Investigations of the distant metastatic non‐small cell lung cancer without local lymph node involvement: Real world data from a large database

Abstract

IntroductionThis study aimed to investigate the presentations and survival outcomes of the distant metastatic non‐small cell lung cancer (NSCLC) without lymph node involvement to obtain a clearer picture of this special subgroup of metastatic NSCLC.MethodA least absolute shrinkage and selection operator (LASSO) penalized Cox regression analysis was used to select the prognostic variables. A nomogram and corresponding risk‐classifying systems were constructed. The C‐index and calibration curves were used to evaluate the performance of the model. Overall survival (OS) curves were plotted using the Kaplan–Meier method, and the log‐rank test was used to compare OS differences between groups. Propensity score matching (PSM) was performed to reduce bias.ResultA total of 12 610 NSCLC patients with M1 category (N0 group: 3045 cases; N1‐3 group: 9565 cases) were included. Regarding the N0 group, multivariate analysis demonstrated that age, sex, race, surgery, grade, tumor size, and M category were independent prognostic factors. A nomogram and corresponding risk‐classifying systems were formulated. Favorable validation results were obtained from the C‐index, calibration curves, and survival comparisons. Survival curves demonstrated that N0 NSCLC patients had better survival than N1‐3 NSCLC patients both before and after PSM. Furthermore, the survival of resected N0M1 patients was superior to that of those without surgery.ConclusionIn this study, a prognostic nomogram and risk‐classifying systems designed for the T1‐4N0M1 NSCLC patients showed acceptable performance. Primary lung tumor resection might be a feasible treatment for this population subset. Additionally, we proposed that lymph node stage might have a place in the forthcoming tumor‐node‐metastasis (TNM) staging proposal for NSCLC patients with M1 category.