# Can we make it up? - second-look surgery due to post-operative residual tumour in patients diagnosed with diffuse glioma

## TL;DR

This study shows that early second surgeries for leftover tumor in diffuse glioma patients can lead to better tumor removal and improved survival without harming their functional health.

## Contribution

The study introduces the effectiveness of early second-look surgery for residual diffuse glioma tumors in achieving maximal resection and better survival.

## Key findings

- Second-look surgery improved resection status from submaximal to maximal in 86.96% of patients.
- Residual tumor volumes decreased significantly for both T1-CE and T2-nCE components.
- Glioblastoma patients with RANO class 1 after second surgery had longer survival than those with RANO class 2B.

## Abstract

Complete resection (CR) of contrast-enhancing (CE) and non-contrast-enhancing (nCE) tumour compartments is a key prognostic factor in diffuse gliomas. However, despite an intraoperative impression of CR, early postoperative MRI may reveal residual tumour. This study evaluated outcomes of patients undergoing early second-look surgery for unplanned residual tumour volume.

Patients undergoing surgery for diffuse gliomas between 2013 and 2023 were screened for surgical re-intervention within six weeks after initial resection. Patients undergoing early second-look surgery due to unplanned residual tumour on postoperative MRI were included. Volumetric MRI analyses, RANO resection classification, functional neurological outcomes, perioperative complications, and survival were assessed.

Among 1.558 glioma patients (CNS WHO grade 2–4), 447 underwent multiple surgeries, of whom 46 received second-look surgery for residual tumour. Resection status shifted from 80.4% submaximal after first surgery to supramaximal or maximal resection in 86.96% after second-look surgery. Residual tumour volumes were significantly reduced for both T1-CE and T2-nCE components (p < .001). Functional and neurological status remained stable (KPS and NIHSS, p > .5). In newly diagnosed glioblastoma patients (n = 28), RANO class 1 after second-look surgery was associated with longer overall survival compared to RANO 2B (13.8 vs. 8.0 months; p = .043). The 2- and 3-year OS rates were 33.34% and 16.67% in RANO class 1, while no patients in RANO class 2B survived beyond 2 years.

Early second-look surgery for unplanned residual tumour enables a high rate of (supra-)maximal resections without compromising functional outcomes and may improve survival in selected patients.