ESTRO 2024 - Abstract Book

S5007

Physics - Radiomics, functional and biological imaging and outcome prediction

ESTRO 2024

Results:

Fifty-five patients out of 161 (34%) developed grade 4 RIL (G4RIL) during RT treatment. Median ALC value at nadir during RT and median ALC value at baseline (RT start) were 0.26*109 cells/l ([0.04-0.88]*109 cells/l) and 1.78*109 cells/l ([0.30-4.00]*109 cells/l), respectively. Median patients age was 66 years ([33-85] years). After the variable selection procedure, multivariable modeling resulted in a model with two predictors. They included ALC value at baseline (model coefficient- β1 = (-0.63 ± 0.27) *10-9 cells/l) and the relative volume of healthy lungs receiving at least 5 Gy (V5Gy) (β2 = 4.37 ± 1.35) The training AUC was 0.72 (95% CI [0.63-0.80]) and LOO cross validation AUC was 0.68 (95% CI [0.59-0.76]). AUC values and calibration plots (Figure) confirmed good prediction and calibration performances.

Figure . Training (a) and cross-validation (b) ROC curves; training (c) and cross-validation (d) calibration plots of the multivariable logistic regression NTCP model for severe RIL. In c) and d), the error bars for the reported values represent the 68% confidence intervals

Conclusion: