Background
supratotal resection is advocated in lower-grade-gliomas (LGGs) based on theoretical advantages, but with limited verification of functional risk and data on oncological outcomes. We assessed the association of supratotal resection in molecular-defined LGGs with oncological outcomes.
Methods
460 presumptive LGGs included; 404 resected; 347 were LGGs, 319 IDH-mutated, 28 wildtype. All patients had clinical, imaging, molecular data. Resection aimed at supratotal resection without any patient or tumor a-priori selection. The association of Extent-of-Resection (EOR), categorized on volumetric-FLAIR-images as residual-tumor-volume, along with post-surgical-management with Progression-free-survival (PFS), malignant-progression-free-survival (MPFS), and Overall-Survival (OS) assessed by univariate, multivariate, propensity-score-analysis. The study mainly focused on IDH-mutated-LGGs, the “typical LGGs”.
Results
Median follow-up:6.8 years(IQR:5-8). Out of 319 IDH-mutated-LGGs, 190 (59.6%) progressed, median PFS:4.7 years(95%CI:4–5.3). Total and supratotal resection obtained in 39% and 35% of patients of IDH1-mutated tumors. In IDH-mutated, most patients in partial/subtotal group progressed, 82.4% in total, only 6 (5.4%) in supratotal. Median PFS was 29 months(95%CI:25-36) in subtotal, 46 months(95%CI:38-48) in total, while at 92 months, PFS in supratotal was 94.0%. There was no association with molecular-subtypes and grade. At random-forest-analysis, PFS strongly associated with EOR,RT, previous treatment. In the propensity-score analysis, EOR associated with PFS (HR,0.03;95%CI,0.01-0.13). MPFS occurred in 32.1% of subtotal-total groups; 1 event in supratotal. EOR, grade-III, previous treatment correlated to MPFS. At random-forest analysis, OS associated with EOR as well.
Conclusions
Supratotal resection strongly associated with PFS, MPFS and OS in LGGs, regardless of molecular subtypes and grade, right from the beginning of clinical presentation.