N Numerical Suffix Assignment

Nodal Stations: The first station lymph nodes are the intrapulmonary, peribronchial and hilar lympn nodes, which are contained within the visceral reflections. Second station lymph nodes are those in the mediastinum and may be paraesophageal, subcarinal, paratracheal, aortic or retrotracheal. Involvement of scalene, contra-lateral or extra-thoracic nodes is considered distant metastasis.

The correct steps for evaluation of lymph node involvement are:

• History and Physical to exclude involvement of mediastinal structures
• Chest x-ray
• Chest CT scan, especially if chest x-ray is negative.
• PET scan
• Mediastinoscopy or mediastinotomy or needle aspiration or thoracotmy, appropriate to clinical situation

Question

Let me summerize the information on a hypothetical patient on the status of lymph nodes:

• No palpable cervical nodes.
• No symptoms or physical signs of involvement of mediastinum.
• Chest x-ray showing only RUL collapse.
• CAT scan showing 3 nodes of 0.5 cms in right para-tracheal position.
• PET scan uptake in the primary lesion but negative in the mediastinum.

Please assign a numerical suffix to "N": Is it N0 or N1 or N2 or N3 ?

 Answer

"NO" is the correct nodal stage in this patient . Let us briefly review nodal stations and nodal staging.

Nodal Involvement

NX

Minimal requirements to assess the regional nodes cannot be met.

NO

No demonstrable metastasis to regional lymph nodes.

N1

Metastasis to lymph nodes in the peribronchial or the ipsilateral hilar region, or both, including direct extension.

N2

Metastasis to lymph nodes in the mediastinum and subcarinal nodes.

N3

Metastais to contra-lateral mediastinal nodes or contralateral hilar lymph nodes, ipsilateral or contralateral scalene or supraclavicular lymph nodes.