[Acceptable definition of peripheral early lung cancer]

This study was conducted to evaluate the outcome of 88 patients who underwent surgical resection for peripheral non-small cell lung cancers less than 20 mm in diameter. Twenty-one cases with lesions smaller than 10 mm had no lymph node metastasis, intrapulmonary metastasis, pleural dissemination, or distant metastasis. The 5-year survival rate of them was 100%. However, 67 patients with tumors larger than 10 mm showed lymph node metastasis in 14 cases, intrapulmonary metastasis in 3, pleural dissemination in 2 and distant metastasis in 1. And the 5-year survival rates of patients with tumor dimensions of < or = 15 mm and < or = 20 mm were 77.9% and 74.4%, respectively. In addition, patients having adenocarcinoma categorized A and B by Noguchi's classification had no lymph node metastasis, intrapulmonary metastasis, pleural dissemination, or distant metastasis, and showed 100% of 5-year survival rate. To be defined as early cancers in terms of curability, it is thought that the 5-year survival rate of the patients with them is over 95%. Therefore, these results suggest that tumors smaller than 10 mm or adenocarcinoma less than 20 mm in diameter diagnosed as Noguchi's A and B are considered as peripheral early lung cancers.