Surgery followed by hypofractionated radiosurgery on the tumor bed in oligometastatic patients with large brain metastases. Results of a Phase II study.

Abstract

PURPOSE\nThis prospective phase II study assessed safety and feasibility of surgery followed by hypofractionated radiosurgery (HSRS) on the tumor bed in oligometastatic patients with single large brain metastases (BMs).\n\n\nMETHODS AND MATERIALS\nBetween June 2015 and May 2018 101 patients were enrolled. Oligometastatic disease was defined by a maximum of 5 extracranial metastatic lesions. HSRS was performed within 1 month from surgery and consisted of 30 Gy/3 fractions. Local control, occurrence of new BMs, overall survival, and treatment related toxicities were assessed.\n\n\nRESULTS\nAt a median follow up time of 26 months local recurrence occurred in 6 (5.9%) patients. Six-month,1,2-year local control rates were 100%, 98.9%±1.1%, 85.9%±0.6%. New BMs occurred in 39 (38.6%) patients; median brain-distant-progression time, 6-month,1,2-year brain-distant-progression rates were 39 months (95%CI 19-39months), 17%±3.7%, 31.4%±4.8%, and 42.5%±5.9%. At the last observation time 50 (49.5%) patients are alive and 51 (50.5%) dead; 10 patients died for neurological cause and 40 for systemic progression. Median overall survival time, 6-month,1,2-year OS rates were 22 months (95%CI20-30months), 95%±2.1%, 81.9%±3.8%, and 46.6%±6%. Infratentorial site, residual-tumor-volume, longer interval time between primary diagnosis and occurrence of BMs, and oligometastatic disease status significantly influenced outcome. Grade 2-3 radionecrosis occured in 26 patients. Neurocognitive functions remained stable or in some cases improved.\n\n\nCONCLUSIONS\nSurgery followed by HSRS on the tumor bed, is a safe and effective approach, affording good brain control with acceptable toxicities. As for extracranial metastatic site, the outcome of patients with BMs can benefit by a local ablative treatment, in the context of an oligometastatic disease.