Background: The purpose of this study was to evaluate patients with stage I non-small cell lung cancer (NSCLC) and tumors up to 3 cm in maximum dimension who underwent surgical resection on the revised TNM classification and to investigate the risk factors for recurrence.
Methods: Between 1994 and 2003, 713 consecutive stage I NSCLC patients with tumors up to 3 cm in maximum dimension underwent complete resection. Recurrence-free probability was estimated from the date of the primary tumor resection to the date of the first recurrence or the last follow-up using the Kaplan-Meier method.
Results: The recurrence-free probability of stage I NSCLC patients with tumors up to 3 cm in maximum dimension was 87% at 5 years. On multivariate analyses, three variables were shown to be independently significant recurrence risk factors: histologic differentiation (hazard ratio, 2.3), intratumoral vessel invasion (hazard ratio, 2.9), and visceral pleural invasion (VPI) (hazard ratio, 1.8). According to subgroup analyses combining these three risk factors, the 5-year recurrence-free probability was 94% for patients with zero or one factor (n = 492) and 71% for patients with two or three factors (n = 221), respectively (P < .001).
Conclusion: In stage I NSCLC patients with tumors up to 3 cm in maximum dimension, we identified three risk factors for recurrence that independently increase their risk of recurrence. In addition to VPI, histologic differentiation and intratumoral vessel invasion should be examined and their data collected for the next revision of the TNM staging system.