Abstract
BACKGROUND: A substantial proportion of patients with clinical stage I non-small cell lung cancer (NSCLC) have more advanced disease on final pathologic review. We studied potentially modifiable factors that may predict pathologic upstaging. METHODS: Data of patients with clinical stage I NSCLC undergoing resection were obtained from the National Cancer Database. Univariate and multivariate analyses were performed to identify variables that predict upstaging. RESULTS: From 1998 to 2010, 55,653 patients with clinical stage I NSCLC underwent resection; of these, 9,530 (17%) had more advanced disease on final pathologic review. Of the 9,530 upstaged patients, 27% had T3 or T4 tumors, 74% had positive lymph nodes (n > 0), and 4% were found to have metastatic disease (M1). Patients with larger tumors (38 mm vs 29 mm, p < 0.001) and a delay greater than 8 weeks from diagnosis to resection were more likely to be upstaged. Upstaged patients also had more lymph nodes examined (10.9 vs 8.2, p < 0.001) and were more likely to have positive resection margins (10% vs 2%, p < 0.001). Median survival was lower in upstaged patients (39 months vs 73 months). Predictors of upstaging in multivariate regression analysis included larger tumor size, delay in resection greater 8 weeks, positive resection margins, and number of lymph nodes examined. There was a linear relationship between the number of lymph nodes examined and the odds of upstaging (1 to 3 nodes, odds ratio [OR] 2.01; >18 nodes OR 6.14). CONCLUSIONS: Pathologic upstaging is a common finding with implications for treatment and outcomes in clinical stage I NSCLC. A thorough analysis of regional lymph nodes is critical to identify patients with more advanced disease.