What Does It Mean If Breast Cancer Spreads to Your Lymph Nodes?


Medically reviewed by Krystal Cascetta, MD — Written by Ann Pietrangelo on March 30, 2021

After you get a breast cancer diagnosis, it likely won’t be long before your doctor starts talking to you about lymph nodes. Lymph node involvement is an important part of staging and treatment with breast cancer.

This article will help explain what it means when breast cancer spreads to the lymph nodes, how it affects cancer staging, and the types of treatment that are typically used.

What are lymph nodes?

You have hundreds of lymph nodes throughout your body. Your lymph nodes are part of your lymphatic system, which, in turn, is part of your immune system.

Lymph nodes are little bean-shaped structures that contain immune cells that help fight infection. They’re connected by a system of lymph vessels that carry fluid throughout your body. As fluid passes through your lymph nodes, they filter out harmful substances.

Cancer spreads when cancer cells break away from the primary tumor. In breast cancer, these cells are most likely to reach the lymph nodes closest to the affected breast.

Usually, these lymph nodes are under the arm, but there are also clusters of lymph nodes near the collarbone and breastbone.

The ones that are closest to your breast are called sentinel lymph nodes. The nodes under your armpit are called axillary lymph nodes.

Credit: Wenzdai Figueroa

Even if cancer has reached nearby lymph nodes, it doesn’t mean it has spread to other areas. But cancer that reaches the lymph system or bloodstream has a greater potential to travel to other parts of the body.

Breast cancer that has spread to lymph nodes may be treated more aggressively than if it hadn’t reached these nodes.

The 5-year survival rate for breast cancer that hasn’t reached nearby lymph nodes is 99 percent versus 86 percent when it has.

Breast cancer staging and lymph nodes

After an initial cancer diagnosis, you’ll need to know if it has spread beyond the primary tumor. If you have enlarged lymph nodes, your doctor may be able to perform a needle biopsy. Otherwise, the lymph nodes can be checked when you have breast surgery.

Your doctor will assign a clinical stage based on:

  • a physical exam
  • imaging tests
  • a biopsy of the tumor

After surgery, you’ll have more detailed information from the breast tissue and lymph nodes. This information helps provide the pathological stage.

Lymph node involvement is a key factor in staging breast cancer. In the TNM staging system:

  • T is for tumor size
  • N represents lymph node involvement
  • M is for metastasis (spread)

Here’s a closer look at what to know about cancer cells and lymph node involvement.

Lymph node involvement

  • NX: Cancer cells in the lymph nodes can’t be measured.
  • N0: No cancer cells have been found in nearby lymph nodes.
  • N1: Cancer has spread to one to three underarm lymph nodes, or a small number of cancer cells have been found in lymph nodes near the breastbone during sentinel node biopsy.
  • N2: Cancer has spread to four to nine underarm lymph nodes, or mammary lymph nodes are enlarged.
  • N3: Cancer has spread to 10 or more axillary lymph nodes and one site is larger than 2 millimeters (mm), or cancer is found in lymph nodes under the collarbone and one site is larger than 2 mm.

Other things that can influence breast cancer staging include:

  • Tumor grade. This has to do with how abnormal the cancer cells appear under a microscope. The higher the grade, the more aggressive the cancer.
  • Biomarker tests. The cancer cells will be checked for certain receptors, such as estrogen, progesterone, and HER2 (a growth-promoting protein found on the outside of breast cells). All of these can help fuel the growth of cancer cells in the breast.

All these factors are combined to determine the stage.

Are there symptoms of breast cancer in the lymph nodes?

You probably wouldn’t notice if a few cancer cells reached a lymph node. As the number of cancer cells grows, symptoms can include lumps or swelling in the armpits or around the collarbone.

It’s possible to have enlarged lymph nodes even if you haven’t discovered a lump in your breast. There are also noncancerous conditions that cause enlarged lymph nodes in an area close to the breasts.

If you notice enlarged lymph nodes but no other symptoms or signs, schedule an appointment with a doctor.

What are the treatment options?

Breast cancer treatment options are based on a variety of factors, including:

  • the hormone and HER2 receptor status of the breast cancer cells
  • the tumor grade
  • the cancer stage
  • your genetics or inherited genes


The two main types of surgery for the primary breast tumor are breast-conserving surgery (lumpectomy) or mastectomy.

  • A lumpectomy involves the removal of the breast tumor and any surrounding tissue that’s been affected. Your surgeon will attempt to preserve the rest of the breast.
  • A mastectomy involves removing the entire breast, and in some cases, a few or several of the lymph nodes near the breast will be removed, too.


Radiation therapy often follows surgery, especially if there’s lymph node involvement. It can target specific lymph nodes, tumors, or sites where a tumor was surgically removed.

