Background and Objectives: Consolidation durvalumab after chemoradiotherapy (CRT) is the standard of care for unresectable stage III non-small cell lung cancer (NSCLC). However, a substantial proportion of patients do not receive this treatment in real-world practice.. This study aimed to evaluate the efficacy of post-progression immune checkpoint inhibitor (ICI) therapy in patients with stage III NSCLC who did not receive durvalumab consolidation. Materials and Methods: This multicenter retrospective study included 403 patients with stage III NSCLC who received definitive CRT without durvalumab consolidation between January 2010 and December 2025. Patients were divided into ICI group (n=61) and non-ICI group (n=338) based on post-progression treatment. All patients has ECOG PS 0-1 The primary endpoint was overall survival (OS), analyzed using Kaplan-Meier and multivariate Cox regression methods. Early progression was defined as recurrence within 6 months after CRT completion. Results: The median OS was significantly longer in the ICI group compared to the non-ICI group (47.97 months [95% CI: 35.68–60.26] vs. 19.29 months [95% CI: 17.88–20.69]; p<0.001), representing a 2.5-fold survival advantage. Patients with early progression had a significantly worse prognosis compared to those with late progression (median OS: 7.06 vs. 20.01 months; p<0.001). In the ICI group, PD-L1-positive patients had numerically longer median OS than PD-L1-negative patients (54.05 vs. 46.03 months). Multivariate analysis identified post-progression ICI use (HR: 0.37, 95% CI: 0.25–0.54; p<0.001) and early progression (HR: 2.61, 95% CI: 1.91–3.57; p<0.001) as independent prognostic factors. Conclusions: Post-progression immunotherapy was associated witha significant survival benefit in patients with stage III NSCLC who did not receive durvalumab consolidation, with a median OS approaching 48 months. Early progression within 6 months after CRT is the strongest negative prognostic factor. These findings suggest that immunotherapy should be considered in this frequently encountered patient population, provided performance status is adequate. Prospective validation is needed.

Background: Cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) combined with endocrine therapy represent the gold standard in the first-line treatment of hormone receptor (HR)-positive, HER2-negative metastatic breast cancer (MBC). However, the optimal timing of CDK4/6i initiation in patients with bone-only disease (BoD) remains a matter of clinical discussion. This multicenter retrospective study evaluated the impact of CDK4/6i treatment line (first-line vs. second-or-later-line) on progression-free survival (PFS) and overall survival (OS) in HR+/HER2− MBC patients with BoD. Methods: A total of 282 HR+/HER2− MBC patients with radiologically confirmed BoD treated across five tertiary academic centers were analyzed. All patients received bone-modifying agents (zoledronic acid or denosumab). Patients were categorized into Group 1 (first-line CDK4/6i, n = 193) and Group 2 (second-or-later-line CDK4/6i, n = 89). Baseline characteristics were recorded. Multivariable Cox proportional hazards models were adjusted for key clinicopathological variables. Results: The median PFS was 30.193 months in the first-line group and 19.253 months in the second/later-line group, with no statistically significant difference (p = 0.055). The median OS was 62.324 months in the first-line group and 72.00 months in the second/later-line group, which was significant in the univariate analysis (p = 0.036). However, this significance was not maintained in the multivariate analysis adjusting for potential confounders (p = 0.487). Except for strong ER positivity, baseline characteristics were balanced between groups. In the multivariate analysis, no clinical factor, including treatment line, independently and significantly impacted OS. Conclusions: In HR+/HER2− MBC patients with bone-only disease, first-line CDK4/6 inhibitor therapy demonstrates a trend toward superior PFS. After correcting for key observational biases, the later line of therapy does not independently alter OS. These findings reinforce that first-line CDK4/6 inhibitor plus endocrine therapy remains the definitive standard of care, and later-line initiation should be reserved solely for select clinical scenarios where first-line use was not feasible.