ESTRO 2024 - Abstract Book

S5413

Radiobiology - Tumour biology

ESTRO 2024

2471

Digital Poster

Microbeam radiation therapy for lung cancer treatment: a systematic review of the literature

Abbie Reynolds, Laure H Marignol

Trinity St. James’s Cancer Institute, Radiobiology and Molecular oncology Research group, Applied Radiation Therapy Trinity, Radiation Therapy, Dublin, Ireland

Purpose/Objective:

Microbeam radiation therapy is a preclinical spatially fractionated dose delivery technique consisting of micrometre wide beamlets, producing high peak-dose regions separated by low-dose valley regions. This novel radiation therapy technique has the potential to minimise dose-limiting radiation-induced lung toxicities and provide excellent local control rates for lung cancer treatment. Lung cancer is the leading cause of cancer-related death, and although advanced radiation therapy techniques such as stereotactic ablative radiation therapy exist, avoiding radiation induced toxicities including lung fibrosis remains challenging. Microbeam radiation therapy has unique characteristics that can significantly reduce normal tissue toxicity without compromising local control, improving the therapeutic window for lung cancer treatment. This systematic review aimed to examine the reported beam arrangements, dosimetry parameters, toxicities, and toxicity assessment methods of microbeam radiation therapy in lung cancer preclinical studies.

Material/Methods:

PubMed, Embase, Science Direct, and Web of Science were searched using the following keywords, ‘microbeam’, ‘micro beam’, and ‘lung’ to identify studies that investigated the effects of microbeam radiation therapy on the lung.

Results:

Twenty-seven studies were assessed. Studies consisted of a single microbeam, an array of microbeams, and multiple arrays of microbeams. The microbeam widths ranged from 2µm to 630µm, and the microbeam spacing ranged from 0µm to 4000µm. The most common microbeam width and microbeam spacing combination was a beam width of 50µm and beam spacing of 400µm. The peak doses ranged up to 1000Gy and dose rates ranged from <0.2Gy/s to 1.4x104 Gy/s, although the majority of studies did not report the dose rate. Fibrosis was the most commonly assessed radiation-induced toxicity, and the Hübner grading scheme was used to quantify lung fibrosis in two studies. The assessment of radiation-induced toxicities included histological analysis and imaging.

Conclusion: