Evaluation of Presurgical Outcome Predictors in Oncological Neurosurgery

Brain tumor (BT) resection carries a significant risk of postoperative functional impairment. Existing surgical complexity scales (e.g., Milan Complexity Scale) do not account for factors such as preoperative tumoral edema or deep tumor location (DTL), which may influence outcome. This study evaluates whether these variables improve prediction of 6-month postoperative functional outcomes.

We conducted a prospective multicenter cohort study including 231 patients undergoing BT resection. Preoperative variables (tumor size, eloquence, deep location, vascular/cranial nerve manipulation, posterior fossa location, edema) were collected. Functional status was assessed preoperatively and six months postoperatively using the Karnofsky Performance Scale and modified Rankin Scale. Patients were grouped based on whether their 6-month Karnofsky Performance Scale/modified Rankin Scale scores worsened versus remained stable/improved. Correlations and multivariate logistic regression identified predictors of functional decline. Hierarchical clustering explored risk combinations.

Among 231 patients, 59% had tumors located in eloquent areas, 18% in DTL and 39% presented with edema. Both preoperative edema and DTL were significantly associated with functional deterioration at six months. Multivariate analysis identified edema (P = 0.011), eloquent region involvement (P = 0.037), vascular manipulation (P = 0.040), tumor size >4 cm (P = 0.041), and DTL (P = 0.046) as independent predictors of decline. Cluster analysis showed that combinations of adverse factors-particularly edema, large size, deep or posterior fossa location, and neurovascular manipulation-were associated with the highest risk of poor outcomes.

Preoperative tumoral edema and DTL are under-recognized predictors of functional deterioration after BT surgery. Their inclusion in preoperative risk models could enhance prognostic accuracy and guide surgical decision-making in neuro-oncology.