Microvascular health status as a novel predictor of acute side effects after radiotherapy: a quantitative analysis across three cancer sites.

Abstract

To quantitatively assess how microvascular conditions estimated via a non-invasive method can predict acute side effects after radiotherapy in patients with breast, prostate, and head and neck cancers. We studied 314 patients, assessing their MicroVascular Health Score (MVHS) before radiotherapy using a sublingual microscope that records videos of red blood cells in microvessels, analyses the microvasculature's functional and geometric properties, and calculates the MVHS. The MVHS was incorporated into a logistic model to predict the risk of developing acute radio-induced both alone and in combination with dose. A clear quantitative association between MVHS and side effects was observed in the overall population (OR = 0.68, p = 0.001). A 1-unit decrease in MVHS was associated with a 31.9% increased risk of radiation-induced symptoms across cancer sites. In the breast subgroup, dose factors significantly affected side effect risk (OR for D200cc to the skin: 1.05 per 1 Gy; OR for D20cc: 1.14 per 1 Gy; OR for V20Gy: 1.01 per 1 cc; all p < 0.05). The D20cc model had the highest AUC (0.69), and adding MVHS further improved it to 0.76. The study strongly linked microvascular health to the risk of acute radio-induced symptoms, suggesting that this could inform predictive models and customise treatments based on patient vascular status.