Abstract
BACKGROUND: Among older women with early-stage breast cancer, patients with a short life expectancy (LE) are much less likely to benefit from adjuvant radiation therapy (RT). Little is known about the impact of physicians and regional factors on the use of RT across LE groups. OBJECTIVE: To determine the relative contribution of patient, physician, and regional factors on the use of RT. DESIGN: Retrospective cohort. SUBJECTS: Women aged 67-94 years diagnosed with stage I breast cancer between 1998 and 2007 receiving breast-conserving surgery. MEASURES: We evaluated patient, physician, and regional factors for their association with RT across strata of LE using a 3-level hierarchical logistic regression model. Risk-standardized treatment rates (RSTRs) for the receipt of radiation were calculated according to primary surgeon and region. RESULTS: Approximately 43.6% of the 2253 women with a short LE received RT, compared with 90.8% of the 11,027 women with a long LE. Among women with a short LE, the probability of receiving RT varied substantially across primary surgeons; RSTRs ranged from 27.7% to 67.3% (mean, 43.9%). There was less variability across geographic regions; RSTRs ranged from 42.0% to 45.2% (mean, 43.6%). Short LE patients were more likely to receive RT in areas with high radiation oncologist density (odds ratio, 1.59; 95% confidence interval, 1.07-2.36). CONCLUSIONS: Although there is a wide variation across geographic regions in the use of RT among women with breast cancer and short LE, the regional variation was substantially diminished after accounting for the operating surgeon.