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

Abstract

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

Methods and materials: A large BM was defined as ≥4 cm³ (2 cm in diameter) prior to the study. We reviewed the records of consecutive patients treated with single-fraction SRS alone or surgery with preoperative or postoperative SRS between 2005 and 2013 from 2 institutions.

Results: Overall, 213 patients with 223 treated large BMs were included; 66 BMs (30%) were treated with SRS alone and 157 (70%) with surgery and SRS (63 preoperatively and 94 postoperatively). The groups (SRS vs surgery and SRS) were well balanced except regarding lesion volume (median, 5.9 cm³ vs 9.6 cm³; P<.001), median number of BMs (1.5 vs 1, P=.002), median SRS dose (18 Gy vs 15 Gy, P<.001), and prior whole-brain radiation therapy (33% vs 5%, P<.001). The local recurrence (LR) rate was significantly lower with surgery and SRS (1-year LR rate, 36.7% vs 20.5%; P=.007). There was no difference in radiation necrosis (RN) by resection status, but there was a significantly increased RN rate with postoperative SRS versus with preoperative SRS and with SRS alone (1-year RN rate, 22.6% vs 5% and 12.3%, respectively; P<.001). OS was significantly higher with surgery and SRS (2-year OS rate, 38.9% vs 19.8%; P=.01). Both multivariate adjusted analyses and propensity score-matched analyses demonstrated similar results.

Conclusions: In this retrospective study, gross total resection with SRS was associated with significantly reduced LR compared with SRS alone for patients with large BMs. Postoperative SRS was associated with the highest rate of RN. Surgical resection with SRS may improve outcomes in patients with a limited number of large BMs compared with SRS alone. Further studies are warranted.