Intraoperative radiotherapy (IORT) for surgically resected brain metastases: outcome analysis of an international cooperative study

• Published in: Journal of neuro-oncology Vol. 145; no. 2; pp. 391 - 397
• Main Authors: Cifarelli, Christopher P., Brehmer, Stefanie, Vargo, John Austin, Hack, Joshua D., Kahl, Klaus Henning, Sarria-Vargas, Gustavo, Giordano, Frank A.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.11.2019; Springer Nature B.V
• Subjects: Aged; Brain cancer; Brain Neoplasms - radiotherapy; Brain Neoplasms - secondary; Brain Neoplasms - surgery; Carcinoma, Non-Small-Cell Lung - radiotherapy; Carcinoma, Non-Small-Cell Lung - secondary; Carcinoma, Non-Small-Cell Lung - surgery; Clinical Study; Female; Frontal lobe; Humans; Intraoperative Period; Kaplan-Meier Estimate; Lung cancer; Male; Medicine; Medicine & Public Health; Metastases; Metastasis; Middle Aged; Neurology; Non-small cell lung carcinoma; Oncology; Radiation therapy; Radiosurgery; Radiotherapy - adverse effects; Radiotherapy - methods; Retrospective Studies; Small cell lung carcinoma; Statistical analysis; Surgery; Treatment Outcome; Brain metastases; IORT; Intraoperative radiotherapy
• ISSN: 0167-594X; 1573-7373; 1573-7373
• DOI: 10.1007/s11060-019-03309-6

Background and objective The ideal delivery of radiation to the surgical cavity of brain metastases (BMs) remains the subject of debate. Risks of local failure (LF) and radiation necrosis (RN) have prompted a reappraisal of the timing and/or modality of this critical component of BM management. IORT delivered at the time of resection for BMs requiring surgery offers the potential for improved local control (LC) afforded by the elimination of delay in time to initiation of radiation following surgery, decreased uncertainty in target delineation, and the possibility of dose escalation beyond that seen in stereotactic radiosurgery (SRS). This study provides a retrospective analysis with identification of potential predictors of outcomes. Methods Retrospective data was collected on patients treated with IORT immediately following surgical resection of BMs at three institutions according to the approval of individual IRBs. All patients were treated with 50kV portable linear accelerator using spherical applicators ranging from 1.5 to 4.0 cm. Statistical analyses were performed using IBM SPSS with endpoints of LC, DBC, incidence of RN, and overall survival (OS) and p < 0.05 considered significant. Results 54 patients were treated with IORT with a median age of 64 years. The most common primary diagnosis was non-small cell lung cancer (40%) with the most common location in the frontal lobe (38%). Median follow-up was 7.2 months and 1-year LC, DBC, and OS were 88%, 58%, and 73%, respectively. LMD was identified in 2 patients (3%) and RN present in 4 patients (7%). The only predictor of LC was extent of resection with 1-year LC of 94% for GTR versus 62% for STR (p = 0.049). Conclusions IORT is a safe and effective means of delivering adjuvant radiation to the BM resection cavities with high rates of LC and low incidence of RN. Further studies are warranted directly comparing LC outcomes to SRS.