Triple-Negative Breast Cancer (TNBC)

Medically Reviewed by Poonam Sachdev on February 20, 2024
Written by WebMD Editorial Contributor, Kristin Mitchell, Kris Martins
12 min read

Triple-negative breast cancer is a type of breast cancer in which cancer cells test negative for three of the main things that are usually found in breast cancer – the hormones estrogen and progesterone, and a protein called HER2. These receptors typically fuel breast cancer growth, and doctors can use treatments like hormone therapy or other drugs. But with triple-negative breast cancer, fewer treatment options are available because of the absence of these receptors.

Triple-negative breast cancer is more aggressive than other forms. It’s more likely to have spread beyond your breast at the time it’s found, and there’s a higher chance it will come back within the first 3 years after treatment. It’s also more likely to be fatal within the first 5 years. But once you pass those milestones, your odds of beating it are about the same as someone with any other type of breast cancer.

As this kind of cancer doesn’t respond to some of the medications that work for other types, some of the targeted therapies that work for certain cancer cells, like those for HER2-positive breast cancer, will not work well. But that doesn’t mean it can’t be treated. Once you’re diagnosed, your doctor will work with you to decide the best treatment plan.

The symptoms of triple-negative breast cancer, once they occur, are often the same as those of other breast cancer types, and include:

  • A lump or mass in the breast
  • Breast or nipple pain or redness
  • A nipple that turns inward or has a discharge
  • Swelling in all or part of a breast, even if you don't feel lumps
  • Dimpled skin, which may look like an orange peel
  • Nipple or breast skin that’s dry, flaking, thickened, or red
  • Swollen lymph nodes under your arm or near your collarbone
  • Breast warmth, itchiness, or irritation
  • Change in breast size, shape, or symmetry

Doctors aren't sure what makes you more likely to get triple-negative breast cancer. Not many women get this form of cancer – it only affects up to 20% of those who have breast cancer. You're most at risk for triple-negative breast cancer if you:

  • Are Black or Hispanic
  • Are under 40
  • Have what your doctor will call a BRCA mutation (a change in a gene), especially the gene BRCA1
  • Are inactive and have obesity after menopause

There's no way to know which type of breast cancer you have until you’re tested by a doctor. Usually, triple-negative breast cancer is seen through a mammogram, but sometimes you need an ultrasound to see things that can't be found during a mammogram. This can include lumps, fluid-filled masses, or abnormal areas that may be blocked by dense breast tissues in the mammogram. If doctors think they see cancer through either of these imaging tests, they may do a biopsy, which involves cutting out a little bit of the tissue to test the cells.

A doctor called a pathologist will look at your biopsied tissue under a microscope. The structure will confirm if the cells are normal, precancerous, or cancerous. If it’s cancer, they’ll do more tests to figure out the exact kind. If testing shows that your cancer cells don't have estrogen, progesterone, or HER2 receptors, then it’s diagnosed as triple-negative breast cancer. It might take a couple of weeks to get biopsy results.

The doctor will also “stage” your cancer. That’s when they figure out how much of it there is and where it is in your body. They'll do this through tests, including:

  • Magnetic resonance imaging (MRI). Your doctor might use this to find out the exact size and place of the cancer. An MRI can also help them check for other tumors in one or both breasts.

  • Ultrasound. Similar to the way your doctor would use this soundwave imagery to diagnose cancer, they may choose to use it to look for cancer in more places, such as the other breast, under your arms, and your liver.

  • Computed tomography (CT) scan. Working to pull many images of your body to show a complete picture of a certain area, a CT scan is usually used to look at your chest and belly to check if breast cancer has spread to other organs, like your lungs or liver.

  • Positron emission tomography (PET) scan. You may get a PET scan if there's a chance that the cancer has spread to other parts of your body. To find out if it has, PET scans involve injecting radioactive sugar into your blood and watching to see if it gathers in cancer cells. Your doctor may combine this with a CT scan to get a detailed picture.

Triple-negative breast cancer stages

Most doctors use a standard staging system set by the American Joint Committee on Cancer (AJCC) called the TNM system. The acronym stands for three key pieces of information they use to tell you which stage of cancer you have.

  • T - extent or size of the tumor. This is ranked on a scale of 0 to 4. The higher the number, the bigger the tumor or the more it has spread to the breast area.
  • N - spread to nearby lymph nodes. On a scale of 0 to 3, this tells you if or how many lymph nodes near the breast the cancer has spread to.
  • M - spread to distant organs. Either a 0 or 1, this value says whether the cancer has reached organs farther away, like your bones, liver, or lungs.

Another common staging system you may hear uses other terms and phrases. 

