Induction immunochemotherapy followed by definitive chemoradiotherapy and consolidation immunotherapy for unresectable stage Ⅲ non-small cell lung cancer: a multi-institutional retrospective cohort study

Zhixue Fu^1,2Xin Dong¹Jiawen Sun¹Weihu Wang^1*Wei Deng¹Yuting Zhao¹Dan Yang¹Leilei Jiang¹Xiao Chang¹Rong Yu¹ANHUI SHI¹Huiming Yu¹Jidong Wang²Wei Jiang³Jiawei Lu³Dongjie Chen³Jun Liang^3*

• ¹Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Department of Radiation Oncology, Peking University Cancer Hospital and Institute, Beijing, China
• ²International Hospital, Peking University, Beijing, Beijing Municipality, China
• ³National Cancer Center, Cancer Hospital Shenzhen Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Shenzhen, China

Background: For unresectable stage Ⅲ non-small cell lung cancer (NSCLC), the standard regimen is definitive concurrent chemoradiotherapy (CRT) followed by consolidation immunotherapy. We investigated whether incorporating induction immunochemotherapy enhances the efficacy. Materials and methods: From June 2018 to December 2022, 294 patients with unresectable stage Ⅲ NSCLC were included, who did (162, I-CRT-I group) or did not (132, CRT-I group) receive induction immunochemotherapy, followed by definitive CRT and consolidation immunotherapy. Propensity score matching (PSM) adjusted for potential confounding variables. Overall survival (OS), progression-free survival (PFS), recurrence pattern, and safety were evaluated. Results: After PSM, 206 patients (103 in each group) were included. The median follow-up time was 32.3 and 44.6 months for the I-CRT-I and CRT-I group, respectively. The I-CRT-I group showed a significant improvement in OS compared with the CRT-I group (p=0.004). The median OS in the I-CRT-I group was not reached, with 1-, 2-, and 3-year OS rates of 91.3%, 80.0%, and 72.9%, respectively; the CRT-I group had a median OS of 39.3 months, with survival rates of 91.1%, 69.3%, and 52.0%, respectively. PFS (p=0.332) and local locoregional recurrence (p=0.940) were not significantly different between the groups, while significantly lower cumulative distant metastasis (DM) was noted for the I-CRT-I group (p=0.004). Prior to PSM, the adverse events rate was 96.3% and 95.5% in the I-CRT-I and CRT-I groups, respectively, with pneumonitis noted in 57.4% and 58.3%, respectively. Conclusion: Induction immunochemotherapy followed by definitive CRT and consolidation immunotherapy may improve OS and decrease DM, along with manageable safety.