Regional Lymph Node Classification

Metastasis to regional lymph nodes is of major importance in determining treatment and ultimately survival. Regional lymph nodes are classified as follows. N0=no lymph node metastasis; N1=metastasis to lymph nodes in the peribronchial or the ipsilateral hilar region or both, including direct extension; N2=metastasis to ipsilateral mediastinal lymph nodes and subcarinal lymph nodes, and N3=metastasis to contralateral mediastinal lymph nodes, contralateral hilar lymph nodes, ipsilateral or contralateral scalene or supraclavicular lymph nodes. 

Lymph Node Map

Fourteen numbered nodal stations are illustrated in the diagrams below. N2 nodes are numbered 1 through 9. Ipsilateral nodes are designated right or left (depending on location of primary tumor), midline prevascular and retrotracheal lymph nodes are considered ipsilateral.

Click the lymph nodes in the following diagrams:

Lymphatic Pathway of Lymph Node Spread

Buy et al defined the usual lymphatic pathways of tumor spread into the mediastinum. Abnormal mediastinal nodes were those in the lymphatic drainage territory >10 mm and the difference between this node and the largest node in the other territories was >5 mm. They reduced the number of false positives as compared to methods that used size criterion alone. [Sensitivity 78%, Specificity 99% n=97]

Buy JN, Ghossain MA, Poirson F, et al. Computed tomography of mediastinal lymph nodes in nonsmall cell lung cancer. A new approach based on the lymphatic pathway of tumor spread. J Comput Assist Tomogr 1988; 12:545-552.

This scheme can be examined in the diagram below (modified from Buy).

Axial Lymph Node Map

References

Dales RE, Stark RM, Raman S. Computed tomography to stage lung cancer. Approaching a controversy using meta-analysis. Am Rev Respir Dis 1990; 141:1096-1101. [Related Records]

Guyatt GH, Lefcoe M, Walter S, et al.Interobserver variation in the computed tomographic evaluation of mediastinal lymph node size in patients with potentially resectable lung cancer. Canadian Lung Oncology Group.Chest 1995; 107:116-119. [Related Records]

McLoud TC, Bourgouin PM, Greenberg RW, et al. Bronchogenic carcinoma: analysis of staging in the mediastinum with CT by correlative lymph node mapping and sampling. Radiology 1992; 182:319-323. [Related Records]

Mountain CF, Dresler CM. Regional lymph node classification for lung cancer staging. Chest 1997; 111:1718-1723. [Related Records]

Staples CA, Muller NL, Miller RR, Evans KG, Nelems B. Mediastinal nodes in bronchogenic carcinoma: comparison between CT and mediastinoscopy. Radiology 1988; 167:367-372. [Related Records]

Webb WR, Gatsonis C, Zerhouni EA, et al. CT and MR imaging in staging non-small cell bronchogenic carcinoma: report of the Radiologic Diagnostic Oncology Group. Radiology 1991; 178:705-713. [Related Records]

Grenier P, Dubray B. Carette MF, et al. Preoperative thoracic staging of lung cancer: CT and MR evaluation. Diag Interv Radiol 1989; 1:23-28.

Buy JN, Ghossain MA, Poirson F, et al. Computed tomography of mediastinal lymph nodes in nonsmall cell lung cancer. A new approach based on the lymphatic pathway of tumor spread. J Comput Assist Tomogr 1988; 12:545-552. [Related Records]