  • In situ. You have abnormal cells, but they haven't spread to nearby tissue.
  • Localized. There's only cancer in the place where it started, and there aren't any signs that it has spread.
  • Regional. The cancer has spread to lymph nodes, tissues, or organs that are close by.
  • Distant. The cancer has grown farther away to other parts of the body.
  • Unknown. There isn't enough information to figure out the stage.

These commonly used staging systems help your doctor and others on your health care team understand how serious your cancer is, your survival rate, and the right treatment plan for your situation. Based on your breast cancer stage, they may also suggest certain clinical studies.

Once you're diagnosed with TNBC, you'll likely have a lot of questions. Be prepared to ask your doctor important questions, including:

  • Which medications do you recommend?
  • What stage is my cancer? Has it spread to lymph nodes (glands near the breast) or other areas?
  • Should I have chemotherapy before or after surgery?
  • What type of surgery will I need?
  • Will I need radiation treatments?

Triple-negative breast cancer is usually treated with a combination of surgery, radiation, and chemotherapy.

Chemotherapy

Chemotherapy, a medicine that kills cancer cells, will likely be the first thing your doctor tries. You can get it by a needle into a vein or in a pill. When it’s caught early, this type of cancer may respond better to chemo than others do. Your doctor can use chemo in one of three ways:

  • Neoadjuvant therapy is when you get chemo before surgery to shrink the tumor and make the operation easier. That makes it the preferred approach if you have locally advanced breast cancer but your doctor doesn’t think they can operate yet, or if your cancer makes it unlikely that your breast can be saved.
  • Adjuvant therapy is used after surgery. You might get it if you have a large tumor or if your lymph nodes are involved. You’re more at risk for relapse. Other types of adjuvant therapy, like hormone treatments, won’t work with triple-negative breast cancer

  • Platinum chemotherapy is a specific type of chemo that uses common platinum-based medicines like carboplatin or cisplatin either before or after surgery. A study found that it improves survival and lowers the chance of cancer returning if you have early triple-negative breast cancer.

    Immunotherapy is used along with chemo in cases where the cancer has spread and surgery is not an option. Immunotherapy uses medicines to boost your immune system so it can better fight cancer cells and stop them from spreading. This choice works particularly well for triple-negative breast cancer since the cancer cells have more genetic mutations, making them easier for the immune system to target. It can be used along with chemo in cases where the cancer has come back locally and surgery is not an option. Immunotherapy can also help before and after surgery for stage II and III cancers.

Lymph node procedures

If there's a chance a main tumor may spread cancer to a specific lymph node, your doctor may suggest a sentinel lymph node biopsy. During this procedure, they'll find, remove, and test the lymph node to find out if there's cancer in it and if it has spread to others around it. If so, they may do more biopsies to remove other lymph nodes or schedule a follow-up surgery. 

Axillary lymph node dissection 

This removes 10 to 40 lymph nodes under your arms to check for cancer spread and is usually paired with a mastectomy or breast-conserving surgery. You may need this procedure if:

  • Your sentinel lymph node biopsy shows three or more of your underarm lymph nodes have cancer cells.
  • You can feel swollen underarm or collarbone lymph nodes before surgery, they're seen on imaging tests, or a biopsy shows cancer.
  • The cancer grows beyond the lymph nodes.
  • Your sentinel lymph node biopsy shows that you have cancer cells after you had chemotherapy to shrink the tumor before surgery.

Surgery 

Surgery can be one of two types. Many doctors think that because triple-negative breast cancer is aggressive, it’s best to do a mastectomy to remove the entire breast. This tends to happen if:

  • You have several tumors.
  • The cancer is in your skin.
  • You have a tumor in your nipple.
  • You already had cancer in that breast.
  • The tumor is large.
  • There are calcium deposits or other abnormal cells in your breast.

Your doctor may decide it’s OK to do a lumpectomy and remove only the tumor and the tissues around it.

Radiation 

Radiation is often used after surgery to kill any cancer cells still in the area. The goal is to stop the cancer from coming back. It’s more common after a lumpectomy.

Targeted drug therapy

This type of treatment uses medicines that target certain proteins on breast cancer cells that help them grow, spread, and live longer. These drugs enter the bloodstream and work their way all across your body, killing cancer cells or slowing down their growth along the way. This is usually a treatment used when breast cancer has spread farther into the body and when surgery isn't a choice. 

Targeted therapy for triple-negative breast cancer usually involves an antibody-drug conjugate (ADC), which combines an antibody with a chemo drug. When it attaches to cancer cells, it brings the chemo directly to them. This helps lower the chances that chemo affects your healthy cells.

Taking part in a clinical trial

With so much research on new treatments, it’s a good idea to ask your doctor if clinical trials might be right for you. Clinical trials help scientists test new drugs to see if they’re safe and if they work. It's often a good way to get a new medicine that isn't available to everyone.

