BACKGROUND: There is no consensus regarding whether primary tumour resection (PTR) should be performed in non-small cell lung cancer (NSCLC) patients with unexpected pleural dissemination (PD) discovered at thoracotomy. MATERIALS AND METHODS: Consecutive NSCLC patients with surgically confirmed PD were retrospectively enrolled from two high-volume centres between January 2016 and December 2023. Patients were divided into the primary tumour resection (PTR) and exploratory thoracotomy (ET) group. PTR included wedge resection, segmentectomy and lobectomy. Patients in the ET group received biopsy only. Propensity score matching (PSM) was used to reduce selection bias from confounding factors. Disease-specific survival (DSS) and progression-free survival (PFS) were analysed using the Kaplan‒Meier method, and comparisons were made using the log-rank test. Multivariate Cox regression analyses were performed to identify the independent prognostic factors. RESULTS: A total of 223 patients were identified: 167 (74.9%) in the PTR group and 56 (25.1%) in the ET group. The median follow-up time and median survival time (MST) were 39.0 months and 49.0 months, respectively. The MST for the ET and PTR groups were 44.0 and 60.0 months, respectively (HR 0.80, 95% CI 0.51-1.24
p = 0.3097). After PSM, there were no significant differences in terms of median disease-specific survival (DSS: 60.0 vs. 61.0 months, p = 0.3419) or progression-free survival (PFS: 30.0 vs. 47.0 months, p = 0.5471) between the two groups. Multivariate analysis revealed that smoking history and a tumour size ≥ 3 cm were independent risk factors for DSS and PFS, whereas targeted therapy was an independent protective factor. CONCLUSION: Our results suggest that primary tumour resection does not improve long-term survival in NSCLC patients with unexpected PD discovered at thoracotomy. It is high time to re-evaluate the value of surgery for NSCLC patients with PD and avoid overtreatment, especially in the era of targeted therapy and immunotherapy. TRIAL REGISTRATION: ClinicalTrials.gov NCT06232967 (approval date: January 31, 2024).