Interactive Effects of Molecular, Therapeutic, and Patient Factors on Outcome of Diffuse Low-Grade Glioma

PURPOSEIn patients with diffuse low-grade glioma (LGG), the extent of surgical tumor resection (EOR) has a controversial role, in part because a randomized clinical trial with different levels of EOR is not feasible.METHODSIn a 20-year retrospective cohort of 392 patients with IDH-mutant grade 2 glioma, we analyzed the combined effects of volumetric EOR and molecular and clinical factors on overall survival (OS) and progression-free survival by recursive partitioning analysis. The OS results were validated in two external cohorts (n = 365). Propensity score analysis of the combined cohorts (n = 757) was used to mimic a randomized clinical trial with varying levels of EOR.RESULTSRecursive partitioning analysis identified three survival risk groups. Median OS was shortest in two subsets of patients with astrocytoma: those with postoperative tumor volume (TV) > 4.6 mL and those with preoperative TV > 43.1 mL and postoperative TV & LE; 4.6 mL. Intermediate OS was seen in patients with astrocytoma who had chemotherapy with preoperative TV & LE; 43.1 mL and postoperative TV & LE; 4.6 mL in addition to oligodendroglioma patients with either preoperative TV > 43.1 mL and residual TV & LE; 4.6 mL or postoperative residual volume > 4.6 mL. Longest OS was seen in astrocytoma patients with preoperative TV & LE; 43.1 mL and postoperative TV & LE; 4.6 mL who received no chemotherapy and oligodendroglioma patients with preoperative TV & LE; 43.1 mL and postoperative TV & LE; 4.6 mL. EOR & GE; 75% improved survival outcomes, as shown by propensity score analysis.CONCLUSIONAcross both subtypes of LGG, EOR beginning at 75% improves OS while beginning at 80% improves progression-free survival. Nonetheless, maximal resection with preservation of neurological function remains the treatment goal. Our findings have implications for surgical strategies for LGGs, particularly oligodendroglioma.

Automated summary

In patients with diffuse low-grade glioma, the extent of surgical tumor resection has a controversial role in prognosis, but a randomized clinical trial is not feasible to determine different levels of resection.