Prognostic significance of the extent of visceral pleural invasion in completely resected node-negative non-small cell lung cancer

Objective: Visceral pleural invasion(VPI) has been defined as invasion of the tumor beyond the elastic layer(PL1), including invasion to the visceral pleural surface(PL2). The aim of this study was to evaluate the prognostic factors and patterns of recurrence in resected node-negative nonsmall cell lung cancer(NSCLC) with VPI. Methods: We retrospectively reviewed the clinicopathologic characteristics of 355 patients with resected node-negative NSCLC with VPI at Taipei Veterans General Hospital between 1990 and 2006. The prognostic value and patterns of recurrence were analyzed and compared between PL1 and PL2 groups. Results: The median follow-up time was 54.2 months. The 5-year overall survival rate and probability of freedom from recurrence were 61.9% and 66.2%, respectively. The extent of VPI was PL1 in 300 patients (84.5%) and PL2 in 55 (15.5%). During follow-up, 107 patients (30.1%) developed recurrence. The patterns of recurrence included local recurrence only in 20 patients (18.7%), distant metastasis only in 59 (55.1%), and both local recurrence and distant metastasis in 28 (26.2%). Thirteen of the 107 patients (12.1%) with recurrence developed malignant pleural effusion. The percentage of malignant pleural effusion in the PL2 group was significantly higher than that in the PL1 group (P = .006). Patients with PL2 had significantly worse overall survival(P + .046) and lower probability of freedom from recurrence(P = .028) in multivariate analysis. Conclusions: PL2 was a significant prognostic factor for recurrence and worse overall survival in node-negative NSCLC with VPI. This information is important for further design of clinical trials for aggressive adjuvant therapy.