Multi-institutional review of SBRT for adrenal metastasis: Turkish Radiation Oncology Society Study
PO-1440
Abstract
Multi-institutional review of SBRT for adrenal metastasis: Turkish Radiation Oncology Society Study
Authors: Aysenur Elmali1, Berna Akkus Yildirim2, Mustafa Cengiz1, Sezin Yuce Sari1, H. Cem Onal2, Tanju Berber3, Aysun Arslantas Erken3, Teuta Zoto Mustafayev4, Banu Atalar4, Ilhami Unal5, Nuri Kaydihan6, Fazilet Oner Dincbas6
1Hacettepe University, Radiation Oncology, Ankara, Turkey; 2Baskent University, Radiation Oncology, Adana, Turkey; 3Prof. Dr. Cemil Tascioglu City Hospital, Radiation Oncology, Istanbul, Turkey; 4Acıbadem Maslak Hospital, Radiation Oncology, Istanbul, Turkey; 5Guven Hospital, Radiation Oncology, Ankara, Turkey; 6Memorial Bahcelievler Hospital, Radiation Oncology, Istanbul, Turkey
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Purpose or Objective
The current literature on adrenal stereotactic body radiotherapy (SBRT) is still limited. The purpose of this study is to report the outcomes of SBRT for adrenal metastasis in a retrospective multi-institutional cohort.
Material and Methods
The outcome of 124 patients with 146 adrenal metastases who underwent SBRT within 11 years (2008-2019) was evaluated. Survival outcomes were analyzed by the Kaplan-Meier method. Patient, tumor, and treatment characteristics and their effects on survival, local control, and toxicity outcomes were analyzed by Log-rank and multivariate Cox regression methods.
Results
The median age at treatment was 60 years. The most frequent primary tumor site was the lung followed by the gastrointestinal system and the breast. The adrenal gland was the only metastatic site in 49 patients (42%). The most common fractionation schedule was 30 Gy in 5 fractions. Median BED10 was 61 Gy. After a median follow-up of eight months, 24 local failures were observed, and the one- and two-year local recurrence-free survival rate was 79% and 69%, respectively. The median overall survival (OS) was 35 months, and the one- and two-year OS rate was 83% and 60%, respectively. The overall local control (LC) rate was 83% and it was positively correlated with the BED10 and fraction dose. An improved OS was observed in cases with non-lung cancer, <4 cm lesion, and isolated adrenal metastasis (Fig 1.) although the latter not statistically significant. Fourteen patients reported an acute toxicity and late toxicity was observed in three patients.
Conclusion
A satisfactory LC rate was achieved for adrenal metastasis via SBRT with minimal toxicity. A higher BED10 and fraction dose are positive prognostic factors for tumor control.