Association of Extent of Resection and Functional Outcomes in Diffuse Low-Grade Glioma: Systematic Review & Meta-Analysis

Background: Surgical 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.
Methods: We searched Medline, Embase and CENTRAL on the 19 th 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.
Results: There 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.
Conclusion: A 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.