(P111) Single-Isocenter Frameless Volumetric-Modulated Arc Radiosurgery for Multiple Intracranial Metastases

April 30, 2015

Single-isocenter, frameless VMAR for multiple intracranial metastases can produce clinical outcomes comparable with those of conventional radiosurgery techniques.

Steven Lau, MD, PhD, Kaveh Zakeri, MD, Xiao Zhao, MD, Ruben Carmona, MAS, Erik Knipprath, Daniel R. Simpson, MD, Sameer K. Nath, MD, Gwe-Ya Kim, PhD, Parag Sanghvi, MD, Jona A. Hattangadi, MD, Clark C. Chen, MD, PhD, Kevin T. Murphy, MD; University of California, San Diego; University of California, Davis; Yale University

PURPOSE: Stereotactic radiosurgery is a well-accepted treatment for patients with intracranial metastases, but outcomes with volumetric-modulated arc radiosurgery (VMAR) are poorly described. We report our initial clinical experience applying a novel single-isocenter technique to frameless VMAR for simultaneous treatment of multiple intracranial metastases.

METHODS: Between 2009 and 2011, a total of 15 patients underwent frameless VMAR for multiple intracranial metastases using a single, centrally located isocenter. Among them, three patients were treated for progressive or recurrent intracranial disease. A total of 62 metastases (median 3 per patient, range 2–13) were treated to a median dose of 20 Gy (range: 15–30 Gy). Three patients were treated with fractionated SRS. Follow-up, including clinical examination and magnetic resonance imaging (MRI), occurred every 3 months.

RESULTS: Median follow-up for all patients was 7.1 months (range: 1.1–24.3 mo), with 11 patients (73.3%) followed until death. For the remaining four patients alive at the time of analysis, median follow-up was 19.6 months (range: 9.2–24.3 mo). Overall survival (OS) at 6 months was 60.0% (95% confidence interval [CI], 40.3%–88.2%). Local control rates at 6 and 12 months were 91.7% (95% CI, 84.6%–100.0%) and 81.5% (95% CI, 67.9%–100.0%), respectively. Regional failure was observed in nine patients (60.0%), and seven patients (46.7%) received salvage therapy. Grade ≥ 3 treatment-related toxicity was not observed. Median total treatment time was 7.2 minutes (range: 2.8–13.2 min).

CONCLUSIONS: Single-isocenter, frameless VMAR for multiple intracranial metastases can produce clinical outcomes comparable with those of conventional radiosurgery techniques.

Proceedings of the 97th Annual Meeting of the American Radium Society - americanradiumsociety.org