whole breast radiation therapy (WBRT) or IAPBI after BCS for ductal carcinoma in situ, stage I or II breast cancer from 2000 to 2007. We determined WBRT and IAPBI rates across time and demographic and tumor factors using chi-square tests and Cochran-Armitage tests for trend for our unadjusted analyses. We used logistic regression for our multivariate analysis, allowing for adjustment for potential confounders. Results We identified 127,257 patients who met inclusion criteria. Over the study period the proportion of patients receiving IAPBI increased by 1600% (2000: 0.4%; 2007: 6.8%; p <0.001). This trend remained significant when using logistic regression (OR = 20.3, 95% CI 15.5 to 26.6). The increase in IAPBI use was statistically significant across all stage and age categories over 40 (p< 0.001). The use of IAPBI was most notable in older women (70-79 years) with a > 2100% increase in use during the study period (2000:0.4%; 2007: 9.0%; p-value <0.001). We also found significant variation in IAPBI use by region. Conclusions: IAPBI use has markedly increased since 2000, particularly in the elderly population. The rapid and widespread adoption of IAPBI is concerning, because large multicenter randomized controlled trials have not yet demonstrated long-term effectiveness of IAPBI compared to WBRT.