The goal of radiation therapy is to focus on cancer cells that may still be present in specific areas, like the lymph nodes or tissue that was close to the tumor that was removed.

Radiation therapy can damage the DNA of cancer cells, which helps destroy them. It doesn’t target your entire body like chemotherapy, so there’s a lower risk of harming healthy cells.

There are two types of radiation:

  • External beam radiation. This is the most common type of radiation therapy for breast cancer. It involves a large machine that sends beams of radiation to a specific area of your breast where there may still be cancer cells.
  • Internal radiation. Also known as brachytherapy, this method is typically used after a lumpectomy or in early stage breast cancer. It involves placing radioactive pellets or seeds inside a specific area of the breast through a catheter. The pellets are usually left there for around 10 to 20 minutes and then removed.

Lymph node dissection

A lymph node dissection is a surgical procedure that involves the removal of lymph nodes near the tumor. A sample of the lymph node tissue is then examined for signs of cancer cells.

This treatment may involve:

  • regional lymph node dissection, which is the removal of some lymph nodes near the tumor area
  • radical lymph node dissection, which is the removal of all the lymph nodes near the tumor area

Removing a few lymph nodes doesn’t always cause problems and it doesn’t weaken your immune system.

But missing lymph nodes can cause lymph fluid to back up, a condition called lymphedema. The risk of lymphedema increases with the number of lymph nodes removed. Once it develops, this can become a long-term problem.

Other side effects may include numbness and decreased range of motion in the arm and shoulder.

In 2017, results of a large clinical trialTrusted Source showed that axillary lymph nodes (those under your arm) don’t always have to be removed, even when cancer cells are found in sentinel nodes (those closest to the breast). This applies to those with early stage breast cancer who have a lumpectomy.

Looking at 10-year outcomes, the study found that removal of the sentinel lymph nodes alone didn’t seem to affect survival rate when compared to axillary lymph node dissection.


Chemotherapy drugs can destroy cancer cells throughout your body.

Your doctor may suggest chemotherapy when there’s lymph node involvement or if there’s a chance that cancer has spread beyond the lymph nodes.

Chemotherapy may be a good choice in very aggressive cancers or those that are negative for hormone and HER2 receptors.

Hormone therapy

Hormone therapies can block estrogen receptors or lower estrogen levels. This may be an effective treatment option for breast cancer that has a hormone receptor status of estrogen-positive (ER+).

This type of therapy is also called endocrine therapy. These medications include:

  • aromatase inhibitors
  • luteinizing hormone-releasing hormone (LHRH) agonists
  • tamoxifen

Targeted therapies

Targeted therapies attack specific types of cancer cells. For example, HER2-positive breast cancers can be treated with:

  • monoclonal antibodies
  • tyrosine kinase inhibitors

Other targeted therapies include:

  • cyclin-dependent kinase inhibitors
  • mTOR inhibitors
  • PARP inhibitors

Compared to chemotherapy, targeted therapies tend to do a better job of telling the difference between cancer cells and normal cells. Because of this, these therapies can damage cancer cells, while limiting the harm to normal cells.


Immunotherapy is a type of biologic therapy that helps your immune system recognize and attack cancer cells.

Some examples of immunotherapy for breast cancer include the following drugs that are given as intravenous (IV) infusions:

  • pembrolizumab (Keytruda)
  • atezolizumab (Tecentriq)

Clinical trials

Clinical trials are available for many types and stages of breast cancer. An oncologist can help determine if there’s a trial that’s a good fit for you.


Understanding your cancer and treatment

Not all breast cancers are alike. Someone else’s experience with their treatment may be completely different from yours. Understanding your type and stage can help make sense of your doctor’s recommendations. This may help you feel better about your treatment choices.

A big part of cancer treatment is the relationship between you and your oncology team. Here are some things you’ll want to know about early on so you’re well informed about your specific type of breast cancer:

What to find out from your doctor

  • the cancer stage
  • the tumor grade
  • your hormone and HER2 receptor status
  • genetic testing
  • your surgery options: lumpectomy, mastectomy, lymph node biopsy, breast reconstruction
  • your treatment goals, side effects, and how to know if the treatment is working

Oncologists meet with cancer patients every day and it’s their job to see you as a whole person. Express your wants and needs. Rest assured that no question is too insignificant to ask.

The bottom line

When breast cancer is found in the lymph nodes, it means that cancer has spread from the primary tumor and is at least stage 2.

Lymph node involvement is an important part of staging and in determining which treatments are most likely to be effective.

Knowing the specifics of your breast cancer can help you partner with your doctor and be an active participant in your treatment.

Posted in: Emotional/Mental Health, Genetics, In Treatment, Just Diagnosed, Mastectomy, Medical/Science, Post Treatment, Recurrence, Research, Side Effects, Staging