2414 - Induction Chemotherapy Administration Increases the Risk of Radiation Pneumonitis in Unresectable Stage III NSCLC Patients Undergoing Concurrent Chemoradiotherapy with Immunotherapy
Presenter(s)
P. Li1, X. Liang2, Y. Qin3, B. Tian1, and D. Chen4; 1Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, Shandong, China, 2Shandong Second Medical University, Weifang, Shandong, China, 3Department of Radiation Oncology, Cheeloo College of Medicine, Shandong University, Jinan, Shandong 250012, People’s Republic of China, Jinan, Shandong, China, 4Department of Radiation Oncology and Shandong Provincial Key Laboratory of Precision Oncology, Shandong Cancer Hospital and Institute, Shandong First Medical University and Shandong Academy of Medical Sciences, Jinan, China
Purpose/Objective(s): Concurrent Chemoradiotherapy (cCRT) is a crucial treatment for patients with stage III unresectable non-small cell lung cancer (NSCLC) but is associated with radiation pneumonitis (RP), especially when combined with immunotherapy (IO), which increases the risk. Induction chemotherapy (ICT) controls tumor progression but may also cause lung tissue damage, increasing the risk of RP. However, research on the risk of RP associated with ICT, cCRT, and subsequent IO consolidation remains limited. This study aims to determine whether ICT increases RP incidence in the IO era. hypothesizing that ICT, in the context of IO consolidation, is associated with a higher RP incidence following cCRT.
Materials/Methods: Retrospective data from patients with stage III unresectable NSCLC who received cCRT and IO between 2018 and 2024 were analyzed. Exclusion criteria included surgery, targeted therapy, combination IO, palliative treatment, or driver gene mutations. Patients with thoracic radiotherapy or total radiotherapy dose < 40Gy were also excluded. Patients were divided into non-ICT and ICT groups. Baseline characteristics were compared using t-tests and ?² tests. Kaplan-Meier survival curves and Cox regression analyzed RP incidence. Logistic regression assessed the time interval between ICT and cCRT, and Cox regression evaluated RP risk in subgroups based on ICT regimens. ICT is defined as chemotherapy 2 weeks prior to cCRT, and RP was assessed using Common Terminology Criteria for Adverse Events, Version 5.0.
Results: A total of 158 patients were enrolled in the study, with 55 patients in the non-ICT group. Compared with the non-ICT group, the incidence of = Grade 2 RP was higher in the ICT group (HR: 1.970, 95% CI: 1.140 - 3.390, P = 0.015), Cox regression analysis further showed that ICT group had a significantly higher risk of = Grade 2 RP (HR: 1.843, 95% CI: 1.022 - 3.2324, P = 0.042). Subgroup analysis based on ICT regimen, compared with the EP regimen (etoposide + platinum), PP regimen (pemetrexed + platinum, HR: 0.296, 95% CI: 0.097 - 0.901, P = 0.032) and DP regimen (docetaxel + platinum, HR: 0.063, 95% CI: 0.007 - 0.585, P = 0.015) were associated with a lower incidence of = Grade 2 RP. Furthermore, longer treatment intervals between ICT and radiotherapy were associated with an increased incidence of = grade 2 RP (OR: 1.500, 95% CI: 1.079 - 2.085, P = 0.016).
Conclusion: In patients with stage III NSCLC, ICT increased the incidence of = grade 2 RP following cCRT. This study suggests that greater attention should be paid to pulmonary safety when using ICT and provides valuable insights for optimizing treatment timing and patient selection. However, as a retrospective study, it is subject to selection bias and limited sample size. Nonetheless, these findings will provide valuable insights for the design of future RCTs.