Trends in the use of breast-conserving surgery and adjuvant radiation therapy in patients with DCIS: A U.S. population-based analysis from 1996 to 2007.

Abstract

1031 Background: The treatment for patients with DCIS remains controversial. Current guidelines based upon best available evidence suggest that breast conserving surgery (BCS) followed by adjuvant radiation therapy (RT) result in acceptable local control and breast cancer specific survival. The purpose of this study was to analyze trends in patterns of care as well as identify factors associated with surgery type and use of adjuvant radiation therapy in a select cohort of patients enrolled into the SEER database. Methods: The study included females 18 years and older with focal DCIS and known tumor size of 5 cm or less diagnosed between 1996 and 2007. The Cochran-Armitage trend test was applied to identify trends in the use of BCS and RT over time. Multivariate logistic regression analyses were used to determine factors associated with receiving BCS vs. mastectomy and BCS plus RT vs. BCS alone. Cox proportional hazard model was used to determine associations with breast cancer-specific mortality. Results: Of the 34,233 women with DCIS, 76.59% were treated with BCS. 66.36% of BCS patients received adjuvant RT over the study period. The proportion of women receiving BCS increased from 71.5% in 1996 to 76.9% in 2007 (p<0.0001). Additionally, the proportion of women who underwent BCS and received adjuvant radiation therapy over the same time period increased from 55.3% to 69.7% (p<0.0001). Multivariate analysis demonstrated that year of diagnosis, race, marital status, geographic region, tumor size, tumor grade and comedo necrosis all were significantly associated with the use of adjuvant radiation therapy, but age was not. Cox proportional hazards models did not associate either surgery type or use of adjuvant radiation in patients undergoing BCS with breast cancer-specific mortality. Conclusions: Based upon reporting within the SEER database, the proportion of DCIS patients undergoing BCS and the BCS patients receiving adjuvant radiation increased over the study time period. Surgery type and use of adjuvant radiation therapy in patients with BCS was not associated with decreased risk of breast-cancer specific death in this cohort.