Objective: Among the TNM criteria, tumor size is a well-assessed factor in the prognosis of small tumors. A 3-cm cutoff point separates T1 from T2 tumors, whereas a size larger than 3 cm is not ascribed any prognostic value. Instead, N2 is considered to be the worst prognostic factor for intrathoracic extended disease. Method: The prognosis of 545 patients with non-small cell lung cancer larger than 3 cm in diameter (T2, T3, and T4) was studied. These tumors were completely resected by pneumonectomy (n = 126) or lobectomy (n = 411) or were partially resected (n = 8). Survivals were compared according to the following factors: tumor size (3.1-5 cm, 5.1-7 cm, >7 cm), nodal status, age, sex, histologic type, degree of pleural involvement, operative procedure, stage, and T factor. For the multivariate analysis, the Cox proportional hazard model was used with the same variables. Results: The univariate analysis showed that age, sex, degree of pleural involvement, operative procedure, tumor size, nodal status, and stage were all significant prognostic factors. Further comparison of survival between different tumor sizes (≤5 cm vs >5 cm) in the same nodal category demonstrated a significantly poor prognosis for larger tumors in NO (P = .00374) and N2+N3 (P = .0157), but not in N1 (P = .3452). T2 tumors (n = 349) were divided, according to size, into T2a (n = 238) and T2b (n = 111), and survival was compared with those in T3 and T4. The 5-year survivals were 51.3%, 35.1%, 47.8%, and 25.3%, respectively. The difference between T2a and T2b was statistically significant (log-rank P = .0170, Breslow P = .0055). Conclusions: A tumor size of more than 5 cm in diameter was indicative of a poor prognosis in non-small cell lung cancer, because patients with T2b tumors had a significantly different survival from that of patients with T2a tumors, and the survival curve was located between those for patients with T3 and T4 tumors. Consequently, T2b might be upgraded to at least T3.
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