A 55-year-old postmenopausal woman is found to have a 1.8 cm invasive lobular carcinoma of the breast, ER+/PR+/HER2-. She undergoes wide local excision with sentinel lymph node biopsy; 2 of 4 nodes show isolated tumour cells (ITC) only. According to the current AJCC 8th edition breast cancer staging, what is her pathological N stage?
- A pN1mi
- B pN0(i+) ✓
- C pN1a
- D pN0
Correct answer: B. pN0(i+)
Explanation
In AJCC 8th edition, isolated tumour cells (clusters ≤0.2 mm or <200 cells) are classified as pN0(i+), meaning they do not qualify as micrometastases or macrometastases and do not upstage the nodal category. pN1mi requires tumour deposits >0.2 mm but ≤2 mm; pN1a indicates 1–3 positive axillary nodes with metastases >2 mm. The clinical significance is that pN0(i+) patients are generally managed like node-negative patients regarding axillary dissection decisions.
Reference: Bailey & Love's Short Practice of Surgery, 27th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.