Lymph Node Surgery for Breast Cancer

When breast cancer is diagnosed, one of the most important questions your surgical team needs to answer is whether the cancer has spread beyond the breast to the lymph nodes in the armpit. The answer to this question has a direct and significant influence on staging, prognosis, and treatment planning.

The lymph nodes in the axilla (armpit) are the primary regional drainage site for breast tissue. If cancer cells escape the primary tumour and travel through the lymphatic system, the axillary lymph nodes are the first place they are likely to accumulate. Assessing and, where necessary, treating these nodes is an essential component of breast cancer surgery for most patients.

Lymph node surgery for breast cancer encompasses three related but distinct procedures, each with specific indications and clinical roles: sentinel lymph node biopsy, axillary lymph node dissection, and targeted axillary dissection. At Breast & Surgical Oncology at The Poche Centre, our surgeons perform the full spectrum of axillary procedures and have contributed to published research on advanced axillary techniques, ensuring every patient receives the most precise and appropriate axillary management for their situation.

The Lymphatic System and Breast Cancer

The lymphatic system is a network of vessels, nodes, and fluid that plays a central role in immunity and in the body's response to infection and disease. Lymph fluid drains from tissues throughout the body into regional lymph nodes — small, bean-shaped structures that act as filters, trapping bacteria, cellular debris, and, in the context of cancer, malignant cells.

The lymph nodes that drain the breast are located primarily in the axilla, with smaller groups above and below the collarbone. The number of axillary lymph nodes varies between individuals but typically ranges from around 10 to 30.

If breast cancer cells escape from the primary tumour into the lymphatic system, they travel through the lymphatic vessels to the axillary lymph nodes. The first node (or small group of nodes) to receive that drainage is called the sentinel node — the gatekeeper that is first in line to receive any cancer cells that have spread beyond the breast.

Whether or not the lymph nodes are involved with cancer is one of the most important prognostic factors in breast cancer. It influences staging (the classification of how advanced the cancer is), systemic treatment decisions (whether chemotherapy, targeted therapy, or hormonal therapy is recommended), and radiation therapy planning (whether radiotherapy to the axilla and nodal basins is needed in addition to the breast or chest wall).

Conditions Covered in this Section