OBJECTIVETo investigate the impact of visceral pleural invasion (VPI) on prognosis and staging in patients with stage Ib non-small cell lung cancer (NSCLC).

METHODSClinical data of 232 patients with stage Ib NSCLC surgically treated by curative resection between January 1994 and December 2003 was retrospectively reviewed. Histopathological diagnosis was reviewed by an experienced pathologist. According to the tumor size and status of VPI, patients were stratified into three group: group A: tumor > 3 cm and VPI(-); group B: tumor < or = 3 cm and VPI (+); group C: tumor > 3 cm and VPI(+). There were 45 patients in group A, 96 in group B and 91 in group C. Kaplan-Meier method was used for survival analysis. Cox proportional hazards model was used for multivariate analysis.

RESULTS187 (80.6%) patients had visceral plural invasion, while 45 (19.4%) had no. The 5-and 10-year survival rates of patients with VPI were 59.3% and 42.6%, while it was 70.1% and 56.7% for the patients without (P = 0.035), respectively. The 5-year survival rates of patients in group A, B and C were 70.1%, 61.9% and 56.2%; and 10-years survival rates were 56.7%, 50.6% and 35.9%, respectively (P = 0.018). VPI with large size of tumor was revealed by Cox multivariate analysis as an independent prognostic factor (RR = 1.530, 95% CI: 1.132-2.067, P = 0.006).

CONCLUSIONA significant difference in survival exists among the stage Ib NSCLC patients who have different T status, the patient with > 3 cm tumor and visceral plural invasion may have the worst prognosis. Further studies are still needed to assess whether it is necessary or not to modify the T2 statue of tumor > 3 cm with visceral plural invasion.