Identification of risk factors associated with leptomeningeal disease after resection of brain metastases

OBJECTIVE Resection of brain metastases (BMs) may be associated with increased risk of leptomeningeal disease (LMD). This study examined rates and predictors of LMD, including imaging subtypes, in patients who underwent resec-tion of a BM followed by postoperative radiation.METHODS A retrospective, single-center study was conducted examining overall LMD, classic LMD (cLMD), and nodular LMD (nLMD) risk. Logistic regression, Cox proportional hazards, and random forest analyses were performed to identify risk factors associated with LMD.RESULTS Of the 217 patients in the cohort, 47 (21.7%) developed postoperative LMD, with 19 cases (8.8%) of cLMD and 28 cases (12.9%) of nLMD. Six-, 12-, and 24-month LMD-free survival rates were 92.3%, 85.6%, and 71.4%, respec-tively. Patients with cLMD had worse survival outcomes from the date of LMD diagnosis compared with nLMD (median 2.4 vs 6.9 months, p = 0.02, log-rank test). Cox proportional hazards analysis identified cerebellar/insular/occipital loca- tion (hazard ratio [HR] 3.25, 95% confidence interval [CI] 1.73-6.11, p = 0.0003), absence of extracranial disease (HR 2.49, 95% CI 1.27-4.88, p = 0.008), and ventricle contact (HR 2.82, 95% CI 1.5-5.3, p = 0.001) to be associated with postoperative LMD. A predictive model using random forest analysis with an area under the receiver operating charac-teristic curve of 0.87 in a test cohort identified tumor location, systemic disease status, and tumor volume as the most important factors associated with LMD.CONCLUSIONS Tumor location, absence of extracranial disease at the time of surgery, ventricle contact, and in-creased tumor volume were associated with LMD. Further work is needed to determine whether escalating therapies in patients at risk of LMD prevents disease dissemination.