Association of Extent of Resection and Functional Outcomes in Diffuse Low-Grade Glioma: Systematic Review & Meta-Analysis
Authors: Elsheikh Mustafa , Bridgman Elsie , Lavrador Jose Pedro , Lammy Simon , Chung Poon Michael Tin 
Published: September 2022

AbstractBackgroundSurgical resection offers survival benefits in patients with diffuse low-grade glioma (DLGG) but its association with functional outcomes is uncertain. This systematic review assessed functional outcomes associated with extent of resection (EoR) in adults with DLGG.MethodsWe searched Medline, Embase and CENTRAL on the 19th of February 2021 for observational studies reporting functional outcomes after surgical resection for patients aged ≥18 years with a new diagnosis of supratentorial DLGG according to any World Health Organization classification of primary brain tumors. The Newcastle-Ottawa Scale (NOS) informed our risk of bias assessments. The proportion of patients returning to work within 12 months entered a random-effects meta-analysis. PROSPERO registration number CRD42021238387.ResultsThere were seven eligible moderate to high-quality (NOS >6) observational studies identified from 1,183 records involving 234 patients with DLGG. Functional outcomes reported included neurocognition (n=2 studies), performance status (n=3), quality of life (QoL) (n=1) and return to work (n=6). The proportion of patients who returned to work within 12 months of surgery was 84% (95% confidence interval [CI] 50-96%, I-squared=38%, 5 studies) for gross total resection, 66% (95% CI 14-96%, I2=57%, 5 studies) for subtotal resection, and 31% (95% CI 4-82%, I2= 0%, 4 studies) for partial resection. There was insufficient data on other functional outcomes for quantitative synthesis.ConclusionA higher proportion of DLGG patients returned to work following gross total resection compared with those who had a subtotal or partial resection. Further studies with standardized assessments can clarify the association between EoR and different functional outcomes.Importance of the StudyThe association between lower residual tumor volume and better survival in people with diffuse low-grade glioma (DLGG) has driven surgical research into maximizing resection. However, innovative interventions should be evaluated against both oncological outcomes and functional outcomes. This systematic review included all studies reporting post-operative functional outcomes stratified by the extent of resection in people aged ≥18 years with DLGG. Two studies reported neurocognition, three reported performance status, one reported quality of life, and six reported return-to-work. Our meta-analysis demonstrated a higher proportion of patients returning to work within 12 months for those who had gross total resection (84%) compared to subtotal (66%) and partial (31%) resections. Our results suggest that increased EoR may be associated with return-to-work, but direct comparative studies should verify this finding and could examine other important functional outcomes.Key PointsSeven studies reported functional outcomes stratified by EoR in DLGG patients.Return-to-work (RTW) was the most reported functional outcome.84% undergoing GTR of DLGG RTW within 12 months compared to STR (66%) or PR (31%).