Lymph nodes are small, bean-shaped glands that are a part of the body’s lymphatic system. This system, a component of the immune system, is responsible for filtering a clear fluid called lymph, which contains immune cells like lymphocytes and macrophages. These cells identify and eliminate foreign substances, damaged cells, and cancer cells. For breast cancer, lymph nodes are particularly relevant because they serve as a common pathway for cancer cells to spread beyond the original tumor.
Purpose of Lymph Node Removal in Breast Cancer
Lymph node removal in breast cancer serves two main purposes. The first is to accurately stage the cancer, determining if cancer cells have spread from the breast to nearby lymph nodes. This information is important for understanding the extent of the disease and predicting its potential behavior.
Second, it guides subsequent treatment decisions. If cancer cells are found in the lymph nodes, it indicates a higher likelihood that the cancer could have spread to other parts of the body, even if not yet detectable. Therefore, knowing the lymph node status helps medical teams determine the most effective therapies, which may include chemotherapy, radiation, or hormone therapy, in addition to surgery.
Types of Lymph Node Removal Procedures
The number of lymph nodes removed varies by procedure. The two primary types are sentinel lymph node biopsy (SLNB) and axillary lymph node dissection (ALND). These procedures differ in invasiveness and the typical number of nodes extracted.
Sentinel lymph node biopsy (SLNB) is a less invasive approach that identifies and removes only the “sentinel” lymph node or nodes. A sentinel node is considered the first lymph node or group of nodes to which cancer cells are most likely to spread from the primary breast tumor. To locate these nodes, a surgeon injects a radioactive substance, blue dye, or both near the tumor, which travels to the sentinel nodes. The surgeon removes these nodes, typically one to five, sometimes more. If cancer-free, further lymph node removal is often unnecessary, minimizing side effects.
In contrast, an axillary lymph node dissection (ALND) is a more extensive surgical procedure. It is usually performed if cancer cells are confirmed in sentinel nodes, if lymph nodes are enlarged and contain cancer before surgery, or in more advanced breast cancer cases. During ALND, a larger group of lymph nodes from the armpit (axilla) are removed. ALND removes 10 to 40 nodes, often between 10 and 25. This procedure aims to remove any cancerous nodes in the region to reduce the risk of local recurrence.
Factors Influencing the Number of Lymph Nodes Removed
The number of lymph nodes removed in breast cancer surgery varies significantly. Several factors contribute to this variability. Cancer characteristics play a role, including tumor size, aggressiveness, histological type, and whether cancer cells are already detected in lymph nodes. Larger tumors or confirmed lymph node involvement may necessitate removing more nodes.
Patient anatomy, especially lymphatic drainage patterns, also affects how many sentinel nodes are identified and removed. Prior treatments, like neoadjuvant chemotherapy before surgery, can influence the number of lymph nodes removed. Surgeon experience and practices also contribute to the variation in nodes removed during SLNB.
Potential Side Effects of Lymph Node Removal
Lymph node removal, while important for breast cancer treatment, can lead to several potential side effects. Lymphedema, a common complication, is swelling typically occurring in the arm or hand on the surgical side. This swelling develops when lymphatic drainage is disrupted, causing lymph fluid buildup in tissues. Lymphedema risk is generally higher after ALND (20-30% of patients) compared to SLNB (5-17%).
Another common side effect is numbness, tingling, or pain in the armpit, upper arm, or chest area. This can result from nerve damage during surgery. The discomfort can range from mild to persistent, sometimes lasting for an extended period after surgery.
Patients may also experience restricted range of motion or stiffness in the shoulder and arm. This can be due to scar tissue or ongoing swelling in the area. Disruption to the lymphatic system can also increase infection risk in the affected arm or hand, requiring careful monitoring. Management strategies, including physical therapy and compression garments, can help alleviate these side effects.