Axillary dissection is not required for all patients with breast cancer and positive sentinel nodes.

Hypothesis: Sentinel node (SN) biopsy for breast cancer enhances staging sensitivity, often demonstrating only micrometastases (<2 mm) or isolated, keratin-positive cells. When SN metastasis is present, the value of additional axillary dissection is unclear and not all patients benefit from axillary lymph node dissection (ALND).

Design: Prospective cohort study, median 32-month follow-up.