Clinical and Translational Radiation Oncology (May 2024)

Factors influencing local control after MR-guided stereotactic body radiotherapy (MRgSBRT) for adrenal metastases

  • Gamze Ugurluer,
  • Famke L. Schneiders,
  • Stefanie Corradini,
  • Luca Boldrini,
  • Rupesh Kotecha,
  • Patrick Kelly,
  • Lorraine Portelance,
  • Philip Camilleri,
  • Merav A. Ben-David,
  • Spencer Poiset,
  • Sebastian N. Marschner,
  • Giulia Panza,
  • Tugce Kutuk,
  • Miguel A. Palacios,
  • Alessandra Castelluccia,
  • Teuta Zoto Mustafayev,
  • Banu Atalar,
  • Suresh Senan,
  • Enis Ozyar

Journal volume & issue
Vol. 46
p. 100756

Abstract

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Purpose: Stereotactic body radiotherapy (SBRT) is an effective treatment for adrenal gland metastases, but it is technically challenging and there are concerns about toxicity. We performed a multi-institutional pooled retrospective analysis to study clinical outcomes and toxicities after MR-guided SBRT (MRgSBRT) using for adrenal gland metastases. Methods and Materials: Clinical and dosimetric data of patients treated with MRgSBRT on a 0.35 T MR-Linac at 11 institutions between 2016 and 2022 were analyzed. Local control (LC), local progression-free survival (LPFS), distant progression-free survival (DPFS) and overall survival (OS) were estimated using Kaplan-Meier method and log-rank test. Results: A total of 255 patients (269 adrenal metastases) were included. Metastatic pattern was solitary in 25.9 % and oligometastatic in 58.0 % of patients. Median total dose was 45 Gy (range, 16–60 Gy) in a median of 5 fractions, and the median BED10 was 100 Gy (range, 37.5–132.0 Gy). Adaptation was done in 87.4 % of delivered fractions based on the individual clinicians' judgement. The 1- and 2- year LPFS rates were 94.0 % (95 % CI: 90.7–97.3 %) and 88.3 % (95 % CI: 82.4–94.2 %), respectively and only 2 patients (0.8 %) experienced grade 3 + toxicity. No local recurrences were observed after treatment to a total dose of BED10 > 100 Gy, with single fraction or fractional dose of > 10 Gy. Conclusions: This is a large retrospective multi-institutional study to evaluate the treatment outcomes and toxicities with MRgSBRT in over 250 patients, demonstrating the need for frequent adaptation in 87.4 % of delivered fractions to achieve a 1- year LPFS rate of 94 % and less than 1 % rate of grade 3 + toxicity. Outcomes analysis in 269 adrenal lesions revealed improved outcomes with delivery of a BED10 > 100 Gy, use of single fraction SBRT and with fraction doses > 10 Gy, providing benchmarks for future clinical trials.

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