Extent of Visceral Pleural Invasion Affects Prognosis of Resected Non-small Cell Lung Cancer: A meta-analysis

Visceral pleural invasion (VPI) has been known to be an adverse prognostic factor in non-small cell lung cancer (NSCLC). However, the prognostic significance of extent of VPI (PL0, PL1 and PL2) remains controversial. We conduct a meta-analysis to summarize available evidence on this topic. PubMed, EMBASE, OVID and The Cochrane Library were searched for published studies from inception to May 9, 2016. A total of 16 studies were included in meta-analysis. Our results showed that patients with PL1 or PL2 had poorer overall survival compared with PL0 (HR = 1.555, 95% CI 1.399, 1.730; HR = 2.447, 95% CI 1.913, 3.130) and patients with PL2 had even poorer overall survival than PL1 (HR = 1.287, 95% CI 1.114, 1.487). Patients with PL1 or PL2 had lower 5-year survival rate than PL0 patients (OR = 0.515, 95% CI 0.415, 0.640; OR = 0.441, 95% CI 0.336, 0.579) and patients with PL2 had even lower 5-year survival rate than PL1 (OR = 0.706, 95% CI 0.545, 0.915). In conclusion, extent of VPI impacts the prognosis of resected NSCLC and VPI should be categorized as PL1 and PL2 in the terms of clinical practice and trials.