cN Classification

Field Length:  4

Clinical N identifies the absence or presence of regional lymph node metastasis and describes the extent of regional node metastases prior to the start of any therapy.

Record the clinical N value as documented by the first treating physician or the managing physician in the medical record.  If the managing physician has not recorded clinical N, registrars should code this item based on the best available information, without necessarily requiring additional contact with the physician.  

If the value is only one digit, record to the left and leave the second space blank. Choose the lower (less advanced) N category when there is any uncertainty. Refer to the AJCC Cancer Staging Manual for coding rules.

When a primary tumor directly extends into lymph nodes, code as lymph node metastasis.