# Emerging minimally invasive laser and light-based therapies for glioblastoma: a systematic review

## TL;DR

LITT and PDT are promising minimally invasive treatments for glioblastoma, improving survival and reducing complications in specific patient groups.

## Contribution

This systematic review evaluates the safety and efficacy of LITT and PDT as minimally invasive therapies for glioblastoma.

## Key findings

- LITT improves survival in patients with small, deep-seated glioblastomas and high Karnofsky scores.
- PDT reduces postoperative edema and local recurrence when combined with gross total resection.
- Both therapies are safe but require further large-scale trials to standardize protocols and explore combinations.

## Abstract

Glioblastoma is the most common malignant brain tumor. Standard treatment involves surgical resection with radiotherapy and chemotherapy, but tumors in deep or eloquent brain regions often limit surgical options. Laser interstitial thermal therapy (LITT) and photodynamic therapy (PDT) have emerged as minimally invasive alternatives.

This systematic review followed PRISMA 2020 guidelines. Study quality was assessed using the Newcastle-Ottawa Scale, ROBINS-I, and RoB 2 tools. Data extraction included tumor characteristics, survival outcomes, quality of life, treatment response, and complications.

A total of 1,468 records were identified; after screening and eligibility assessment, 11 studies involving patients aged 16–86 were included. LITT was found to be safe and effective for recurrent glioblastoma, with 12-month survival rates up to 65%, particularly in patients with small, deep-seated tumors and high Karnofsky scores. PDT, when combined with gross total resection, reduced postoperative edema and improved survival but was associated with higher rates of distant recurrence.

LITT and PDT are promising minimally invasive strategies for glioblastoma management, each with distinct mechanisms and clinical roles. LITT is most beneficial for deep-seated, unresectable tumors and may enhance tumor immunogenicity. PDT, though limited by shallow light penetration, effectively eliminates residual tumor cells post-resection and may reduce local recurrence. However, variability in patient selection, tumor features, and treatment protocols across studies limits direct comparison. Adverse events, while generally manageable, require close monitoring. Current evidence supports the adjunctive use of both therapies, but large-scale randomized trials are needed to confirm efficacy, standardize protocols, and explore combinations with immunotherapy.

LITT and PDT are safe and effective adjunct therapies for glioblastoma patients, improving survival and reducing complications in selected patients. LITT mostly benefits patients with small, deep, or unresectable tumors, while PDT enhances outcomes when combined with gross total resection. Further large-scale trials are needed to optimize their use and refine patient selection.