ESTRO 2022 - Abstract Book

S939

Abstract book

ESTRO 2022

Results 30.6% of patients failed the water test at 1 year. Water test at baseline, HPV status (assessed via P16), and performance status (PS) were selected for the final model (table 1 and figure 1). Performance of the model, assessed via AUC and adjusted for optimism, was 0.76. The strongest predictor for failing water test at 1 year is the test at base line (OR 6.8, p<0.001). Additionally, HPV negative patients have approximately 3 times the chance of failing the test at 1 year (OR 2.9, p=0.04), indicating possible differences in treatment toxicity trajectory. Conversely, poorer general status (PS 1+ vs PS 0) is also associated with a higher risk of failing the test (OR 2.18, p=0.09).