Analysis of Lymph Node Sampling Minimums in Early Stage Non-Small-Cell Lung Cancer

Analyze “number of nodes” as an integer-valued variable to identify possible minimum lymph node (LN) number to sample during lung cancer resection. The National Cancer Database (NCDB) queried 2004–14 for surgically treated clinical stage I/II non-small-cell lung cancer (NSCLC). Overall survival (OS) by number of LN sampled was examined for the complete dataset, by adenocarcinoma, and by degree of resection using number of sampled LN both as integer-valued (0–30 nodes) variable and collapsed into classes. A total of 102,225 patients were analyzed. Median sampled LNs were 7. Median overall survival was 59 months if no LNs were sampled (95% confidence interval [CI]: 57.0–62.4), 74.7 months for 1 sampled LN (95% CI: 69.6–78.1), 80.2 (95% CI: 74.2–85.6) for 2 sampled LN, up to 81.5 mos. for 29 sampled LN. A Cox regression model using “0 LN” as baseline level, showed association with increased overall survival starting at 1 LN (hazard ratio [HR] 0.81, 95% CI 0.76–0.87; P