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What Factors Predict the Response of Larger Brain Metastases to Radiosurgery?

Yang, Huai-che MD*§; Kano, Hideyuki MD, PhD*‡; Lunsford, L Dade MD*‡; Niranjan, Ajay MCh*‡; Flickinger, John C MD*†; Kondziolka, Douglas MD*‡

doi: 10.1227/NEU.0b013e318207a58b
Research-Human-Clinical Studies

BACKGROUND: Approximately 20 to 40% of patients with systemic malignancies develop brain metastases.

OBJECTIVE: To assess the potential role of stereotactic radiosurgery (SRS) for larger metastatic brain tumors, we reviewed our recent experience.

METHODS: Between 2004 and 2008, 70 patients with a metastatic brain tumor larger than 3 cm in maximum diameter underwent Gamma knife SRS. Thirty-three patients had received previous whole brain radiation therapy (WBRT) and 37 received only SRS.

RESULTS: The overall median follow-up was 8.1 months. At the first planned imaging follow-up at 2 months, 29 (41%) tumors had >50% volume reduction, 22 (31%) had 10 to 50% volume reduction, and 19 (28%) were stable or larger. We also evaluated brain edema using MRI T2 images. In 11 patients (16%) the peritumoral edema volume was reduced by more than 50%, in 25 (36%) it was reduced by 10 to 50%, in 21 (30%) it was stable, and in 13 (19%) it was increased. Twenty (36%) discontinued corticosteroids by the time of first imaging follow-up. Because of persistent symptoms, 7 patients (10%) required a craniotomy to remove the tumor. Tumor volume reduction (>50%) was associated with a single metastasis (P = .012), no previous WBRT (P = .002), and a tumor volume <16 cm3 (P = .002). The better peritumoral edema volume reduction (>50%) was associated with a single metastasis (P = .024), no previous WBRT (P = .05), and breast cancer histology (P = .044).

CONCLUSION: Surgical resection remains the primary approach for larger brain metastases if feasible. Tumor volume is a better indicator than maximum diameter. Tumor volume and edema responded better in patients who underwent SRS alone.

*Department of Neurological Surgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; †Department of Radiation Oncology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; ‡Center for Image-Guided Neurosurgery, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania; §Department of Neurosurgery, Taipei Veterans General Hospital, Taipei, Taiwan

Received, October 20, 2009.

Accepted, July 23, 2010.

Correspondence: Douglas Kondziolka, MD, University of Pittsburgh, Suite B-400, UPMC Presbyterian, 200 Lothrop Street, Pittsburgh, PA 15213. E-mail: kondds@upmc.edu

Copyright © by the Congress of Neurological Surgeons