Early Local Treatment Delays Multiple Metastases in Non-Small Cell Lung Cancer With Solitary Distant Metastasis: A Multicenter Retrospective Cohort Study.

Solitary distant metastasis (SDM) is a distinct oligometastatic subtype associated with a relatively favorable prognosis. This multicenter retrospective study including 139 non-small cell lung cancer (NSCLC) patients with SDM (2019-2024) was conducted to investigate prognostic factors for multiple metastases and identify the critical time window for local treatment. Statistical analyses included Cox regression, Kaplan-Meier survival analysis, and restricted mean survival time (RMST). Results showed that driver gene status, tumor staging, systemic therapy, and local treatment were significantly associated with progression-free survival (PFS). Notably, only early local treatment significantly delayed the onset of multiple metastases (hazard ratio [HR] = 0.55, 95% confidence interval [CI]: 0.30-0.99, p = 0.05), prolonging the median time to multiple metastases by nearly 14 months (36.4 vs. 22.6 months). Kaplan-Meier and RMST analyses revealed no distinct plateau phase, indicating the absence of an absolute temporal cutoff between "true oligo-metastasis" and "transitional metastasis," which suggests that SDM in advanced NSCLC is an inherently indolent disease state. Using the maximum selected rank statistics method, an optimal cutoff of 138 days was identified to distinguish early from delayed local treatment, which requires further prospective validation.