Key takeaways:
It’s common for breast cancer to spread to nearby lymph nodes, usually in the armpit, around the collarbone, or under the breastbone.
Breast cancer lymph nodes play an important role in determining cancer stage and treatment strategy.
Lymph nodes are part of the lymphatic system, which connects different areas of your body. So, the presence of breast cancer lymph nodes increases the risk of cancer spread.
It can be scary to hear that breast cancer has spread to your lymph nodes. But this is common. In fact, about 1 in 3 people with breast cancer have lymph node involvement at the time of diagnosis. If this is the case for you, it doesn’t mean the cancer has metastasized (spread to distant parts of your body).
Here, we’ll explain what it means if your breast cancer has lymph node involvement, why it’s important, and how it impacts your treatment.
Which lymph nodes are involved in breast cancer spread?
Lymph nodes are located all throughout your body, including around your breasts. As a tumor grows, cancer cells can start to invade nearby tissues. Lymph nodes are typically the first place that breast cancer cells spread when they travel outside your breast.
The nearest lymph node groups are located:
Within your breast
In your armpit (these are usually the first nodes breast cancer cells spread to outside of your breast)
Under your breastbone (sternum) in the center of your chest
Why does lymph node spread matter?
Lymph node spread matters because it’s one of the ways that cancer cells can spread to more distant parts of your body, a process called metastasis. Lymph nodes are part of your body’s lymphatic system, which is a network of nodes and vessels that run throughout your entire body. When cancer cells are found in your lymph nodes, it means there’s a higher chance that cancer cells have traveled elsewhere. This affects both staging and treatment.
It’s important to emphasize that lymph node spread doesn’t mean that cancer has metastasized. It just means the potential is there. Breast cancer can also spread in other ways. So, lymph node involvement isn’t needed for a cancer to metastasize.
How do breast cancer lymph nodes affect staging?
Lymph node involvement is one of the main considerations in staging breast cancer, particularly for stages 1, 2, and 3. In general, the more lymph nodes that are involved, the higher the breast cancer stage.
The location of the affected lymph nodes is also important. Cancer that has spread to more distant lymph nodes is staged higher than cancer that has spread only to nearby nodes.
Breast cancer treatment: If you’re feeling overwhelmed by all the different treatments for breast cancer, we’ve created an easy-to-follow overview to help.
Staging vs. grading: Breast cancer is categorized into stages and grades. Learn more about what these mean for you and your future treatment.
Early signs of metastatic breast cancer: Most breast cancers are diagnosed before the cancer spreads. Still, it’s important to know the early warning signs so you can talk with your treatment team.
Other factors also contribute to the final determination of breast cancer stage. These include:
Tumor size and grade
Whether the cancer has spread to distant areas of your body
The receptors found on the breast cancer cells
How do breast cancer lymph nodes affect treatment?
When breast cancer has spread to your lymph nodes, there are several treatments used to treat the cancer and decrease your risk of it coming back. The most common treatments include:
Surgery to remove the tumor and any affected lymph nodes
Radiation to kill any cancer cells that remain after surgery
Systemic therapy, such as chemotherapy, to kill any cancer cells that may be circulating throughout your body
Surgery
Surgery is done to remove the tumor and, in some circumstances, the affected lymph nodes. The degree of lymph node spread can impact the surgical approach in a couple of different ways.
If only a few nearby lymph nodes are involved, the surgeon may recommend a less extensive procedure like a lumpectomy or partial mastectomy. These procedures only remove a portion of your breast.
If there’s more lymph node spread, you may need a more extensive procedure called an axillary lymph node dissection. In this procedure, a surgeon removes a large part of the axillary lymph nodes. But many people with early-stage breast cancer and limited lymph node spread don’t need this procedure.
Radiation
Radiation is often done after surgery to kill any breast cancer cells that were left behind. For cancers with more lymph node involvement, radiation may also be done before surgery to shrink the tumor and nodes before removing them.
Chemotherapy
Systemic therapy, like chemotherapy, uses medicines that are given to your entire body, often through an IV (intravenous) infusion. Systemic treatments kill the cancer cells before they are able to form new tumors.
