The absence of lymph nodes removed (pNx status) impacts survival in patients with lung cancer treated surgically

Objectives: We aimed to study the clinical significance of the lack of lymph node assessment (pNx status) and its impact on survival in non-small-cell lung cancer patients.Methods: We retrospectively analysed the Polish Lung Cancer Study Group database. pNx status was defined as 0 lymph nodes removed. We included 17,192 patients.Results: A total of 1080 patients (6%) had pNx status. pNx patients were more likely to be younger, be female, have a different pT distribution, have squamous cell carcinoma, undergo open thoracotomy, be operated on in non-academic hospitals, and have a lower rate of some comorbidities. pNx was more likely to be cN0 than pN1 and pN2 but less likely than pN0 (p < 0.001). pNx patients were less likely to undergo preoperative invasive mediastinal diagnostics than pN1 and pN2 patients but more likely than pN0 patients (p < 0.001). Overall, the five-year overall survival rates were 64%, 45%, 32% and 50% for pN0, pN1, pN2 and pNx, respectively. In pairwise comparisons, all pN descriptors differed significantly from each other (all p < 0.0001 but pNx vs. pN1 p = 0.016). The placement of the pNx survival curve and survival rate depended on histopathology, surgical approach and pT status. In multivariable analysis, pNx was an independent prognostic risk factor (HR = 1.37, 95%CI: 1.23-1.51, p < 0.01).Conclusion: The resection of lymph nodes in lung cancer remains a crucial step in the surgical treatment of this disease. The survival of pNx patients is similar to that of pN1 patients. pNx survival curve placement depends on the other variables which could be useful in clinical decisions.