ESTRO 2022 - Abstract Book

S1055

Abstract book

ESTRO 2022

Acute esophagitis (AE) is associated with discomfort and may lead to treatment interruption. The goal of this work was to explore published AE models in an independent thoracic cancer cohort treated with hypofractionated radiotherapy (RT) and define dose-volume histogram (DVH) thresholds associated with high AE risk in order to identify patients for more intensive monitoring and symptom management. Materials and Methods PubMed was searched for published models relating to ≥ grade 2 AE (AE2+). Models were explored in 138 internally accumulated thoracic patients that received RT alone in 15 fractions (3Gy or 4Gy/fraction) between January 2019 and March 2021 after correcting the esophagus doses for fractionation effects (using a/b=10Gy). The AE2+ rate was 19%. Calibration and discrimination of the published models was assessed (Hosmer-Lemeshow p-value (pHL) and AUC), and the DVH threshold was defined at the dose level prior to the steepest part of the dose-response curve and at which the first AE2+ case was observed. Results One mean dose model and one D3 cm 3 model were identified. Both models correctly distinguished AE2+ with high reliability (Mean dose, D3 cm 3 models: AUC=0.89, 0.85), but only the D3 cm 3 model was well calibrated to data (pHL=0.26; Figure 1), and yielded a much steeper dose-response curve. The associated DVH threshold was 26 Gy in EQD2 a/b=10Gy and was located at a predicted AE2+ rate of 9.8%. This DVH threshold has been internally incorporated as an action level for recruitment to the AE intervention program for all patients receiving thoracic RT in 15 fractions. During the first month of roll out, 5 patients have been identified for high risk of AE (median fractionation-corrected D3 cm 3 : 49 Gy) and thus enrolled for further intervention. Of these, four patients have developed AE2+.

Conclusion We present results on the validation of published models to be used directly in clinical decision-making to reduce the rate of AE2+, improve overall outcomes, care and cost effectiveness of hypofractionated thoracic RT. So far, four of the five patients that were indicated by the developed D3 cm 3 action level and recruited to the intervention program, have developed AE2+.

PO-1251 Perceived-health status in lung cancer survivors presenting long-term radiotherapy-related fatigue.

P. Blasco Valls 1 , V.C. Hernández Uribe 1 , A. Heredia Ciuró 2 , L. López López 2 , M. Granados Santiago 3 , M.C. Valenza 2

1 Hospital Universitario Clínico San Cecilio, Radiation Oncology, Granada, Spain; 2 Universidad de Granada, Physical Therapy, Granada, Spain; 3 Universidad de Granada, Nursing, Granada, Spain Purpose or Objective Radiotherapy-related fatigue is a common early and chronic side-effect of irradiation, reported in up to 80 and 30% of patients during radiation therapy and at follow-up visits. Different studies have been proved that fatigue is related to perceived-health status. However, more studies in lung cancer are needed. The aim of this study was to evaluate the perceived-health status of lung cancer survivor that experienced radiotherapy-related fatigue in a long way. Materials and Methods In this observational study, lung cancer survivors with different stages treated with radiotherapy were included. These patients were evaluated one year after radiotherapy treatment. They were classified in two groups according to the fatigue levels that was evaluated by the Fatigue Severity Scale (Severe Fatigue > 42). Perceived-health status was evaluated by the EuroQol-5D questionnaire (EQ-5D).