Reasons for uncontrolled orbital tumors after Gamma Knife surgery

Abstract Background To analyze the reasons for uncontrolled Gamma Knife surgery (GKS) of orbital tumors. If we can avoid selecting tumors that are easy to recur, the application of Gamma Knife in ophthalmology will be safer and more popular. Methods Retrospective clinical analysis of 72 patients with orbital tumors treated with GKS over a 10-year period from January 2010 to December 2020.The study included 29 males and 43 females with mean age of 42.3years (range 11–75 years).Collect the tumor type, tumor volume, clinical symptoms, GKS dose of all patients before GKS.25 cases were treated with surgery before GKS and had a clear pathological diagnosis; 47 cases were treated without surgery before GKS and a clinical diagnosis was made based on clinical features and imaging manifestations. Results After GKS, the volume increased in 39 cases, stabilized in 17 cases, and decreased in 16 cases.In the 16 cases with reduced volume, the average volume of was 3.35 (0.31–8.26) cm 3 ; The median margin dose is 11Gy (7-14Gy), and the median isodose curve is 50% (45%-50%).Of the 39 cases with volume growth, the mean volume was 17.37 (3.19–50.91) cm 3 , the median margin dose was 12 Gy (7–16 Gy), and the median isodose curve was 50% (45%-65%).Of the 39 patients who grew in size, 20 were reoperated, 10 underwent GKS again, and the remaining 9 were under clinical observation.Of the 20 cases of surgery after GKS,7 cases in which the postoperative pathological diagnosis was inconsistent with the clinical diagnosis at the time of GKS.The average Ki67 index of the patients at the time of surgery after GKS was 7.7%.No serious acute side effects were observed after GKS. Conclusions The following factors affect the efficacy of GKS: 1. orbital tumor volume; 2. orbital tumor type and Ki67 index; 3. GKS dose and parameters.