Abstract: Single Fraction Stereotactic Radiosurgery (SRS) Alone

Abstract: Single Fraction Stereotactic Radiosurgery (SRS) Alone Versus Surgical Resection and SRS for Large Brain Metastases: A Multi-institutional Analysis

Co-written by SERO Doctors:
Roshan S. Prabhu, MD
Scott P. Lankford, MD
Robert McCammon, MD
Benjamin J. Moeller, MD, PhD
John H. Heinzerling, MD
Carolina Elizabeth Fasola, MD
Stuart H. Burri, MD

Co-written by:
Robert H. Press
Danielle M. Boselli
James T. Symanowski
Kirtesh R. Patel
Anthony L. Asher
Ashley L. Sumrall
Zachary S. Buchwald
Walter J. Curran Jr.
Hui-Kuo G. Shu
Ian R. Crocker

• Published on the Internal Journal of Radiation Oncology – View Abstract

Stereotactic radiosurgery (SRS) dose is limited by brain metastasis (BM) size. The study goal was to retrospectively determine if there is a benefit for intracranial outcomes and overall survival (OS) for gross total resection (GTR) with single fraction SRS versus SRS alone for patients with large BM.

Large BM was defined as ≥4 cc (2 cm diameter) prior to the study. The records of consecutive patients treated with single fraction SRS alone or surgery with pre-operative (pre-op SRS) or post-operative SRS (post-op SRS) between 2005-2013 from 2 institutions were reviewed.

Overall, 213 patients with 223 treated large BM were included; 66 (30%) were treated with SRS alone and 157 (70%) with surgery and SRS (63 pre-op, 94 post-op). Groups (SRS vs. surgery and SRS) were well balanced except for lesion volume (median 5.9cc vs. 9.6cc, p<0.001), median number of BM (1.5 vs. 1, p=0.002), median SRS dose (18 vs. 15Gy, p<0.001), and prior WBRT (33% vs. 5%, p<0.001), respectively. Local recurrence (LR) was significantly lower with surgery and SRS (1-year LR: 36.7% vs. 20.5%, p=0.007). There was no difference in radiation necrosis (RN) by resection status, but post-op SRS had significantly increased RN rate compared with pre-op SRS or SRS alone (1-year RN: 22.6%, 5%, 12.3%, respectively, p<0.001). OS was significantly higher with surgery and SRS (2-year OS: 38.9% vs. 19.8%, p=0.01). Both multivariable adjusted analyses and propensity score matched analyses demonstrated similar results.

In this retrospective study, GTR with SRS was associated with significantly reduced LR compared with SRS alone for patients with large BM. Post-op SRS was associated with the highest rate of RN. Surgical resection with SRS may improve outcomes in patients with a limited number of large BM compared with SRS alone. Further studies are warranted.

Prabhu RS, Press RH, Patel KR, Boselli DM, Symanowski JT, Lankford SP, McCammon RJ, Moeller BJ, Heinzerling JH, Fasola CE, Asher AL, Sumrall AL, Buchwald ZS, Curran WJ, Shu HG, Crocker IR, Burri SH. Single Fraction Stereotactic Radiosurgery (SRS) Alone Versus Surgical Resection and SRS for Large Brain Metastases: A Multi-institutional Analysis. Int J Radiat Oncol Biol Phys. Accepted April 3, 2017. In press.