Triple-negative breast cancer accounts for 10–15% of all breast cancer cases. New treatments may increase the chance of curing the cancer or improving a person’s outlook.

Breast cancer takes different forms. It can be hormone receptor-positive or hormone receptor-negative, depending on whether the cancer cells have estrogen or progesterone receptors.

Breast cancer cells can also be positive or negative for the human epidermal growth factor (HER2) protein.

Triple-negative breast cancer (TNBC), which occurs in 10–15% of breast cancers, involves cancer cells that are negative for hormones and the HER2 protein. In other words, the cancer cells do not have receptors for:

  • estrogen
  • progesterone
  • HER2

The lack of receptors on the cancer can make it more difficult to treat, as therapies that target the receptors are not effective.

According to the American Cancer Society, high risk groups include women who:

  • are under the age of 40 years
  • are of African American descent
  • have a BRCA1 gene mutation

TNBC can grow more quickly than other cancers and has a higher rate of recurrence.

“There are a lack of targets and some drug resistance,” Dr. Jack Jacoub, the medical director of the Memorial Care Cancer Institute at Orange Coast Medical Center in Fountain Valley, California, told Medical News Today.

“There are so many pathways going on in the cancer cell,” he added, “and we can’t manipulate it the way we can with HER2 and other types of breast cancer.”

Researchers are developing new treatments that work for TNBC.

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According to the Centers for Disease Control and Prevention (CDC), treatment options for TNBC include:

  • lumpectomy (the removal of the tumor while leaving most of the breast intact)
  • mastectomy (the removal of the breast and some surrounding tissue)
  • chemotherapy
  • radiation therapy

TNBC is more responsive to immunotherapy than other forms of breast cancer. Immunotherapy helps the immune system find and attack the cancer cells.

People commonly use pembrolizumab, a monoclonal antibody medication, to treat TNBC. Trodelvy (sacituzumab govitecan-hziy) is also an antibody drug that the Food and Drug Administration (FDA) has approved for the treatment of TNBC.

Dr. Xinyu Nan, a medical oncologist with the Center for Cancer Prevention and Treatment at the Providence St. Joseph Hospital in Orange County, California, told MNT that antibody-drug conjugates are effective at targeting the cancer.

Antibody-drug conjugates contain an antibody linked to a small molecule drug that is toxic to the tumor cell.

The antibody-drug conjugate delivers a molecule through an intravenous line that attaches to the cancer cells. These molecules help the chemotherapy better target the cancer cells.

According to Dr. Crystal Fancher, the lack of receptors to target means that some treatments for other forms of breast cancer are not effective for TNBC.

Dr. Fancher is a surgical breast oncologist at the Margie Petersen Breast Center at Providence Saint John’s Health Center and an assistant professor of surgery at Saint John’s Cancer Institute, both in Santa Monica, California.

“Unlike other breast cancers that have hormone receptors, like HER2, triple-negative is harder to treat,” she told MNT.

Dr. Jacoub explained that people’s outcomes tend to improve when they receive chemotherapy in combination with other treatments. A course of treatment now typically includes “immunotherapeutics, which we use before and after surgery as well as during a recurrence,” he added.

Platinum chemotherapy, or chemotherapy using platinum-based drugs, is common in the treatment of TNBC due to its effectiveness. However, research has shown that severe side effects can limit its use.

One 2018 review noted 40 specific side effects, including a decrease in bone marrow production, problems with kidney function, headaches, and other negative effects on the nervous system. Some treatments are available to address these side effects.

Dr. Nan estimated that about 40% of people can use a combination of immunotherapy and chemotherapy.

There are several new and ongoing studies looking at treatments for TNBC.

Dr. Fancher encouraged people with TNBC to look into trials.

“Research on clinical trials is really important,” she told MNT. “If you [have] triple-negative breast cancer, consider a clinical trial. It helps move the research forward. There are lots of trials out there, and many are having good results.”

New antibody-drug conjugates (ADCs)

Two antibody medications are in the later stages of development and close to gaining approval to treat TNBC: datopotomab deruxtecan (Dato-DXd) and trastuzumab duocarmazine.

