Population-based incidence trends and surgery-associated survival among patients with synchronous lung metastases...

Lung metastasis (LM) imposes a substantial burden on the management of solid tumors. Although local surgical interventions remain controversial, particularly for lung-limited metastasis (LLM), pan-cancer evidence on surgery-associated survival outcomes remains limited. This study aimed to delineate the epidemiological landscape of LLM and evaluate cancer-type-specific associations between surgical interventions and overall survival using large-scale population-based data. Data were obtained from the Surveillance, Epidemiology, and End Results database (2010-2022). A total of 157,365 patients with synchronous LM were identified among 3,621,017 cases of solid tumors. Temporal trends were analyzed using a Joinpoint regression. To improve balance in measured baseline covariates and mitigate observed treatment-selection imbalance, overlap weighting based on propensity scores was employed. Kaplan-Meier and Multivariable Cox regression analyses were conducted to estimate the associations of primary tumor resection (PTR), pulmonary metastasectomy (PM), and combined surgery with overall survival (OS) across 24 primary cancer types. The absolute number of synchronous LM cases increased over time, whereas the utilization of PTR remained relatively stable. Among patients with LLM, PTR was associated with lower all-cause mortality in 16 cancer types after adjustment for measured covariates (e.g., breast and colorectal cancers; hazard ratio [HR] < 1.00, p < 0.001), whereas no statistically significant association was observed in anal, biliary, bladder and ureter, esophageal, prostate cancers, small intestine, or testis cancers (p > 0.05). PM showed consistent associations with lower all-cause mortality in 11 cancer types, including colorectal, soft tissue, and liver cancers, with HRs ranging from 0.40 to 0.77 (p < 0.05). Combined surgery (PTR plus PM) was associated with lower all-cause mortality than PTR alone in bladder and ureter, breast, colorectal, soft tissue, skin, and thyroid cancers (HR range, 0.52-0.80; p < 0.05). Collectively, the overall disease burden of LM remains substantial, with highly heterogeneous underlying drivers. In patients with LLM, surgery-associated survival patterns varied markedly by cancer type, supporting cancer-type-specific evaluation of PTR and PM within multidisciplinary decision-making. These population-based findings warrant prospective validation and should be interpreted in light of residual confounding and treatment selection bias.