Adjuvant Radiation Therapy for T3N0 Breast Cancer Patients Older Than 75 Years After Mastectomy: A SEER Analysis.
Academic Article
Overview
abstract
INTRODUCTION: Breast cancer patients with tumors > 5 cm but without nodal disease who undergo mastectomy present a clinical challenge regarding the appropriate adjuvant treatment. Traditionally, postmastectomy radiation therapy (PMRT) was the standard of care. However, recent studies have suggested local failure rates without PMRT might be low enough to omit RT. This might be especially true in the elderly. PATIENTS AND METHODS: Women aged ≥ 75 years with a diagnosis of T3N0 breast cancer who had undergone mastectomy were identified from the Surveillance, Epidemiology, and End Results (SEER) 18 database. The study period was limited to 2006 to 2009 for more modern sampling. Multivariable proportional hazards modeling was used to examine the association of treatment and mortality, adjusting for demographic and clinicopathologic factors. RESULTS: A total of 635 patients were identified. The median follow-up period was 43 months. PMRT was given to 31.2% of the patients aged 75 to 79 years, 21.5% of those aged 80 to 84 years, and 11.7% of the patients aged ≥ 85 years (P < .001). The receipt of PMRT showed a trend toward improved overall survival on bivariable analysis (hazard ratio [HR], 0.58; P < .001) and multivariable analysis (HR, 0.78; P = .14). The 5-year overall survival was 64.2% for those who had received PMRT and 44.8% for those who had not. A nonsignificant trend was seen toward improved breast cancer-specific survival at 5 years on bivariable analysis (HR, 0.63; P = .09) but not on multivariable analysis. The interaction of age and PMRT receipt could have confounded the results. Patient age and tumor grade were significant indicators of the survival prognosis in these patients. CONCLUSION: The results of the present analysis of the SEER database suggest that PMRT might still be beneficial in women aged > 75 years with T3N0 disease but also supports continuing efforts to confirm whether it could be safe to omit. It is likely that efforts to subdivide this population using other factors (eg, comorbidity) will be important. The search for refined inclusion and exclusion criteria for adjuvant RT remains an important field of research both clinically and economically.
