Stereotactic Body Radiotherapy for Adrenal Gland Metastases: Single-Center Experience

Abstract

OBJECTIVEIn this study, we aimed to analyze the results of stereotactic body radiotherapy (SBRT) in patients withadrenal gland metastasis due to different primary tumors.METHODS26 patients with 29 adrenal gland metastases who were treated between 2011-2018 with CyberknifeRobotic System were evaluated retrospectively.RESULTSThe origin of adrenal gland metastasis was lung in 22 patients, breast in 1 patient, parotid gland in 1patient, and sarcoma in 2 patients. Fifteen patients (58 %) had other organ metastasis in addition to theadrenal metastases. Six patients were treated for synchronous metastasis and 20 patients for metachronous metastasis. SBRT was performed in median 3 fractions (3–5 fractions), and the median prescription dose to PTV was 30 Gy (18- 45 Gy), with a BED10 (Biological Equivalent Dose) value of 60 Gy(28.8-112,5 Gy). The median follow-up time was 11 months (1-34 months), and median overall survivalwas 12 months after SBRT, 1,2-years survival rates were 49,7%, 21% respectively. Median time to localfailure was not reached, and the 6-months, 1 and 2-years local failure free survival rates were 78,6%,66,5% and 66,5% respectively. The presence of metastatic disease outside the adrenal gland was foundto be a significant prognostic factor on survival after SBRT in both univariate and multivariate analyzes,(HR:3; 95% CI 1,06-8,55 p:0,04). In general treatment was well tolerated and no major acute toxicitieswere observed.CONCLUSIONSBRT provides high local control rates and a well tolerated treatment in patients with adrenal glandmetastases. Survival is particularly encouraging for patients with solitary adrenal metastasis.