2024 Asia Conference on Lung Cancer (ACLC) - Poster & ePosters-EP02.09

EP02.09 - Kang Wang

Pdf Summary

This study explores dose-volume constraints for lung tissue in patients with non-small-cell lung cancer (NSCLC) undergoing thoracic radiotherapy (TRT) after immune checkpoint inhibitor (ICI) treatment. The aim is to identify risk factors for symptomatic radiation pneumonitis (RP) and establish safe dosing guidelines.<br /><br />The research examined patients who received TRT following ICIs from 2021 to 2023, focusing on symptomatic RP occurrence, assessed using the Common Terminology Criteria for Adverse Events version 5.0. The link between clinical and lung dosimetric parameters, such as mean lung dose (MLD) and volume percentages (V10, V20, V30, V40), was studied to determine their impact on symptomatic RP. Receiver operating characteristic (ROC) curves helped identify threshold values for predicting RP.<br /><br />Results showed that 48.3% of patients developed RP, with 25.4% experiencing symptomatic (Grade 2 or higher) RP. No Grade 4–5 RP cases were observed. The onset of symptomatic RP typically occurred within approximately 83.5 days post-radiotherapy. Combining risk factors offered better predictive capacity than using dosimetric or clinical factors alone. Identified optimal dose thresholds were MLD of 9.7 Gy, V10 at 26.3%, V20 at 15.9%, V30 at 13.3%, and V40 at 8.6%. Staying below these levels correlated with a lower symptomatic RP incidence of 12%.<br /><br />Independent risk factors for symptomatic RP included tumor location, timing between immunotherapy and radiotherapy, and specific dose-volume parameters. The study emphasizes recommendations to lower current dose thresholds to minimize RP risk for patients undergoing ICI-TRT.<br /><br />This research was funded and supported by various Chinese scientific and medical foundations and underscores the crucial role of careful radiotherapy planning in minimizing adverse effects.

Keywords

dose-volume constraints

non-small-cell lung cancer

thoracic radiotherapy

immune checkpoint inhibitor

symptomatic radiation pneumonitis

mean lung dose

volume percentages

risk factors

predictive capacity

radiotherapy planning