[Clinicopathological features of peripheral small-sized (2 cm or less in diameter) non-small cell lung cancer]

Ninety-three patients with completely resected peripheral non-small cell lung cancer, clinically diagnosed 2 cm or less in diameter, were retrospectively reviewed. Their preoperative computed tomography (CT) and positron emission tomography (PET) findings, carcinoembryonic antigen (CEA) values, clinico-pathological features and postoperative outcomes were analysed. Ground-glass opacity (GGO) ratio( soft tissue density area of the tumor/maximum area of the tumor in diameter) was measured. The overall survival rate at 3 years was 93.3% and the relapse-free survival rate at 3 years was 89.4% with a median follow-up period of 38.5 months. Patients with GGO ratio 0.25 or less had no lymph node (LN) involvement nor lymph vascular invasion. Only 2 of them (8%) had vascular invasion. Fisher's exact probability test revealed CEA ≥ 5 ng/ ml as risk factor for LN involvement( p=0.0400). Multiple logistic regression analysis showed that solid adenocarcinoma and squamous cell carcinoma recurred more frequently than adenocarcinoma with GGO (p=0.0619, odds ratio 4.969, 95%CI 0.9242~37.67).