Why Don't Targeted Therapies Work for Triple Negative?

What Makes Triple Negative Different From Other Breast Cancers?

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Being diagnosed with breast cancer is a frightening experience; being diagnosed with triple negative breast cancer (TNBC) carries an additional burden. Currently used targeted therapies, taken for 5 to 10 years following the end of active treatment to reduce the risk of recurrence, are not effective as a treatment for TNBC. Although researchers are working to find a targeted therapy that will help to reduce the risk of recurrence for those diagnosed with TNBC, one does not exist at this time.

What We Know About TNBC

  • Every 30 minutes, a woman in the US is diagnosed with triple negative
  • It tends to be a more aggressive breast cancer
  •  It is more likely to recur and harder to treat because there are no targeted therapies
  •  If it does occur, it tends to do so in the first 5 years following active treatment.
  •  Chemotherapy has proven a successful treatment for most triple negative breast cancers.

How It's Different From Other Breast Cancers

Breast cancer is not one disease. Actually, the term "breast cancer" encompasses several types and subtypes of cancers that occur in the breast; they are diagnosed by whether or not they have receptors that fuel most breast cancers. These receptors include the estrogen receptor, or ER; the progesterone receptor, or PR and the human epidermal growth factor receptor 2, or HER2  

When these receptors are present, they help the cancer treatment team decide how best to treat the specific type of cancer. ER positive breast cancer, PR positive breast cancer and HER2 positive breast cancer, treatment include medications that prevent, slow or stop cancer growth by targeting those receptors. These medications are given following the end of active treatment, which includes surgery, chemotherapy and/or radiation therapy. Drugs such as tamoxifen, and aromatase inhibitors, target the estrogen receptor, the target drug for HER2 is Herceptin.

Triple negative is a breast cancer subtype that does not have any of these three important receptors, which are used as targets for cancer treatment. Its name comes from the fact that it is negative for ER, PR, and HER2 receptors. Because triple negative doesn’t have any of these receptors, this subtype of breast cancer does not respond to tamoxifen and Herceptin.

About 70 percent of breast cancers are ER positive; 15 percent of breast cancers are HER2 positive, and 15 percent of breast cancers are triple negative.


TNBC is most often treated with a combination of surgery followed by radiation and/or chemotherapy. Surgical options are the same as for other breast cancers. Lumpectomy plus radiation therapy may be a choice based on the size and location of the tumor.

Several factors may make a mastectomy the better surgical choice with or without breast reconstruction. If a woman has a large tumor, it may require being treated with chemotherapy prior to surgery. Chemotherapy, usually given following surgery, continues to be a very effective treatment for most TNBC.

Breast Cancer Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

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TNBC New Treatment Research

There continues to be ongoing research to identify new treatments. Marc Hurlbert, PhD, Chief Mission Officer for the Breast Cancer Research Foundation, says, “The BCRF research portfolio into new treatments includes several specific studies for new TNBC treatments. One such study involves testing PARP inhibitors in combinations with other drugs in TNBC.”


In a word, no, triple negative cannot be prevented. At this time, no breast cancer can be prevented. There are things that can be done to lower the risk of getting a breast cancer, such as maintaining a healthy weight, exercising regularly, follow a plant-based diet, watch sugar intake, keep alcohol consumption to a minimum and avoid saturated fats.

Even when maintaining a healthy lifestyle, the best thing you can do for yourself is practice early detection, which can lead to finding breast cancer at an early stage when it is easier to treat.

Know your family history of breast cancer, discuss it with your physician or gynecologist and, if there is breast cancer in the family, follow your physician’s advice for screenings.

Since 85 percent of breast cancers occur in women who have no known history of the disease, it is a good idea to start screening at age 40. Despite the recent changes about when to get your first mammogram and scheduling regular mammograms after that, know that mammograms and self-breast exams play an important part in early detection.

A Word From Verywell

If you are diagnosed with triple negative breast cancer, you need to seek treatment from physicians who specialize in breast cancer and regularly treat women who also have been diagnosed with triple negative breast cancer. Your breasts need a thorough evaluation and you need to know all of your treatment options before beginning treatment. If you are under 60 years old, your medical oncologist will want you to have genetic testing to determine if you are a BRCA mutation carrier, as some treatments may be more effective for you.

It is important to have someone accompany you to meet with your surgeon and your oncologist and any other treatment provider. Functioning as a second pair of ears, this person needs to write complete descriptions of what the physician is explaining to you about what triple negative is; your treatment options and why these are your options. Initially, triple negative may be difficult to understand, especially given your stress level. You will be glad to have notes to review following each meeting.

Don’t hesitate to ask as many questions of your treatment team as it takes for you to understand your treatment plan. Get a second opinion from another physician who has extensive experience in treating patients with triple negative breast cancer.

Reach out to organizations that have information, programs, and support services for those dealing with triple negative, such as:

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