Telomere length of tumor tissues and survival in patients with early stage non-small cell lung cancer

Telomere shortening leads to genomic instability that drives oncogenesis through the activation of telomerase and the generation of other mutations necessary for tumor progression. This study was conducted to determine the impact of telomere shortening on the survival of patients with early stage non-small cell lung cancer (NSCLC). Relative telomere length in tumor tissues was measured by quantitative polymerase chain reaction in 164 patients with surgically resected NSCLC. The association between telomere length and overall survival (OS) and disease-free survival (DFS) was analyzed. When the patients were categorized into quartiles based on telomere length, those patients with the 1st quartile (shortest) of telomere length had a significantly worse OS and DFS compared to patients with the 2nd to the 4th quartiles of telomere length (adjusted hazard ratio for OS=2.67, 95% confidence interval=1.50-4.75, P=0.001; and adjusted hazard ratio for DFS=1.92, 95% confidence interval=1.17-3.14, P=0.01). An association between telomere length and survival outcome was more pronounced in squamous cell carcinomas than adenocarcinomas (P-value of test for homogeneity for OS and DFS=0.05 and 0.02, respectively). Telomere length of tumor tissues is an independent prognostic factor in patients with surgically resected early stage NSCLC.