Objective: The objective of this study was to evaluate a single institution's experience with stereotactic body radiotherapy (SBRT) in treating malignant adrenal lesions, as well as the prognostic value of systemic inflammation biomarkers.
Materials and methods: From November 2007 to February 2018, 27 patients with malignant adrenal lesions received 31 SBRT treatments. Outcomes, measured from the date of SBRT, included overall survival (OS), local control (LC), and freedom from progression. Cox proportional hazard model was utilized to identify potential prognostic factors. Tumor response was assessed with PET Response Evaluation Criteria In Solid Tumors (PERCIST)/Response Evaluation Criteria in Solid Tumors (RECIST) criteria. Acute toxicity was evaluated with the National Cancer Institute Common Terminology Criteria for Adverse Events, version 4.03 criteria.
Results: Median follow-up for all patients was 8 months. The complete response, partial response, stable disease, and progressive disease rates were 59%, 9%, 32%, and 0%, respectively. One-year LC, OS, and freedom from progression were 77.7%, 38.0%, and 10.0%, respectively. There was a trend toward significance upon multivariate analysis for pretreatment neutrophil to lymphocyte ratio >4.1 to predict inferior OS (adjusted hazard ratio=3.29, P=0.09, 1-year OS: 11% vs. 80%). There were 3 cases (10%) complicated by grade 2 acute toxicity, including nausea and fatigue. There was 1 grade 5 toxicity, as 1 case was complicated by a fatal gastric ulcer occurring 3 months after SBRT to the left adrenal gland (112.5 BED10).
Conclusions: These results support the limited existing literature, demonstrating that SBRT provides adequate LC for adrenal lesions with minimal toxicity. Pretreatment neutrophil to lymphocyte ratio may serve as a prognostic factor in these patients.