Anamnestic radiological metastases outcome surgical score (ARMO-S). A purpose of a predictive surgical scoring system for brain metastases

Background: Several risk stratification scores have been suggested to aid prognostication and guide treatment strategies for brain metastases (BMs). However, the current scores do not focus on the specific neurosurgical population, therefore not predicting short-term mortality and postoperative performance status. Methods: This retrospective observational study of 362 consecutive patients treated with surgery for BMs aims to identify the factors associated with post-surgical outcomes and propose a surgery-specific prognostic score for patients with BMs candidate for open surgery. Results: Factors significantly associated with OS and performance status in multivariate analysis were age, KPS, surgical site, synchronous debut of BM, number, tumor volume, seizure, extra-cranial metastases, and deep-seated location. The variables were incorporated into the Anamnestic Radiological Metastases Outcome Surgical score (ARMO-S). The values range between 0 and 10. Patients were divided into two groups (low-risk and high-risk) based on each significant subgroup's median survival and performance status with an optimal cutoff value determined as 4. The two groups have significant differences in OS (9.6 versus 14 months, p = 0.0048) postoperative KPS (90 versus 70, p = 0.012) and KPS at last follow-up evaluation (75 versus 30, p < 0.001) CONCLUSION: ARMO-S is a simple and comprehensive score for BM patients selected for neurosurgery, as it incorporates the main factors of the most important prognostic scores, implementing them with more surgery-specific predictive elements such as tumor location and volume, presence of seizures at onset, and involvement of eloquent brain areas.