You may hear a lot about lymph nodes during breast cancer treatment, and here’s what you need to know about why they matter and how they affect your care. First, what are lymph nodes? Why are they checked? What does it mean if cancer is found in your lymph nodes? How does this affect treatment or recovery? Here’s a breakdown of the lymphatic system’s role in breast cancer and the advances making breast surgery smoother and more precise.
The lymphatic system
Acting as a key part of your body’s drainage and immune system, the lymphatic system can be thought of as a second circulatory system. Much like blood flows through the body’s veins and arteries, a network of lymph nodes and vessels moves lymph – a clear fluid that carries immune cells, proteins and waste – throughout the body. This clearance system helps fight infections and filter out harmful substances, including cancer cells. It’s also widespread; if you laid out all of the blood and lymph vessels in the body end-to-end, they would circle the earth multiple times!
Lymph node involvement in breast cancer
The lymph nodes are especially important in breast cancer because the ones in your underarm, the axillary lymph nodes, are usually the first place breast cancer can spread to. And since the lymph system spreads all throughout the body, it’s best to find it there early to try to prevent cancer from spreading further.
Discovering if cancer has reached the lymph nodes will change your diagnosis from node-negative to node-positive, affecting cancer stage, treatment plans and surgical approaches. Whether lymph nodes contain cancer or not helps doctors understand how far the disease has spread. Having fewer affected nodes usually means a better prognosis. Status is also related to tumor size; the larger the tumor, the more likely it is that the cancer has spread to the axillary lymph nodes (lymph node-positive).
Checking and testing lymph nodes and mapping the sentinel node
Some of the ways that your care team may check your lymph nodes include:
- An initial physical exam is common to feel lymph nodes for swelling, tenderness or other signs of inflammation.
- Imaging tests like ultrasound, MRI or CT scans can help spot nodes that look abnormal in size or shape.
- Fine needle aspiration (FNA) might be used if a specific lymph node looks suspicious in imaging or during a physical exam. This procedure involves a small needle that takes a sample of cells from the node for analysis.
- Sentinel lymph node biopsy (SLNB) and mapping is the standard approach used to determine whether breast cancer has spread. A tracer dye and/or radioactive material helps visualize the “sentinel nodes,” the first lymph nodes that drain fluid from the breast. These nodes are then removed and tested for cancer cells to assess the risk of the disease spreading beyond the breast.
- Axillary lymph node dissection (ALND) involves removing several lymph nodes from the underarm area. This procedure used to be common. Now, thanks to new techniques and tools, it is reserved for cases where multiple nodes have already been confirmed to be affected by cancer.
Before the 1970s, removing most or all lymph nodes under the arm as part of a radical mastectomy was the standard of care. Fortunately, SLNB is now the standard technique for identifying the sentinel nodes, significantly reducing the number of nodes removed for most patients.
Sentinel lymph node mapping and biopsy are typically performed during breast surgery using a radioactive tracer, sometimes with a blue dye, to visualize the sentinel nodes. During the procedure, the tracer is injected near the tumor and tracked as it moves through the lymphatic vessels to the sentinel node. This mapping helps the surgeon precisely locate and remove the correct node while minimizing tissue damage. Alternative tracers, such as fluorescent dyes and coated iron oxide particles, are also being studied as potential non-radioactive mapping options for the future. Ask your surgeon what’s the best option for you.
Once removed, lymph nodes are reviewed by a pathologist. If no cancer cells are found, you may be able to avoid more surgery and additional treatment. If cancer is present, chemotherapy or targeted radiation may be recommended to lower chances of cancer recurrence. Because lymph node status affects your stage, it may also determine your eligibility for clinical trials. Managing lymph nodes remains an active area of research as experts refine which patients benefit most from SLNB while minimizing side effects. Today’s minimally invasive techniques reduce complications like lymphedema and help preserve quality of life.
Lymphedema and reducing its risk
Lymphedema is swelling in the arm that can feel heavy or limit movement. It happens when lymph fluid builds up after nodes are damaged or removed, and it can last months or longer. The risk of developing lymphedema is greatly reduced with a SLNB procedure as compared to an ALND because more nodes are removed with ALND. While lymphedema can’t be prevented, it can be managed with strategies like physical therapy and compression garments that help drain the lymph fluid.
Ask Questions
Knowing whether breast cancer has spread to the lymph nodes is one of the most important steps in personalizing treatment. Thanks to ongoing advancements, many people can now avoid more invasive surgery and recover faster. If you have questions or concerns about your lymph nodes or any step in your care, talk with your treatment team. They’re there to help you understand your body and your options.
Content covered in the Know More Educational Series may be an emerging area in research or technology. Talk with your doctor about what is right for you.
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Downloadable Resource:
Checking the Lymph Nodes for Breast Cancer Spread – Downloadable PDF
Read More:
Lymphatic System and Axillary Nodes
6 Ways Your Care Team Learns About Your Breast Cancer
Axillary Lymph Node Fact Sheet
Watch & Hear More:
What to Know About Breast Cancer-Related Lymphedema
Real Talk: Getting a Second Opinion; A patient story
Lumpectomy Surgery: Tumor & Lymph Node Removal Explained
