Clinical value of optimizing extent of resection in adult diffuse gliomas

Background and Introduction: Revision surgery for adult diffuse gliomas has benefits in terms of maximizing the extent of resection and providing accurate histopathological diagnosis. However, these benefits must be balanced against the potential higher morbidity of redo-surgery. Methodology: We retrospectively analyzed patients who underwent revision surgery for adult-type diffuse gliomas. Benefits (histological reclassification, and achievement of gross total resection i.e. GTR), and harm (major morbidity) were incorporated into a scoring system, and outcome categories were proposed. For the subset of glioblastomas (IDH wild-type) who underwent GTR, we also calculated the estimated increase in survival, conferred by the relook surgery. Results: There were 41 patients (M:F ratio of about 3.5), with a mean age of 35.4 years. GTR was achieved in 43.9 % and histopathological discordance seen in 46.3 %. Four (9.8 %) had major morbidity (including one death). Most (37/41) were categorized into the 'definitely benefitted' or 'benefitted' categories. Preoperative symptoms, raised ICP and comorbidities were more likely to predict subtotal resection, with resultant lower benefits from revision surgery. Glioblastomas were also less likely to have GTR, but in the subset that underwent GTR, there was an estimated survival benefit of 4-9 months. Conclusion: Revision surgery provides valuable benefits in selected patients having undergone an incomplete primary resection, by increasing the extent of resection (and thereby survival) and providing a more accurate histopathological diagnosis due to adequate tumour sampling, provided morbidity can be minimized.