Adjuvant Radiation is Associated with Improved Survival for Select Patients with Non-metastatic Adrenocortical Carcinoma

Adrenocortical carcinoma (ACC) is a rare and aggressive malignancy for which surgery is the mainstay of treatment and for which adjuvant radiation is infrequently employed; however, small, single-institution series suggest adjuvant radiation may improve outcomes.

All patients with non-metastatic ACC treated with either surgery alone or surgery followed by adjuvant radiation were identified in the 2004–2013 National Cancer Database. Factors associated with receipt of radiation and the impact of adjuvant radiation on survival were determined by multivariable analysis.

Of 1184 patients, 171 (14.4%) 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 (37.4 vs. 14.6%; p < 0.001), evidence of vascular invasion (14.0 vs. 5.1%; p = 0.05), and receive concurrent chemotherapy (57.3 vs. 28.8%; 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 (odds ratio 3.84, 95% confidence interval [CI] 1.95–7.56). Radiation therapy did not confer a difference in median overall survival in the general cohort. However, for patients with positive margins, adjuvant radiation was associated with a 40% decreased yearly risk of death after adjustment for concurrent chemotherapy (hazard ratio 0.60, 95% CI 0.40–0.92; p = 0.02). This survival advantage was not evident for other traditional high-risk features.

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 considered for these patients.