Chemotherapy is more frequently recommended for breast cancer with lymph node involvement. But other factors — such as the grade, receptor status, and other tests like oncotype — also help your healthcare team decide if chemotherapy will be helpful.
How do breast lymph nodes affect prognosis?
Breast cancer lymph nodes play an important role in determining prognosis. Because it shows the cancer has spread beyond your breast, it can sometimes mean the cancer is harder to treat. It also means the cancer is more likely to come back.
But it’s important to keep in mind that the number of lymph nodes involved is only one piece of the overall prognosis. Other factors also play an important role, such as:
Tumor size
Other health conditions
It’s difficult to report specific survival rates because they’re affected by several different factors. Also, cancer statistics apply to large groups of people, not individuals.
In general, breast cancer that hasn’t spread outside the breast has a nearly 100% survival rate at 5 years. If the cancer has spread to nearby lymph nodes, the 5-year survival rate decreases to 87%. Keep in mind that this is based on data from up to 10 years ago, and treatments and survival rates have improved since then.
Frequently asked questions
You often can’t feel if breast cancer has spread to your lymph nodes. About 1 in 3 breast cancers will have lymph node involvement at the time of diagnosis. Only a small number of these will have something you can feel on a physical exam.
When breast cancer spreads to your lymph nodes, it starts on the cellular level. So, breast cancer lymph nodes aren’t often swollen or large.
If breast cancer lymph nodes get large or swollen, they can sometimes cause discomfort. But this isn’t common. Most of the time, you can’t feel when breast cancer is in your lymph nodes.
A sentinel node biopsy is a procedure that tests for breast cancer spread to lymph nodes. This is often done during surgery to remove the primary cancer.
The “sentinel nodes” are the first lymph nodes that cancer cells are likely to reach based on the tumor’s location. Before the surgery, a breast surgeon can inject a special dye into your breast to figure out which nodes are the sentinel nodes. During surgery, a small sample of one or more sentinel nodes is removed and tested for cancer cells.
A potential side effect specific to lymph node surgery is lymphedema, or swelling of the arm. This happens because lymph nodes play an important role in lymphatic drainage of your arm. The risk is higher for people who have a full lymph node dissection compared with those who only have a sentinel node biopsy.
You often can’t feel if breast cancer has spread to your lymph nodes. About 1 in 3 breast cancers will have lymph node involvement at the time of diagnosis. Only a small number of these will have something you can feel on a physical exam.
When breast cancer spreads to your lymph nodes, it starts on the cellular level. So, breast cancer lymph nodes aren’t often swollen or large.
If breast cancer lymph nodes get large or swollen, they can sometimes cause discomfort. But this isn’t common. Most of the time, you can’t feel when breast cancer is in your lymph nodes.
A sentinel node biopsy is a procedure that tests for breast cancer spread to lymph nodes. This is often done during surgery to remove the primary cancer.
The “sentinel nodes” are the first lymph nodes that cancer cells are likely to reach based on the tumor’s location. Before the surgery, a breast surgeon can inject a special dye into your breast to figure out which nodes are the sentinel nodes. During surgery, a small sample of one or more sentinel nodes is removed and tested for cancer cells.
A potential side effect specific to lymph node surgery is lymphedema, or swelling of the arm. This happens because lymph nodes play an important role in lymphatic drainage of your arm. The risk is higher for people who have a full lymph node dissection compared with those who only have a sentinel node biopsy.
The bottom line
Breast cancer staging and treatment may change depending on the number and extent of lymph nodes involved. This is because lymph nodes are one way that cancer cells can travel to other parts of your body. If your breast cancer has lymph node involvement, it doesn’t mean your breast cancer has metastasized. It just means you may need more aggressive treatment, like radiation or chemotherapy. Most breast cancers with lymph node spread can still be fully treated, allowing you to live free of cancer after treatment.
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References
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Kay, C., et al. (2023). The role of nodes and nodal assessment in diagnosis, treatment and prediction in er+, node-positive breast cancer. Journal of Personalized Medicine.
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