Treatment side effects

Treatment may make triple-negative breast cancer go away. It depends on the size of your tumor, how quickly your cancer grows, and whether the cancer has spread to the lymph nodes or other parts of your body. Common triple-negative cancer treatment side effects include:

  • Hair loss within 2 to 4 weeks of starting chemotherapy
  • Nausea for a day or two after chemo
  • Tiredness or brain fog after chemo or radiation therapy (which is sometimes called “chemo brain”)
  • Vomiting

After your treatment is over, your doctor will want to see you often to make sure the cancer doesn't return. For the first 3 years, you'll likely see them every 3 to 6 months. For 2 years after that, you'll probably visit every 6 to 12 months. Once you've been cancer-free for 6 years, you'll probably go back only once a year. Tell the doctor right away if you get any new symptoms or if you have pain or other problems that relate to your breasts.

It’s hard to say exactly what the odds are because cancer affects everyone differently. Plus, how well you do depends on how early you catch the cancer and how well you respond to treatment.

In general, about 91% of all women with localized triple-negative breast cancer are still alive 5 years after diagnosis. But your cancer stage is one of the most important things doctors use to help decide your specific prognosis.

For instance, if the N group of your TNM stage has a number after it, meaning it has spread to the lymph nodes near the breast (regional), the 5-year relative survival rate is about 65%. If your M group is M1, which means that the cancer has spread to distant places, the 5-year relative survival rate is 12%.

 

Although triple-negative breast cancer is more likely to return to another part of your body than other forms, the chance that this will happen drops over time. About 40% of people with stage I-III triple-negative breast cancer will have it come back after treatment. The odds of getting it again peak around 3 years of treatment and falls quickly after that. But if you do keep breast tissue after surgery or other treatment, your odds do not go down over time.

Though everyone's situation is different, the risk factors for triple-negative breast cancer recurrence are similar to those of other breast cancers, including:

  • Getting your first diagnosis at age 35 or younger
  • Large tumors
  • If your lymph nodes are involved
  • Having a lumpectomy without radiation therapy
  • Your cancer stage

If the cancer does come back, the symptoms could vary depending on if it's local, regional, or distant. For instance, local recurrence usually shows up as symptoms around your breasts or surgery areas; regional recurrence would affect your arms, chest, or collarbone area; and distant could cause you to feel sick or feel pain wherever the cancer has spread.

Your doctor will use the same type of tests for your first diagnosis to check for cancer that has come back. They'll also review your previous treatment plan and the location of the returning cancer to decide how to treat it next.

 

No one will understand what you’re going through better than someone else who has this type of breast cancer. In addition to information about the disease, organizations like the American Cancer Society (www.cancer.org) and the Triple Negative Breast Cancer Foundation (www.tnbcfoundation.org) can connect you with support groups. You can also check online for groups that meet locally, either through a church or community center.

Don’t forget to tell the people around you what’s going on – and to ask for help when you need it. It’s up to you who you tell and when, but the more you share with family and friends, the better equipped they’ll be to lend a hand when you need it.

While triple-negative breast cancer is a more serious type of breast cancer, there are plenty of ways to treat it, from chemotherapy to immunotherapy. The more you know about the cancer, the better prepared you'll feel throughout treatment, too, so understanding your cancer stage will be helpful as you work with your health care team. Don't be afraid to ask your doctor questions about parts of your care – from treatment suggestions to the status of the cancer spread and stage – to make sure you feel comfortable throughout the process.

What is the triple-negative breast cancer survival rate?

This will mostly depend on your unique situation, so ask your health care team what to expect for the best information. But the American Cancer Society lists overall cancer survival rates based on stages at diagnosis:

  • Local or stage 0-stage I: 5 years after diagnosis, more than 90% of people were alive.
  • Regional or stage II-stage III: 5 years after diagnosis, more than 60% of people were alive.
  • Distant or stage IV: 5 years after diagnosis, more than 10% of people were alive.
  • All stages combined: 5 years after diagnosis, 77% of people were alive.

Can you fully recover from triple-negative breast cancer?

This varies from person to person and also depends on whether the goal of your treatment is to get rid of the breast cancer or to keep it from growing and spreading. With immunotherapy and some newer drugs, doctors are seeing higher cure rates for those with early-stage breast cancer. 

Overall, about 60% of people with triple-negative breast cancer will survive more than 5 years without disease, but 4 out of 10 women will have it come back quickly. 

Is triple-negative breast cancer aggressive?

Yes. Because TNBC grows and spreads more quickly than other kinds of breast cancer, it's considered more aggressive. 

How quickly does triple-negative breast cancer spread?

Quicker than other breast cancers. For instance, in one study, triple-negative breast cancer tumors grew by 1% each day from the time of diagnosis to surgery, whereas HER2-positive breast cancer tumors grew 0.859% each day.

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