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Lymph Nodes in Breast Cancer: What They Mean, and Why They Matter

Joanna Jan, MDKatie E. Golden, MD
Written by Joanna Jan, MD | Reviewed by Katie E. Golden, MD
Published on October 12, 2021

Key takeaways:

  • Lymph nodes are part of the lymphatic system, which breast cancer cells can use to travel and spread to other areas of the body.

  • It is common for breast cancer to spread to nearby lymph nodes, usually in the armpit, around the collarbone, and under the breastbone.

  • Lymph node involvement helps to determine breast cancer staging and treatment recommendations. 

A person examining lumps in their breast.
RealPeopleGroup/E+ via Getty Images

It can be scary to hear that breast cancer has spread to your lymph nodes. But this is common in breast cancer and does not mean the cancer has metastasized (spread to more distant parts of the 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 options.

How does breast cancer spread?

As a tumor grows, cancer cells can start to invade nearby tissues. They can also break away from the tumor and spread to other areas in the body. There are two ways that cancer cells can travel to more distant parts of the body: through the bloodstream or through the lymphatic system.

Lymph nodes are glands in our bodies that are part of the lymphatic system. When someone is diagnosed with breast cancer, their lymph nodes are often tested for signs of cancer cells. This is because lymph nodes are typically the first place that breast cancer cells spread when they travel outside the breast.

But it’s important to understand that when cancer cells are found in the lymph nodes, this doesn’t mean that cancer has metastasized. It just means the potential is there, and so the cancer is treated a little differently. We will explain this in more detail later in the article.

Which lymph nodes are involved in breast cancer spread?

Several groups of lymph nodes are near the breast, and these are the ones that breast cancer can spread to first.

A 3D illustration of the lymphatic system including supraclavicular lymph nodes, tonsils, axillary lymph nodes, internal mammary lymph nodes, and lymphatic vessels.

The nearest lymph node groups are:

When breast cancer spreads to lymph nodes, it can sometimes cause them to become fixed in position and stuck together (or matted). Lymph nodes that are matted generally have more cancer cells than those that are still mobile or movable.

Why does lymph node spread matter?

Because they are the first place outside of the breast where breast cancer usually spreads, lymph nodes provide important information about how much the cancer has progressed. So, this plays a role in staging and determining which treatment options are best.

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 locations of the lymph nodes involved is also important. Cancer that has spread to more distant lymph nodes is staged higher than cancer that’s spread only to nearby nodes.

But other factors also contribute to the final determination of breast cancer stage. These include tumor size and grade, presence of metastasis to distant areas in the body, and receptors on the breast cancer cells.

Treatment

When breast cancer has spread to the lymph nodes, there are several treatments used to cure the cancer and decrease the risk of recurrence. The most commonly used 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 the body.

Surgery is done to remove the tumor and, in some circumstances, the affected lymph nodes as well. And 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 the breast. But if more lymph nodes are involved, a total mastectomy may be recommended. 

Someone who has more lymph node spread may also have a more extensive axillary lymph node dissection during their surgery. In this procedure, a surgeon removes a large part of the axillary lymph nodes. But many people with early stages and less lymph node spread do not need this procedure.

Radiation is often done after surgery to kill any breast cancer cells that were left behind. In cancer that has more lymph node involvement, radiation may be done before surgery to shrink the tumor and nodes before removing them. 

Systemic therapy, like chemotherapy, are medicines that are given to the entire body, often through an IV infusion. This type of treatment is almost always recommended for breast cancer with lymph node involvement. This is because lymph node spread means that cancer cells may be circulating in the body, even if they can’t be detected with testing. Systemic treatments kill the cancer cells before they are able to form new tumors.

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 the body. The good news is that there are effective treatments for breast cancer that has spread to the lymph nodes. And most breast cancers with lymph node spread can be cured, allowing you to live free of cancer after treatment. 

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Why trust our experts?

Joanna Jan, MD
Written by:
Joanna Jan, MD
Joanna Jan, MD, is board-certified in internal medicine and licensed to practice medicine in the state of Pennsylvania. In 2017, she received her board certification from the American Board of Internal Medicine.
Katie E. Golden, MD
Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

References

Breastcancer.org. (2020). Hormone receptor status.

Breastcancer.org. (2021). Radiation therapy.

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Hashem, T., et al. (2021). Intra-mammary lymph nodes, an overlooked breast cancer prognostic tool? World Journal of Surgical Oncology.

Jin, R., et al. (2019). Clinical characteristics and prognostic analysis of ipsilateral supraclavicular lymph node metastases in breast cancer patients: A retrospective study. International Journal of Clinical and Experimental Pathology.

Lian, C. L., et al. (2021). Staging for breast cancer with internal mammary lymph nodes metastasis: Utility of incorporating biologic factors. Frontiers in Oncology.

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National Cancer Institute. (2017). Extensive lymph node removal doesn't improve survival in some women with early-stage breast cancer.

National Cancer Institute. (2015). Lymphatic system.

National Cancer Institute. (2016). Metastasis.

National Cancer Institute. (2018). Matted lymph nodes.

National Cancer Institute. (2019). Sentinel lymph node biopsy.

GoodRx Health has strict sourcing policies and relies on primary sources such as medical organizations, governmental agencies, academic institutions, and peer-reviewed scientific journals. Learn more about how we ensure our content is accurate, thorough, and unbiased by reading our editorial guidelines.

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