About the necessity of improving the current nodal classification of non-small cell lung carcinoma

The current classification of lymph node status in non-small cell lung carcinoma has not been revised since 1997. This fact has prompted many authors to point out the limits of this classification.

We tried to explore the prognostic relevance of the current TNM classification in comparison with the nodal classification based on the ratio of metastatic lymph nodes (LNR) and the nodal classification based on the number of metastatic LNs (nLN). Additionally, we tried to explore the recommended number of resected LNs. This was done through a retrospective study of 39 cases. We compared the survival curves of patients using the current, RLN and nLN classifications. In the nLN classification, we grouped patients into three categories: nNO (no metastatic LNs), nN1 (1 to 2 metastatic LNs) and nN2 (> 2 metastatic LN). In the LNR classification, we grouped patients into three categories: rNO (0%), rN1 (< or = 12) and rN2 (> 12). Concerning the total number of the resected LNs, patients were categorized into two groups according to the number of LNs: < 10 versus > or = 10 and < 15 versus > or = 15.

Our results showed that the LNR classification highlighted a difference in prognosis between the rN1 and rN2 groups. Moreover, survival of patients seemed to be better when the number of the resected LNs was higher.

The ratio of metastatic LNs seems to be an important prognostic factor, but further studies are necessary to standardize this classification.