Presenter: Daniel Nelson DO

Background: Adrenocortical carcinoma (ACC) is a rare and aggressive malignancy for which surgery is the mainstay of treatment and adjuvant radiation is infrequently employed. However, small, single-institution series suggest that adjuvant radiation may improve survival for some ACC patients.

Methods: All patients with non-metastatic ACC treated with either surgical resection alone or surgical resection followed by adjuvant radiation were identified in the 2004-2013 National Cancer Database. Patients with tumors <1cm were excluded to eliminate incidental ACC as well as patients that died within 30 days of surgery. This study determined factors associated with receipt of radiation and the impact of adjuvant radiation on survival.

Results: Of 1,197 patients, 173 (14%) received adjuvant radiation. Patient demographics were similar between the two groups, but those receiving radiation were more likely to have had positive margins following surgery (37 vs 15%; p<0.001) as well as receive concurrent chemotherapy (57 vs 29%; p<0.001). After adjustment for tumor and other treatment factors, only positive margins following surgery was associated with an increased likelihood of receiving adjuvant radiation (OR 3.13; CI 1.64-5.98; p<0.001). Radiation therapy did not confer a difference in median 1, 3, or 5-year overall survival (p=NS) in the general cohort, whereas higher grade histology (HR 4.61; CI 1.55-13.7, p=0.01), positive margins (HR 1.74; CI 1.02-2.96, p=0.04), and vascular invasion (HR 1.77; CI 1.11-2.84, p=0.02) independently decreased survival. However, for patients with positive margins following surgery, adjuvant radiation was associated with a 35% decreased yearly risk of death (HR 0.65; CI 0.43-0.97; p=0.03). This survival advantage was not evident for patients with other traditional high risk features such as age >55, positive lymph nodes or high grade histology.

Conclusion: Adjuvant radiation appears to decrease the risk of death in ACC patients with positive margins following surgical resection, but only a small percentage are currently receiving radiation. Multidisciplinary treatment with surgery and radiation should be strongly considered for these patients.