ESTRO 2024 - Abstract Book

S5053

Physics - Radiomics, functional and biological imaging and outcome prediction

ESTRO 2024

Figure 1. Plots of the multivariable model of oesophageal toxicity risk with and without concurrent chemotherapy. The orange and light blue lines describe dose-response curves with and without chemotherapy and the red dashed line indicates the 20% toxicity level. The dots represent the toxicity rates in each study (labelled), with the size of the dots proportional to the number of patients in the study. Vertical bars show 68% binomial confidence intervals, and horizontal bars represent ranges of doses. Percentages of patients receiving concurrent chemotherapy in the various studies are represented on a blue/red scale, red indicating a 100% rate and blue 0%. Due to overlapping data points, the scatter plot has been jittered.

Conclusion:

The model prediction of a 5% toxicity rate for 94.2Gy EQD2 without chemotherapy is in the range of the suggested consensus dose constraints (75 – 110Gy EQD2). CIs are wide and further data is required to validate these predictions. Chemotherapy given concurrently with re-irradation has a significant and large radiosensitising effect, a 5% modelled risk of G3 re-irradiation toxicity occurring at approximately 50Gy lower dose than in the absence of chemotherapy. This data could be used to counsel patients of the predicted risk of toxicity prior to re-irradiation.

Keywords: Re-irradiation, lung cancer, oesophageal toxicity