Tag: Tumor burden

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Prediction of Diffuse High-Grade Glioma Survival Outcomes Using Preoperative Whole-Brain Tractography–Based Resectability Metrics

Neurosurgery 98:836–847, 2026

This study presents novel whole-brain tractography (WBT)–derived resectability metrics—resectability index (RI) and unresectable tumor volume (UTV), plus modified versions mRI and mUTV—calculated from preoperative diffusion imaging to estimate how much of diffuse high-grade gliomas (HGG) can be safely resected. Metrics are derived by quantifying tumor overlap with critical white-matter tracts and deep structures, and compared with conventional postoperative measures.

Using retrospective data from 146 tumors (84 with WBT), mRI and mUTV strongly predicted biopsy versus resection and correlated with extent of resection, residual tumor, and overall survival. Accelerated failure time models incorporating mUTV/mRI provided accurate preoperative survival predictions, outperforming conventional metrics in postoperative models.

Problem: Extent of resection (EOR) predicts survival in diffuse high-grade glioma but is only measurable postoperatively, limiting preoperative decision-making.

Approach: Preoperative whole-brain tractography (WBT) was used to quantify tumor overlap with eloquent tracts and deep structures to estimate resectability before surgery.

Metrics: Unresectable tumor volume (UTV) = tumor overlap with eloquent tracts + deep structures; Resectability index (RI) = (preop tumor volume − UTV) / preop tumor volume.

Modified metrics: mUTV/mRI focused only on corticospinal tract and left arcuate fasciculus, and performed better than unmodified metrics in several analyses.

Surgical decision prediction: mRI (AUROC 0.953) and mUTV (AUROC 0.854) accurately predicted biopsy vs resection, with optimal cutoffs mRI 0.75 and mUTV 2.5 cm³.

Survival separation: Tumors with mRI > 0.65 vs ≤ 0.65 showed the largest median overall survival difference (not reached vs 82 days, P < .0001).

Best preop survival model: A log-logistic accelerated failure time (AFT) model using only preoperative covariates achieved validated C-index 0.788, with mUTV an independent predictor of overall survival (P = .008).

Overall conclusion: Preoperative WBT-based resectability metrics approximate postoperative EOR/residual tumor volume and can strongly predict survival outcomes after biopsy or resection.

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5-Aminolevulinic Acid Fluorescence-Guided Resection of 18F-FET-PET Positive Tumor Beyond Gadolinium Enhancing Tumor Improves Survival in Glioblastoma

Neurosurgery 85:E1020–E1029, 2019

The value of early postoperative 18F-FET-PET in patients with glioblastoma (GBM) is unclear. Five-aminolevulinic acid (5-ALA) is used for fluorescence-guided resections in these patients and previous data suggest that fluorescence and 18F-FET-PET both demarcate larger tumor volumes than gadolinium enhanced magnet resonance imaging (MRI).

OBJECTIVE: To correlate fluorescence with enhancing volumes on postoperative MRI and 18F-FET-PET tumor volumes, and determine the value of postoperative 18F-FET-PET for predicting survival through observational study.

METHODS: GBM patients underwent fluorescence-guided resection after administration of 5-ALA followed by early postoperative MRI and 18F-FET-PET for determination of residual tissue volumes. All patients were treated with standard temozolomide radiochemotherapy and monitored for progression-free and overall survival (PFS, OS).

RESULTS: A total of 31 patients were included. For functional reasons, residual 5-ALA derived fluorescent tissue was left unresected in 18 patients with a median 18F-FETPET volume of 17.82 cm3 (interquartile range 6.50-29.19). In patients without residual fluorescence, median 18F-FET-PET volume was 1.20 cm3 (interquartile range 0.87-5.50) and complete resection of gadolinium enhancing tumor was observed in 100% of patients. A 18F-FET-PET volume of above 4.3 cm3 was associated with worse OS (logrank P-value≤.05), also in patients with no residual contrast enhancing tumor on MRI. More patients in whom fluorescencing tissue had been removed completely had postoperative 18F-FET-PET tumor volumes below 4.3 cm3.

CONCLUSION: Postoperative 18F-FET-PET volumes predict OS and PFS. Resection of 5-ALA derived fluorescence beyond gadolinium enhancing tumor tissue leads to lower postoperative 18F-FET-PET tumor volumes and improved OS and PFS without additional deficits.

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