Functional-Based Resection Does Not Worsen Quality of Life in Patients with a Diffuse Low-Grade Glioma Involving Eloquent Brain Regions: A Prospective Cohort Study

OBJECTIVE: We assessed the impact of surgery on postoperative cognitive function and ability to work in adult patients with a diffuse low-grade glioma involving eloquent brain regions and having a functional-based maximal surgical resection using intraoperative cortico-subcortical mapping under awake conditions. METHODS: We prospectively included 39 consecutive patients with diffuse isocitrate dehydrogenase-mutant low-grade glioma without preoperative and adjuvant oncologic treatment and assessed preoperative (mean, 24.1 +/- 21.2 days before surgery) and postoperative (mean, 14.6 +/- 13.2 months after surgery) cognitive evaluations and ability to work together with clinical, imaging, therapeutic, and follow-up characteristics before tumor progression. RESULTS: None of the 3 patients without preoperative cognitive deficit had postoperative worsening. We observed a significant inverse interaction between worsened postoperative cognitive function and extent of resection: 80.0%, 18.8%, and 16.7% of worsening after partial, subtotal, and total resection, respectively (P = 0.020). We observed an independent interaction between improved postoperative cognitive function and extent of resection: 20.0%, 43.7%, and 44.4% of improvement after partial, subtotal, and total resection, respectively (P = 0.022). Of the employed patients, 61.8% were unable to work preoperatively and 82.4% resumed their employment postoperatively (mean, 6.9 +/- 5.5 months). We observed an independent interaction between postoperative ability to work, similar or superior to preoperative work capacity and extent of resection (P < 0.001): 20.0%, 87.5%, and 100% ability to work after partial, subtotal resection, and total resection. CONCLUSIONS: The extent of the functional-based surgical resection and the residual tumor for diffuse low-grade gliomas involving eloquent brain regions correlate with postoperative cognitive outcomes and return to work rates.