Prognostic impact of pleural invasion in 1488 patients with surgically resected non-small cell lung carcinoma.

OBJECTIVE This study aimed to verify the prognostic impact of pleural invasion according to the revised TNM classification, seventh edition. METHODS The study consisted of 1488 patients with surgically resected non-small cell carcinoma. The degree (pl0-3) and location of pleural invasion were examined using hematoxylin and eosin- and elastica van Gieson-stained slides, and outcome was compared with stratification by several clinicopathological factors. RESULTS The 5-year overall survival rates of 1008, 260, 85 and 135 patients with pl0, pl1, pl2 and pl3 tumours were 80, 60, 55 and 52%, respectively. Overall survival differed significantly between patients with pl0 tumours and those with pl1 tumours (P < 0.0001). The difference was significant for patients with 1<≤ 2 cm (P = 0.004), 2<≤ 3 cm (P = 0.003) and 3<≤ 5 cm (P = 0.02) tumours. The overall survival of pl0 patients was also significantly better in patients with adenocarcinoma (P < 0.0001) than squamous cell carcinoma (P = 0.043). The overall survival of pl0 patients was significantly better in patients without lymph node metastasis (P < 0.0001) than in those with lymph node metastasis. The 5-year overall survival rates of patients with interlobar, lateral, mediastinal and diaphragmatic pl3 tumours were 65, 51, 51 and 40%, respectively. Overall survival did not differ significantly among these four groups. CONCLUSIONS Outcome differs between patients with pl0 tumours and those with pl1-3 tumours, particularly among patients with 1<≤ 2 cm, 2 <≤ 3 cm and 3<≤ 5 cm tumours, adenocarcinoma histology and no lymph node metastasis. The location of pl3 pleural invasion did not affect outcome significantly.