Stage III NSCLC Treatment Patterns in Spain: A Population-Based Study of the GOECP-SEOR

<b>Objective:</b> We aimed to provide real-world insights into the management of non-small cell lung cancer stage III (NSCLC-SIII) in Spain. <b>Methods:</b> The GOECP-SEOR group conducted an observational, retrospective, multicenter study in which data from patients diagnosed with NSCLC-SIII treated in Spanish radiotherapy departments (RTDs) were collected. <b>Results:</b> A total of 1505 NSCLC-SIII patients from 35 RTDs from 2018 to 2021 were recruited. A total of 871 patients (57.9%) received concurrent chemoradiotherapy (cCRT), and 390 patients (25.91%) received maintenance durvalumab. The immunotherapy (IT) was well tolerated, with Common Terminology Criteria for Adverse Events (CTCAE) Grade 0-2 toxicity observed in 85% of the patients (295 patients). The median overall survival (OS) was 26 months (95% CI 9.4-Not Reached NR). There was a statistically significant difference when patients were stratified by IT, with a median OS of 40 months (95% CI 22.1-NR) in the IT maintenance cohort compared with 19.4 months (95% CI 7.1-58.1) in the non-IT cohort. Differences were also noted in progression-free survival (PFS), with a median PFS of 20.8 months (95% CI 9.6-NR) in the IT cohort versus 8.4 months (95% CI 3.1-25.1) in the non-IT cohort. These differences remained significant according to the multivariate model (OS: HR 0.45 [95% CI 0.36-0.56], <i>p</i> < 0.001; PFS: HR 0.5 [95% CI 0.42-0.59], <i>p</i> < 0.001). <b>Conclusions:</b> The management of NSCLC-SIII patients can vary, leading to differences in treatment outcomes. The treatment of lung cancer in NSCLC-SIII patients in RTDs across Spain aligns with international guidelines and expert recommendations.