Surgery for brain metastases - real-world prognostic factors' association with survival

Background Surgical resection of brain metastases (BM) improves overall survival (OS) in selected patients. Selecting those patients likely to benefit from surgery is challenging. The Graded Prognostic Assessment (GPA) and the diagnosis-specific Graded Prognostic Assessment (ds-GPA) were developed to predict survival in patients with BM, but not specifically to guide patient selection for surgery. Our aim was to evaluate the feasibility of preoperative GPA/ds-GPA scores and assess variables associated with OS. Methods We retrospectively reviewed first-time surgical resection of BM from solid tumors at a Norwegian regional referral center from 2011 to 2018. Results Of 590 patients, 51% were female and median age was 63 years. Median OS was 10.3 months and 74 patients (13%) died within three months after surgery. Preoperatively tumor origin was unknown in 20% of patients. A GPA score could be calculated for 92% of the patients preoperatively, but could not correctly predict survival. A ds-GPA score could be calculated for 46% of patients. Multivariable regression analysis revealed shorter OS in patients with higher age, worse functioning status, colorectal primary cancer compared to lung cancer, presence of extracranial metastases, and more than four BM. Patients with preoperative progressive extracranial disease or synchronous BM had shorter OS compared to patients with stable extracranial disease. Conclusion Ds-GPA could be calculated in less than half of patients preoperatively and GPA poorly identified patients which had minimal benefit of surgery. Including status of extracranial disease improve prognostication and therefore selection to surgery for brain metastases.