Lymph node status (node-positive / node-negative)
Whether the cancer has reached the nearby lymph nodes, the filters along the lymphatic drainage. It is the single strongest predictor of whether cancer has escaped the organ, and it drives most decisions about extra treatment after surgery.
The N in TNM staging counts involved regional nodes (N0 none, N1-N3 increasing). Node-positive breast cancer earns chemotherapy or CDK4/6 inhibitors (monarchE); node-positive colon cancer (stage III) gets adjuvant FOLFOX; N2 lung cancer changes surgery to chemoradiation. Nodes are assessed by imaging, sentinel node biopsy or dissection, and pathologists count how many of how many examined were positive, which is why a minimum node harvest is a surgical quality marker. Nodal micrometastases and isolated tumour cells are graded separately.