Objectives: The tumor size is an important prognostic factor in non-small cell lung cancer (NSCLC). However, a criterion for tumor size has remained unchanged for the last 25 years in TNM classification. The purpose of this study was to determine the relationship between tumor size and survival in patients with non-small cell lung cancer.
Method: Of 550 consecutive patients who underwent operation for NSCLC between 1994 and 1998, we reviewed the medical record of 509 patients. There were 470 men and 39 women. Survivals were compared according to groups of tumor size (Group I: < or = 3 cm, Group II: 3.1-4 cm, Group III: 4.1-5 cm, Group IV: >5 cm, Group A (II + III): 3.1-5 cm, and Group B (IV): >5 cm). The Cox proportional hazard model was used with same variables.
Results: The univariate analysis showed that poor pulmonary function test (P < 0.05), pneumonectomy (P < 0.05), limited resection (P < 0.001), tumor size larger than 5 cm (P = 0.006), T factor (P < 0.05), N status (P < 0.001), and advanced staged of disease (P < 0.001) were all significant prognostic factors. Further comparison of survival between tumor size groups demonstrated a significantly poor prognosis for larger tumors. There was a statistically significant difference between Group A (3.1-5 cm) and Group B (> 5 cm), with 5 years survivals of 45.9% and 31.4%, respectively (P = 0.005).
Conclusion: We emphasize that tumor size is an important prognostic factor in NSCLC. The 5 years survival with tumors larger than 5 cm (31.4%), is significantly less than the tumors 3.1-5 cm (45.9%) (P = 0.005). These initial results should strongly encourage additional studies in different countries on the interaction between tumor size and lung cancer characteristics to better clarity. In future revisions of the TNM classification, 5 cm may be a new threshold.