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

BACKGROUND: In 2002, the US Food and Drug Administration approved an implantable balloon catheter that delivers accelerated partial breast irradiation (APBI) after breast-conserving surgery (BCS). The objective of the current study was to determine the use of implantable APBI (IAPBI) in the United States and factors associated with IAPBI use. METHODS: By using the Surveillance, Epidemiology, and End Results database, the authors conducted a retrospective analysis of patients who received whole-breast radiotherapy (WBRT) or IAPBI after BCS for ductal carcinoma in situ, AJCC stage I, or stage II breast cancer from 2000 to 2007. WBRT and IAPBI rates were determined across time and demographic and tumor factors using chi-square tests and Cochran-Armitage tests for trend for the unadjusted analyses. RESULTS: A total of 127,257 patients who met inclusion criteria were identified. Over the study period, the proportion of patients receiving IAPBI increased by 1600% (from 0.4% in 2000 to 6.8% in 2007; P <.001). This trend remained significant when using logistic regression (odds ratio, 20.3; 95% confidence interval, 15.5-26.6). The increase in IAPBI use was statistically significant across all stage and age categories >40 years (P <.001). The use of IAPBI was most notable in older women (ages 70-79 years), with a >2100% increase in use noted during the study period (0.4% in 2000 vs 9.0% in 2007; P <.001). The authors 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 the long-term effectiveness of IAPBI compared with WBRT.