Total Mastectomy or Breast Conservation Therapy? How Radiation Oncologist Accessibility Determines Treatment Choice and Quality: A SEER Data-base Analysis

Mastectomy and breast conservation therapy (BCT) are equivalent in survival for treatment of early stage breast cancer. This study evaluated the impact of radiation oncologist accessibility on choice of breast conserving surgery (BCS) versus mastectomy, and the appropriate receipt of radiotherapy after BCS. In the National Cancer Institute Survival, Epidemiology, and End Results data base, the authors selected breast cancer cases from 2004 to 2008 with the following criteria: T2N1M0 or less, lobular or ductal histology, and treatment with simple or partial mastectomy. We combined the Health Resources and Services Administration Area Resource File to define average radiation oncologist density (ROD) by county over the same time period. We evaluated tumor characteristics, demographic information, and ROD with respect to BCS rates and receipt of radiation therapy after BCS in univariable and multivariable analyses. In 118,773 cases analyzed, mastectomy was performed 33.2% of the time relative to BCS. After adjustment for demographic and tumor variables, the odds of having BCS versus mastectomy were directly associated with ROD (multiplicative change in odds for a single unit increase in ROD [95% CI]=1.02 [1.01-1.03]; p<0.001). Adjuvant radiation therapy was not administered in 28.2% of BCS cases. When adjusting for demographic and tumor variables, the odds of having BCS without adjuvant radiation were inversely associated with ROD (0.95 [0.94-0.97]; p<0.001). We observed a direct relationship between ROD and BCS rates independent of demographic and tumor variables, and an inverse trend for omission of radiotherapy after BCS. Access to radiation oncologists may represent an important factor in surgical choice and receiving appropriate BCT in early stage breast cancer.