[Current condition of early peripheral lung cancer and related problems]

Early peripheral lung cancer is defined as a tumor whose diameter is within 20 mm and that has not metastasized to lymph nodes. We developed thoracoscopic surgery (two windows method) in 1993. We have been conducting this thoracoscopic surgery in early peripheral lung cancers to identify possible indications as well as to clarify problems related to early peripheral lung cancer. The subjects of this study were 176 tumors, with diameters within 30 mm, including 97 lung cancers with diameters within 20 mm. Of the 97 tumors 20 mm or less in diameter, 18 were N 1 or more severe (N 1, 8 cases: N 2, 10 cases). One patient (N 2) died of bone metastasis and two patients died due to diseases other than lung cancer. Nearly 20% of the patients with tumors 20 mm or less were in the advanced stage, suggesting that mediastinal lymph node resection is necessary. Based on these results, it is advisable to define tumors with a diameter of no more than 10 mm as early peripheral lung cancer.