Abstract
BACKGROUND: The predictive and prognostic impact of factors associated with visceral pleural invasion (VPI) on survival and recurrence in patients with resected lung adenocarcinomas is not clearly defined. PATIENTS AND METHODS: A total of 505 consecutive patients with stage Ia-IIIa lung adenocarcinomas treated with radical resection were included. The predominant growth pattern was classified according to the new classification system for lung adenocarcinoma proposed by the International Association for the Study of Lung Cancer, the American Thoracic Society, and the European Respiratory Society. The correlations of VPI with clinical and pathologic parameters were analyzed. RESULTS: The incidence of VPI was significantly lower in lepidic predominant group (15.5% vs 4.5%, P<0.001) and higher in solid and micropapillary predominant group (28.6% vs 17.6%, P=0.004 and 14.7% vs 4.2%, P<0.001, respectively). VPI correlated with higher risk in regional postoperative recurrence (hazard ratio, 2.341; 95% confidence interval, 1.564-3.504) and distant recurrence (hazard ratio, 2.193; 95% confidence interval, 1.665-2.89) in surgically resected lung adenocarcinomas. However, when growth patterns of adenocarcinoma were lumped into multivariate analysis, VPI was not a significant independent predictive factor for survival (P=0.854 for overall survival [OS] and P=0.575 for disease-free survival [DFS]) and recurrence (P=0.38 for regional recurrence and P=0.089 for distant recurrence). Of the 95 patients with stage Ib, those who received adjuvant chemotherapy had longer DFS and OS than the patients who received no chemotherapy after surgery. However, these differences in DFS and OS did not reach statistical significance (P=0.063 for DFS, P=0.85 for OS). CONCLUSION: VPI was associated with solid and micropapillary histology. In addition, stage Ib patients with solid histologic subtype tumor showed longer DFS and OS, highlighting a potential benefit in this subgroup of patients and necessitating the need for larger clinical trials.