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Frameless, Real-Time, Surface Imaging-Guided Radiosurgery: Clinical Outcomes for Brain Metastases

Pan, Hubert MS*; Cerviño, Laura I. PhD*; Pawlicki, Todd PhD*; Jiang, Steve B. PhD*; Alksne, John MD*,‡; Detorie, Nicole PhD*; Russell, Michelle RN*; Carter, Bob S. MD, PhD; Murphy, Kevin T. MD*; Mundt, Arno J. MD*; Chen, Clark MD, PhD*,‡; Lawson, Joshua D. MD

doi: 10.1227/NEU.0b013e3182647ad5
Research-Human-Clinical Studies
CNS University of Neurosurgery

BACKGROUND: Frameless stereotactic radiosurgery is commonly used to treat intracranial metastases, but mask-based immobilization can be uncomfortable for patients.

OBJECTIVE: To describe the clinical outcomes using a novel real-time, frameless, surface imaging--guided radiosurgery (SIG-RS) technique to treat brain metastases.

METHODS: Data were prospectively gathered for 44 consecutive patients totaling 115 intracranial metastases treated with SIG-RS in a median of 1 fraction (range, 1-5) to a median dose of 20 Gy (range, 15-30 Gy). Local control, regional control, and overall survival were estimated by the Kaplan-Meier method.

RESULTS: Median follow-up for all patients was 6.0 months (range, 0.3-21.6 months), with 31 of 44 (70%) deceased at the time of analysis. The 35 patients (80%) with follow-up imaging totaled 88 lesions evaluable for local control. Actuarial 6- and 12-month local control was 90% (95% confidence interval, 82-98) and 76% (95% confidence interval, 60-91), respectively. Regional failure was observed in 16 patients (46%). The median actuarial overall survival was 7.7 months (95% confidence interval, 5.7-9.7). Analysis of the subset of 22 patients (55 lesions) who received SIG-RS alone (no prior treatment) in a single fraction yielded comparable clinical outcomes. Grade 3 or greater toxicity occurred in 4 patients (9%). The median treatment time from beam on to beam off was 15 minutes (range, 3-36 minutes).

CONCLUSION: SIG-RS for treating intracranial metastases can produce clinical outcomes comparable to those with conventional frame-based and frameless stereotactic radiosurgery techniques while providing greater patient comfort with an open-faced mask and fast treatment times.

ABBREVIATIONS: CBCT, cone-beam computed tomography

CI, confidence interval

LINAC, linear accelerator

RPA, recursive partitioning analysis

SIG-RS, surface imaging-guided radiosurgery

SRS, stereotactic radiosurgery

WBRT, whole-brain radiation therapy

*Department of Radiation Oncology, Center for Advanced Radiotherapy Technologies and

Department of Neurosurgery, University of California San Diego, La Jolla, California

Correspondence: Joshua D. Lawson, MD, Chief, Central Nervous System and Brain/Body Radiation Therapy Services, Department of Radiation Oncology, University of California San Diego, 3960 Health Sciences Dr, MC0865, La Jolla, CA 92093-0843. E-mail: jlawson@ucsd.edu; or Clark Chen, MD, PhD, Department of Neurosurgery University of California San Diego, 3960 Health Sciences Dr, MC0865, La Jolla, CA 92093-0843. E-mail: clarkchen@ucsd.edu

Received February 26, 2012

Accepted May 30, 2012

Copyright © by the Congress of Neurological Surgeons