Omission of radiation therapy after breast-conserving surgery in the United States: A population-based analysis of clinicopathologic factors

Background: Radiation therapy (RT) after breast-conserving surgery (BCS) is associated with a significant reduction in ipsilateral breast tumor recurrence and breast cancer mortality rates in patients with early stage breast cancer. The authors of this report sought to determine which patients with breast cancer do not receive RT after BCS in the United States. Methods: The Surveillance, Epidemiology, and End Results registry was used to determine the rates of RT after BCS for women with stage I through III breast cancer in the United States from 1992 through 2007. A multivariate analysis was performed to identify independent predictors of omission of RT. Results: In total, 294,254 patients with invasive, nonmetastatic breast cancer were identified who underwent surgery from 1992 through 2007. Most patients (57%) underwent BCS; among those, 21.1% did not receive RT after BCS. The omission of RT increased significantly from 1992 (15.5%) to 2007 (25%). The receipt of RT also decreased significantly for patients with increased cancer stage, age <55 years, high-grade tumors, large tumors, positive or untested lymph node status, African American or Hispanic race, and negative or unknown estrogen receptor status. Significant geographic variation was observed in the rates of RT after BCS. Conclusions: The omission of RT after BCS was more common in recent years, especially among women who had an increased risk of breast cancer recurrence. This trend represents a serious health care concern because of the potential increased risk of local recurrence and breast cancer mortality.