Clinical research on the effects of gamma knife radiosurgery according to the localization of brain metastases

This study retrospectively reviewed records of patients referred to Pamukkale University's Department of Neurosurgery for Gamma Knife radiosurgery treatment of brain metastasis, from January 2016 to January 2023. We accessed the patients' data through the HBYS and E-NABIZ systems. Additionally, we measured and reported the location and volumes of brain tumors based on MRI findings. Men constituted the majority of the patient population at 73.3%, with an average age of 61.77. The primary involvement areas were predominantly the lung (65.8%) and breast (14%), with lower proportions in other areas. Lung primary cases were more common in men (26.2%) and breast primary cases in women (45.6%) (p=0.0001). There was no statistically significant difference between the primary involvement site and tumor response at the 12-month follow-up after Gamma Knife radiosurgery (p=0.050). At this follow-up, the average Karnofsky score was 76.67 for tumors with progressive behavior, compared to 80.66 for patients with a complete response (p=0.044). Both the RPA classification and Karnofsky scores were statistically significant predictors of mortality (p<0.050). In lung tumors, shrinkage was statistically significant in the frontal, parietal, and occipital lobes (r>0.50; p<0.050). Progressive tumors in the lung's temporal lobe tended to grow more aggressively at the 12-month check (r = 0.390; p = 0.040). In breast tumors, aggressive growth tendencies were observed in the cerebellum and parietal lobe during the 12-month follow-up (r>0.50; p<0.050) In conclusion, we found that tumors with lung and breast metastasis frequently involved the parietal lobe, cerebellum, and frontal lobe. Regarding tumor behavior, we observed notably high growth rates in the 44 patients who exhibited progressive behavior at the 12-month follow-up after Gamma Knife radiosurgery. We suggest that future studies should include a broader range of cancer subtypes and a larger number of patients from other primary cancer regions to validate and expand upon these findings.