Adjuvant radiation therapy is not associated with a survival benefit after R0 resection in non-metastatic adrenocortical carcinoma

The benefit of adjuvant radiation therapy (RT) in adrenocortical carcinoma (ACC) is not well characterized for those who undergo initial R0 surgical resection. Patients in the NCDB who underwent R0 resection were placed into two cohorts - those who underwent adjuvant RT and those who did not. 388 patients were identified with 51 receiving RT. No difference was observed between Kaplan-Meier survival estimates of the two cohorts (p ​= ​0.54). After adjusting for age, sex, co-morbidity index, race, receipt of chemotherapy, tumor size, grade, stage, and nodal stage, RT was not associated with improved OS. However, tumor size ≥6 ​cm (HR 1.54, [1.03-2.32], p ​= ​0.04), high tumor-grade (HR 3.46, [1.83-6.55], p ​< ​0.001), and N1-stage (HR 2.30, [1.06-4.94], p ​= ​0.03) were associated with worse OS, without benefit of RT on subgroup analysis of these factors. Treatment with adjuvant RT in patients with ACC who underwent R0 resection was not associated with an OS benefit.