Proposals regarding some deficiencies in the new international staging system for non-small cell lung cancer.

The new international staging system remains a source of some controversial issues as the survival of 716 non-small cell lung cancer patients in our series (286 in stage I, 63 in stage II, 225 in stage IIIA, 81 in stage IIIB and 61 in stage IV) is analyzed with regard to the T, N and M categories. The problems are aired and some proposals made for revising the staging system. Multivariate analysis of significant factors contributing to the prognoses of stage I patients made it clear that the most important factor was the size of the primary tumor. A significant difference in survival was found between T1N0M0 and T2N0M0 disease. Furthermore, patients having tumors larger than 5 cm in diameter showed a significantly worse prognosis than those having tumors less than 5 cm. Accordingly, stage I should be divided into stage IA (T1N0M0, tumors less than 3 cm) and stage IB (T2aN0M0, tumors less than 5 cm). Tumors greater than 5 cm should be categorized as T2b, and T2bN0M0 disease should be classified as stage II. Patients having N2 disease involving the pretracheal (#3) node had a significantly worse survival rate than those with other ipsilateral nodal involvement, so #3 nodal involvement should be categorized as N3 disease. Patients having ipsilateral intrapulmonary satellite nodules, most of which were verified by microscopic examination of the resected specimens, had a significantly better survival rate than stage IIIB patients and showed no significant difference from stage IIIA disease. Accordingly, ipsilateral intrapulmonary satellite lesions should be categorized as T3 disease.