The Significance of Visceral Pleural Surface Invasion in 321 Cases of Non-Small Cell Lung Cancers with Pleural Retraction

In order to improve prognostic applications and treatment decisions, we report our experiences of visceral pleural surface invasion (VPSI) in non-small cell lung cancers (NSCLCs) with pleural retraction. A total of 321 NSCLCs with pleural retraction were identified by carefully inspecting surgically resected specimens. The extent of pleural invasion, including the use of elastic stain, was evaluated. Patients with and without VPSI were compared for clinicopathologic parameters and survival. VPSI was identified in 170 (53.0 %) of the stage I-III cases and 98 (43.4 %) of the patients with stage I disease. VPSI was associated with a higher frequency of tumor size greater than 3 cm, moderate/poor differentiation, vascular invasion, mediastinal lymph node metastasis, extranodal involvement, and higher TNM stages. Multivariate analysis revealed VPSI to be a significant independent predictor of unfavorable prognosis. The 5-year survival of patients with and without VPSI was 57.9 and 83.0 %, respectively (P = 0.001), and was 74.3 and 88.5 % (P = 0.005) in stages I-III and stage I disease, respectively. VPSI is an independent factor for poor prognosis in NSCLCs, regardless of lymph node status. Stage IB NSCLCs with PL1 pleural invasion are associated with a survival rate similar to that of stage IA NSCLCs and could be classified as T1 lesions. While surgical treatment is adequate in these patients, stage IB NSCLCs with VPSI have poor prognosis, and these patients should be considered for adjuvant chemotherapy.