Assessment of adequacy of intraoperative nodal staging and factors influencing the lack of its compliance with recommendations in the surgical treatment of non-small cell lung cancer (NSCLC).

Background: Adequate pathological status of lymph nodes sampled during resection of NSCLC determines prognosis and decides on further therapeutic actions. The areas of analysis are the factors affecting evaluation of pN accuracy, and the convergence of recommendations with actual intraoperative sampling of lymph nodes.

Methods: The data of 3,215 patients with NSCLC consecutively operated with the intention of radical resection in 2007-2017, were analyzed. Accuracy of nodal sampling and influencing factors were compared with Union for International Cancer Control (UICC) guidelines, which recommend that to confirm pN0 status at least six lymph nodes/stations free of the disease must be removed. Three should be sampled from mediastinum (including subcarinal) and three from N1 stations.

Results: A significant number of patients were found to have an adequate staging, especially after 2009, in terms of recommended quantity of nodes/nodal stations (P<0.0001). Age ≥64 (P=0.048), left side (P<0.0001), sublobar resection (P<0.0001), T1 tumors (P=0.019) are the factors affecting inadequacy of staging. Patients with inaccurate staging were found to have a considerably lower pN1 (7.2% 15.9%, P<0.001) and pN2 (9.7% 13.4%, P<0.001) status. Survival of patients with inadequate staging were found to be significantly worse (P=0.0002), which resulted in worse survival of those patients in stage I (P=0.00004), stage II (P=0.023) and stage III (P=0.031) of NSCLC.

Conclusions: UICC recommendations led to an increased adequacy of nodal sampling. The factors affecting insufficient number of sampled nodes include advanced age, left side, sublobar resections and T1 stage. Inaccuracy of intraoperative nodal staging results in incorrect prognosis.