Low-Energy X-Ray Intraoperative Radiation Therapy (Lex-IORT) for Resected Brain Metastases: A Single-Institution
Christian D Diehl1,2,3, Steffi U Pigorsch1,2,3, Jens Gempt4
1Department of Radiation Oncology, School of Medicine, Klinikum Rechts der Isar, Technical University of Munich (TUM), 81675 Munich, Germany.
Background:
Resection followed by local radiation therapy (RT) is the standard of care for symptomatic brain metastases. However, the optimal technique, fractionation scheme and dose are still being debated. Lately, low-energy X-ray intraoperative RT (lex-IORT) has been of increasing interest.
Method:
Eighteen consecutive patients undergoing BM resection followed by immediate lex-IORT with 16-30 Gy applied to the spherical applicator were retrospectively analyzed. Demographic, RT-specific, radiographic and clinical data were reviewed to evaluate the effectiveness and safety of IORT for BM. Descriptive statistics and Kaplan-Meyer analysis were applied.
Results:
The mean follow-up time was 10.8 months (range, 0-39 months). The estimated local control (LC), distant brain control (DBC) and overall survival (OS) at 12 months post IORT were 92.9% (95%-CI 79.3-100%), 71.4% (95%-CI 50.2-92.6%) and 58.0% (95%-CI 34.1-81.9%), respectively. Two patients developed radiation necrosis (11.1%) and wound infection (CTCAE grade III); both had additional adjuvant treatment after IORT. For five patients (27.8%), the time to the start or continuation of systemic treatment was ≤15 days and hence shorter than wound healing and adjuvant RT would have required.
Conclusion:
In accordance with previous series, this study demonstrates the effectiveness and safety of IORT in the management of brain metastases despite the small cohort and the retrospective characteristic of this analysis.
