Prognostic significance of visceral pleural invasion in patients with surgically resected small-cell lung cancer: a population-based study.

OBJECTIVE:Visceral pleural invasion is an adverse prognostic factor in non-small-cell lung cancer, but its value in small-cell lung cancer remains unclear. Thus, we investigated the prognostic impact of visceral pleural invasion in patients with surgically resected small-cell lung cancer. METHODS:We queried the Surveillance, Epidemiology and End Results Program database for patients diagnosed with stages I-III (excluding N3 and nodal metastasis cannot be evaluated (NX)) small-cell lung cancer from 2004 to 2016, who underwent surgery. To minimize unbalanced baseline characteristics between the visceral pleural invasion and non-visceral pleural invasion groups, one-to-one propensity score matching was employed. A Kaplan-Meier curve was used to compare the overall survival of the two cohorts. A Cox proportional hazards model was adopted to determine the impact of visceral pleural invasion on survival. RESULTS:Of the 1416 patients included, 372 (26.27%) presented with visceral pleural invasion. Patients with visceral pleural invasion showed significantly worse overall survival (P < 0.001) both before and after propensity score matching. Multivariable analysis indicated that visceral pleural invasion was an independent adverse factor affecting survival. Patients with visceral pleural invasion showed poorer overall survival (hazard ratio: 1.44; 95% confidence interval: 1.17-1.76; P < 0.001). Subgroup analyses revealed that the non-visceral pleural invasion group was associated with favourable overall survival in N0 patients (P = 0.003) but not in N1 or N2 patients (P = 0.774 and 0.248, respectively). Patients diagnosed at younger ages, females, lower N stage, resection with a lobectomy and adjuvant chemotherapy were associated with improved overall survival in the visceral pleural invasion group. CONCLUSIONS:Visceral pleural invasion was an indicator of a poor prognosis for small-cell lung cancer, especially in those with N0 disease. Adjuvant chemotherapy significantly improves patient outcomes for patients with visceral pleural invasion.