Problems related to TNM staging: Patients with stage III non-small cell lung cancer

Objective: Many reports have raised certain problems concerning the current TNM classification of lung cancer, namely that there is no sufficient difference in prognosis between patients with pathologic stage IIIA and IIIB disease. For clarifying this problem, the present study was constructed in light of T3 and T4 classifications. Methods: Among 429 patients with non-small cell lung cancer who underwent resection, those with stage IIIA (n = 73) and stage IIIB (n = 79) disease were enrolled in this study, and their prognostic factors were compared. Results: No difference in the survivals between patients with T3 and T4 disease was observed, and this seemed to affect the prognoses of patients with stage IIIA and IIIB disease. However, when those with T3 and T4 disease were classified into different groups on the basis of TNM descriptors, differences in the survivals became evident. The T3 bronchial invasion group showed a better prognosis than the T3 extrapulmonary invasion group. The T4 tracheal invasion group and T4 pulmonary metastasis group showed a significantly better prognosis than that in the T4 extrapulmonary invasion group and the T4 malignant pleural exudate group. The surgical curativity of patients with T3 disease was evaluated as curative resection or noncurative resection, and the surgical curativity of T4 was evaluated as R0 resection or R1 or R2 resection. The T3 bronchial invasion group included more curative resection cases. The T4 tracheal invasion group and T4 pulmonary metastasis group included more R0 resection cases. Furthermore, when patients with T3 to T2 bronchial invasion and patients with T4 tracheal invasion and T4 pulmonary metastasis were reclassified as having T3 disease, the survivals of the patients reclassified as having T3 and T4 disease, as well as the resultant subsets having stage IIIA and IIIB disease, were significantly different. Conclusion: Tumor status should be reviewed by taking into account the surgical curativity.