Postsurgery HSRT Safer Than Whole-Brain RT for Brain Metastases
In an international cohort study on the outcomes of post-operative hypofractionated stereotactic radiotherapy (HSRT) to the resection cavity versus whole-brain RT in patients with brain metastases, HSRT had a favorable risk-benefit profile (JAMA Netw Open. 2020;3:e2021197).
“For brain metastases, the combination of neurosurgical resection and postoperative [HSRT] is an emerging therapeutic approach preferred to the prior practice of postoperative whole-brain radiotherapy. However, mature large-scale outcome data are lacking,” wrote Kerstin A. Eitz, PhD, Department of Radiation Oncology, Technical University of Munich, Germany, and colleagues.
A total of 558 patients (mean age, 61 years) with resected brain metastases treated between December 2003, and October 2019 were included in the study. Those we had prior cranial radiotherapy (including whole-brain radiotherapy) and early termination of treatment was excluded. Patients were given a median total dose of 30 Gy (range, 18-35 Gy) and a dose per fraction of 6 Gy.
The primary end points included overall survival (OS), local control, and the analysis of prognostic factors associated with OS and local control. The secondary end points were instant intracranial failure, distant progression, and the incidence of neurologic toxicity.
The median follow-up for this study was 12.3 months (interquartile range, 5.0-25.3 months). At 1 year, OS was 65%, 46% at 2 years, and 33% at 3 years, while LC was 84% at 1 year, 75% at 2, and 71% at 3 years.
Of those who underwent treatment, 48 (8.6%) had radiation necrosis, and 73 (13.1%) had leptomeningeal disease. Neurologic toxic events grade 3 or higher occurred in16 patients (2.8%) less than 6 months and 24 patients (4.1%) greater than 6 months following treatment.
Multivariate analysis found that a Karnofsky Performance Status score of 80% or greater (hazard ratio [HR], 0.61; 95% CI, 0.46-0.82; P <.001), 22 to 33 days between resection and radiotherapy (HR, 1.50; 95% CI, 1.07-2.10; P = .02), and a controlled primary tumor (HR, 0.69; 95% CI, 0.52-0.90; P = .007) were prognostic factors linked to overall survival. For local control, factors significant in the multivariate analysis were single brain metastasis (HR, 0.57; 95% CI, 0.35-0.93; P = .03) and a controlled primary tumor (HR, 0.59; 95% CI, 0.39-0.92; P = .02).
“To date, this cohort study includes one of the largest series of patients with brain metastases and postoperative HSRT and appears to confirm an excellent risk-benefit profile of local HSRT to the resection cavity. Additional studies will help determine radiation dose-volume parameters and provide a better understanding of synergistic effects with systemic and immunotherapies,” concluded Dr Eitz et al.—Alexandra Graziano