In a small 2023 study with 44 participants who took Dato-DXd for TNBC, 32% saw their tumors shrink, while 80% had their disease under control.

Additionally, in one small study cited in a 2022 review, 28% of participants with certain types of breast cancer responded positively to trastuzumab duocarmazine, and 40% of those with a different type of cancer also had positive results.

Importantly, healthcare professionals need to be aware that novel ADCs have associations with unique and, in some cases, serious toxicities.

TVEC (talimogene laherparepvec)

In a clinical trial at the Moffitt Cancer Center in Florida, researchers merged neoadjuvant chemotherapy with the application of a virus that can kill cancer cells — an “oncolytic virus” — called TVEC (talimogene laherparepvec).

They found that 45.9% of participants had a good response to this treatment, with little to no cancer remaining (RCB0 rate), and 65% had a positive response (RCB0-1 rate).

cSNX1.3

Researchers from the University of Arizona have developed a drug called cSNX1.3, which specifically targets TNBC.

Developed using epidermal growth factor receptor (EGFR) technology, the drug reportedly causes few or no toxic side effects.

Researchers conducted the study on mice and are now working toward FDA approval to test the drug in a phase 1 clinical trial in humans.

Cardamonin

In 2022, Dr. Patricia Mendonca, an assistant professor and research analyst from Florida A&M University in Tallahassee, Florida, delivered a presentation to showcase findings suggesting that cardamonin can reduce the growth of cancer cells in people with TNBC (in a dose-dependent manner).

Cardamonin is a natural compound found in cardamom and various plants from the Zingiberaceae (ginger) family.

Clinical trials

People who are interested in learning more or potentially joining a clinical trial can look at ClinicalTrials.gov. At any time, there are likely several ongoing or recruiting studies across the country. Details about signing up or getting more information on TNBC clinical trials are available here.

A person should talk with their doctor before joining a clinical trial. A doctor may be able to help the person find a relevant study or recommend ones that will work best for them.

TNBC is curable when a doctor diagnoses it during the first three stages (1–3), said Dr. Jacoub. He treats stages 1–3 with everything he can in order to remove and destroy the cancer.

However, TNBC is less likely to be curable if it recurs or spreads past the lymph nodes. TNBC is the most likely form of breast cancer to recur.

The outlook for people with localized TNBC over a 5-year period is good. Around 91% of people will survive to the 5-year mark.

However, if the cancer spreads to local tissue or lymph nodes, the 5-year survival rate drops to 66%. And if it spreads to other organs or tissue, that rate falls to 12%.

These figures are based on data for people who received treatment in the past. Newer methods have changed the outlook, which will continue to shift as different treatments become available.

Anecdotally, Dr. Nan has a segment of patients who have responded to immunotherapy treatment for longer than 5 years.

“Maybe if [his practice] follows these [people] long enough, some may still be alive after more than 10 or 15 years, then we can say [their cancer is] cured,” he said. “With developed or newer types of immunotherapy, [we] may be able to cure stage 4 cancer in the future.”

Dr. Jacoub agreed that the outlook is changing with newer treatments. He also noted that although some people have a reduced quality of life while undergoing treatment, others can maintain a good quality of life.

Below are some commonly asked questions about TNBC.

What is the most common treatment for triple-negative breast cancer?

Chemotherapy is the most common treatment for TNBC. Chemotherapy drugs that doctors commonly use to treat TNBC include anthracyclines, taxanes, capecitabine, gemcitabine, and eribulin. Doctors also commonly use pembrolizumab, an immunotherapy treatment, alongside chemotherapy.

What is the life expectancy of triple-negative breast cancer?

Around 91% of people with localized TNBC will survive to the 5-year mark. If the cancer spreads to local tissue or lymph nodes, this rate drops to 66%. If it spreads to other organs or tissues, the rate falls to 12%.

TNBC is an aggressive form of breast cancer that may not respond to treatments that are effective against other forms of breast cancer.

With early detection and aggressive treatment, doctors may be able to cure TNBC. When a doctor diagnoses TNBC after it has spread, there is no current cure, but some treatments can help a person live longer with a better quality of life.

People with TNBC should try to find a doctor who is up to date on the latest treatments or can identify new clinical trials that may help.