Complications after stereotactic radiosurgery for brain metastases: Incidences, correlating factors, treatments and outcomes.

Abstract

Complications after stereotactic radiosurgery (SRS) for brain metastases (BMs) were analyzed in detail using our database including nearly 3000 BM patients. This was an institutional review board-approved, retrospective cohort study using our prospectively accumulated database including 3271 consecutive patients who underwent gamma knife SRS for BMs during the 1998-2016 period. Excluding four patients lost to follow-up, 112 with three-staged treatment and 189 with post-operative irradiation, 2966 who underwent a single-session of SRS only as radical irradiation were studied. The overall median survival time after SRS was 7.8 (95% CI; 7.4-8.1) months. Post-SRS complications occurred in 86 patients (2.9%) 1.9-211.4 (median; 24.0, IQR; 12.0-64.6) months after treatment. RTOG neurotoxicity grades were 2, 3 and 4 in 58, 25 and 3 patients, respectively. Cumulative incidences determined with a competing risk analysis were 1.4%, 2.2%, 2.4%, 2.6% and 2.9% at the 12th, 24th, 36th, 48th and 60th post-SRS month, respectively. Among various pre-SRS clinical factors and radiosurgical parameters, multivariable analyses demonstrated solitary tumor (Adjusted HR; 0.584, 95% CI; 0.381-0.894, p = 0.0133), controlled primary cancer (Adjusted HR; 2.595, 95% CI; 1.646-4.091, p < 0.0001), no extra-cerebral metastases (Adjusted HR; 1.608, 95% CI; 1.028-2.514, p = 0.0374), KPS ≥80% (Adjusted HR; 2.715, 95% CI; 1.245-5.924, p = 0.0121) and largest tumor volume ≥3.3 cc (Adjusted HR; 0.516, 95% CI; 0.318-0.836, p = 0.0072) to be independently significant predictors of a higher incidence of complications. The post-SRS complication incidence is acceptably low (2.9%). Meticulous long-term follow-up after SRS is crucial for all patients.