In a U.S. single-institution study reported in The Lancet Oncology, Mahajan et al found that stereotactic radiosurgery to the surgical cavity reduced local recurrence vs observation in patients with completely resected brain metastases.
In the trial, 128 evaluable patients at MD Anderson Cancer Center were randomized between August 2009 and February 2016 to undergo stereotactic radiosurgery of the resection cavity within 30 days of surgery (n = 63) or observation (n = 65). Patients had to have complete resection of one to three brain metastases, with a resection cavity maximum diameter of ≤ 4 cm. The primary endpoint was time to local recurrence in the resection cavity on blinded central review of brain magnetic resonance imaging by the study neuroradiologist in the modified intention-to-treat population.
Median follow-up was 11.1 months. Rates of 12-month freedom from local recurrence were 72% (95% confidence interval [CI] = 60%–87%) in the stereotactic radiosurgery group vs 43% (95% CI = 31%–59%) in the observation group (hazard ratio = 0.46, P = .015). Median time to local recurrence was not reached (95% CI = 15.6 months to not estimable) in the stereotactic radiosurgery group and 7.6 months (95% CI = 5.3 months to not estimable) in the observation group. Whole-brain radiotherapy was subsequently used in 38% of the stereotactic radiosurgery group and 46% of the observation group. No adverse events or treatment-related deaths were observed in either group.
The investigators concluded: “[Stereotactic radiosurgery] of the surgical cavity in patients who have had complete resection of one, two, or three brain metastases significantly lowers local recurrence compared with that noted for observation alone. Thus, the use of [stereotactic radiosurgery] after brain metastasis resection could be an alternative to whole-brain radiotherapy.”
The study was funded by the National Institutes of Health.
Ganesh Rao, MD, of the Neurosurgery Department, The University of Texas MD Anderson Cancer Center, is the corresponding author of The Lancet Oncology article.