The seventh edition of TNM classification for non-small cell lung cancer (NSCLC) has been approved. Vascular invasion has been reported as being a strong risk factor; therefore, we reviewed the impact of vascular invasion on new TNM classification.
We reviewed patients with completely resected NSCLC without lymph node metastasis treated at our institute between January 1993 and December 2003. Vascular invasion was examined using Victoria blue-van Gieson stains performed in maximum cut sections of tumor. Correlation between vascular invasion and other clinicopathologic factors, such as age, sex, histology, serum carcinoembryonic antigen (CEA) levels, smoking habitation, and T descriptors, were assessed. In addition, we evaluated the impact of vascular invasion on survival.
A total of 826 patients were analyzed. Median age was 65 years (range, 32-86). Thirty-two percent of patients were > 70 years, 44% were women, 78% had adenocarcinoma, 41% were never smokers, 39% smoked > 30 pack-years, and 31% had elevated serum CEA levels. Vascular invasion was detected in 279 patients (33.8%) and more was observed in patients who were male, did not have adenocarcinoma, were smokers, and had elevated CEA levels. Positive vascular invasion was significantly correlated with worse prognosis compared with negative (5-year survival, 90.5% vs 71.0%, P < .001). This trend was observed in each subgroup of T1a (92.9% vs 72.5%, P < .001), T1b (89.7% vs 77.2%, P = .015), and T2a (86.3% vs 65.6%, P < .001).
Vascular invasion was a strong prognostic factor in the revised TNM classification. Further investigation is warranted to generalize these findings.