Gross Total Resection and Recurrence-Free Survival in Diffuse Gliomas: A Single-Center Cohort Study from Eastern Europe.

Background/Objectives: The independent contribution of extent of resection (EOR) to early recurrence in diffuse gliomas remains debated, as crude analyses are confounded by tumor biology, and real-world data from Eastern European centers are scarce. Methods: We retrospectively studied 283 consecutive adults with surgically treated diffuse gliomas (2021-2024) at a Romanian tertiary center. Primary endpoints were recurrence-free survival (RFS) at 1 and 2 years, evaluated as landmark endpoints; secondary endpoints were overall recurrence, reoperation, and reirradiation. Clinical, histopathological, surgical, imaging, and treatment variables were analyzed with complete-case Firth-penalized logistic regression. Results: Among evaluable patients, 70.6% (132/187) were recurrence-free at 1 year and 64.2% (120/187) at 2 years; overall recurrence occurred in 53.7% (139/259). After adjustment, gross total resection (GTR) was independently associated with higher odds of remaining recurrence-free at 1 year (OR 12.37, 95% CI 3.23-52.58; p < 0.001) and 2 years (OR 10.56; p < 0.001), as was subtotal resection (STR) at both time points (OR 4.15, 95% CI 1.17-16.16, p = 0.027; and OR 3.93, p = 0.027), versus partial resection/biopsy. Conclusions: EOR was independently associated with early RFS, supporting maximal safe resection as a primary surgical objective. The landmark endpoints were not evaluable in 96 of 283 patients, almost all of whom underwent biopsy or partial resection, so the odds ratios indicate the direction of the effect and not its precise magnitude. Overall recurrence, evaluable in 91.5% of the cohort, showed a concordant gradient. External validation is needed.