Impact of adjuvant immunotherapy after pathologic complete response to neoadjuvant chemo-immunotherapy in resected stage II–III non–small cell lung cancer.

8062 Background: Perioperative chemo-immunotherapy has recently emerged as a new standard of care for patients with resectable non–small cell lung cancer (NSCLC) following positive results from the CheckMate-77T (NCT04025879) and KEYNOTE-671 (NCT03425643) trials. However, whether patients who achieve a complete pathologic response (pCR) after neoadjuvant chemo-immunotherapy derive additional benefit from subsequent adjuvant immunotherapy remains uncertain due to limited available data (only 58 patients achieved pCR in CheckMate-77T and 72 patients in KEYNOTE-671). The INSIGHT clinical trial (NCT06498635) is an ongoing phase III study designed to address this question; however, the trial is expected to be completed in 2039. Therefore, generating additional data in this area is critically important. We performed a retrospective analysis to assess whether the addition of adjuvant immunotherapy improves overall survival (OS) among patients with stage II–III NSCLC who achieve pCR following neoadjuvant chemo-immunotherapy. Methods: We conducted a retrospective cohort study using the National Cancer Database (NCDB) and included patients with complete follow-up data who were diagnosed between 2018 and 2023 with clinically staged IIA–IIIB NSCLC (cT1–cT4, cN0–cN2, cM0), underwent definitive surgical resection with pCR (ypT0N0M0), and received either neoadjuvant chemo-immunotherapy alone or neoadjuvant chemo-immunotherapy followed by adjuvant immunotherapy (perioperative chemo-immunotherapy). Survival outcomes were analyzed using Kaplan–Meier methods. Results: A total of 1,816 patients were included, of whom 967 (53.2%) were male, with a median age of 65 years (IQR, 60–71). Among these patients, 1,186 (65.3%) received neoadjuvant chemo-immunotherapy alone, and 630 (34.7%) received perioperative therapy. No significant difference in overall survival was observed between the two treatment groups. Median OS was not reached in either group, with a hazard ratio of 1.235 (95% CI, 0.602–2.533; p = 0.565). Conclusions: Among patients with stage II–III NSCLC who achieve pCR following neoadjuvant chemo-immunotherapy and undergo surgical resection, we observed no significant difference in overall survival between those treated with neoadjuvant therapy alone versus perioperative chemo-immunotherapy. These findings suggest that neoadjuvant chemo-immunotherapy alone may be sufficient for patients who achieve pCR, and that adjuvant immunotherapy in this setting may not provide additional survival benefit.