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

Introduction: This 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.

Method: A 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.