[Controversies in the new TNM staging system].

The latest revision of the International System for Staging Lung Cancer was published in June 1997. We discuss the following 4 major items in the new TNM staging system. 1) The fact that stage I was divided into stage IA (T1N0M0) and IB (T2N0M0) is reasonable, as the survival prospects for the subsets differ significantly. 2) The fact that stage II was divided into stage IIA (T1N1M0) and IIB (T2N1M0) is not appropriate, However, there is no significant survival difference between the T1N1M0 subset and the T2N1M0 subset, because there are fewer T1N1M0 cases. 3) The fact that the T3N0M0 subset was shifted into stage IIB is reasonable. Patients who undergo resection of tumors invading the parietal pleura, neighboring lobe, and main bronchus within 2 cm of the carina in the T3N0M0 group have a good prognosis, but those who undergo resection of tumors invading the rib, intercostal muscle, and diaphragm in the T3N0M0 group have a poor prognosis. 4) The decision to designate satellite lesions within the lobe of the primary tumor as T4 is controversial, because it is very difficult to determine whether satellite lesions are metastases from other lesions or if they are primary synchronous neoplasms.