What’s New in Breast Cancer Research?

Researchers around the world are working to find better ways to prevent, detect, and treat breast cancer, and to improve the quality of life of patients and survivors.

Breast cancer causes

Studies continue to uncover lifestyle factors and habits, as well as inherited genes, that affect breast cancer risk. Here are a few examples:

  • Several studies are looking at the effect of exercise, weight gain or loss, and diet on risk.
  • Studies on the best use of genetic testing for breast cancer mutations continue.
  • Scientists are exploring how common gene variations (small changes in genes that are not as significant as mutations) may affect breast cancer risk. Gene variants typically have only a modest effect on risk, but when taken together they could possibly have a large impact.
  • Possible environmental causes of breast cancer have also received more attention in recent years. While much of the science on this topic is still in its earliest stages, this is an area of active research.

Reducing breast cancer risk

Researchers continue to look for medicines that might help lower breast cancer risk, especially women who are at high risk.

  • Estrogen blocking drugs are typically used to help treat breast cancer, but some might also help prevent it. Tamoxifen and raloxifene have been used for many years to prevent breast cancer.  More recent studies with another class of drugs called aromatase inhibitors (exemestane and anastrozole) have shown that these drugs are also very effective in preventing breast cancer
  • Other clinical trials are looking at non-hormonal drugs for breast cancer reduction. Drugs of interest include drugs for diabetes like metformin, drugs used to treat blood or bone marrow disorders, like ruxolitinib, and bexarotene, a drug that treats a specific type of T-cell lymphoma.

This type of research takes many years. It might be some time before meaningful results on any of these compounds are available.

New lab tests

Liquid biopsies

Circulating tumor cells (CTCs) and circulating tumor DNA (ctDNA)

Circulating tumor cells (CTCs) are cancer cells that break away from the tumor and move into the bloodstream. Circulating tumor DNA (ctDNA) is DNA that is released into the bloodstream when cancer cells die. Researchers are investigating tests that measure the amount of CTCs and ctDNA in the blood of women with breast cancer. Identifying and testing the CTCs and ctDNA in the blood is sometimes referred to as a “liquid biopsy.” This type of biopsy may offer an easier and less expensive way to test the tumor than a traditional needle biopsy, which comes with risks such as bleeding and infection.

Some studies have shown that in women with metastatic (Stage 4) breast cancer, a high level of CTCs might predict a poorer outcome compared to women with a lower level.   

Although more studies are needed before liquid biopsies could replace the traditional needle biopsy, some potential uses include:

  • Looking for new gene changes (mutations) in the tumor cells that might mean the cancer has become resistant to specific treatments (like aromatase inhibitors)
  • Determining if a certain drug will work on a tumor before trying it
  • Helping decide if a woman’s cancer is responding to a certain treatment by noticing a decline in CTC level
  • Predicting if the breast cancer will recur (come back) in women with early stage breast cancer

New imaging tests

Newer types of tests are being developed for breast imaging. Some of these are already being used in certain situations, while others are still being studied.It will take time to see if they are as good as or better than those used today. Some of these tests include:

  • Scintimammography (molecular breast imaging)
  • Positron emission mammography (PEM)
  • Electrical impedance imaging (EIT)
  • Elastography
  • New types of optical imaging tests

For more on these tests, see Newer and Experimental Breast Imaging Tests. 

Breast cancer treatment


It is known that chemotherapy can be helpful for many breast cancer patients. But predicting who will benefit the most or the least is still being studied. Sometimes there are significant side effects (long- and short-term) from chemotherapy, so having tests that can determine who really needs chemo would be useful. Many studies are being done to evaluate different tests that can more accurately tell which patients would benefit from chemo and which patients could avoid it. 

Triple-negative breast cancer

Since triple-negative breast cancers (TNBC) cannot be treated with hormone therapy or targeted therapy such as HER2 drugs, the treatment options are limited to chemotherapy. And although TNBC tends to respond well to initial chemotherapy, it tends to come back (recur) more frequently than other breast cancers. 

In 2019, the immunotherapy drug Atezolizumab (Tecentriq), was approved along with the chemotherapy drug nab-paclitaxel (Abraxane) for use in women with advanced triple negative breast cancer that makes the PD-L1 protein. Other potential targets for new breast cancer drugs have been identified in recent years. Drugs based on these targets, such as kinase inhibitors, are now being studied to treat triple-negative breast cancers, either by themselves, or in combination with chemotherapy. One example is the AKT inhibitor ipatasertib, which, when used with paclitaxel, shows promising results in treating women with TNBC as the first treatment. Another AKT inhibitor, capivasertib, is also showing encouraging results when given with paclitaxel. 

Androgen receptor inhibitors 

Breast cancer cells are routinely tested for estrogen and progesterone receptors to help determine treatment options. About 60% of breast cancer cells also have receptors for androgens (male hormones). Initial studies in women with breast cancer show some response when using the antiandrogen bicalutamide, to treat TNBC that has the androgen receptor. Bicalutamide is a drug that has been used to treat prostate cancer for many years. More studies in breast cancer are ongoing.

Supportive care

There are trials looking at different medicines to try and improve memory and brain symptoms after chemotherapy. Other studies are evaluating if certain cardiac drugs, known as beta-blockers, can prevent the heart damage sometimes caused by common breast cancer drugs such as doxorubicin and trastuzumab. 

Thinking about taking part in a clinical trial

Clinical trials are carefully controlled research studies that are done to get a closer look at promising new treatments or procedures. Clinical trials are one way to get state-of-the art cancer treatment. In some cases, they may be the only way to get access to newer treatments. They are also the best way for doctors to learn better methods to treat cancer. Still, they are not right for everyone.

If you would like to learn more about clinical trials that might be right for you, start by asking your doctor if your clinic or hospital conducts clinical trials, or see Clinical Trials to learn more.

The American Cancer Society medical and editorial content team

Our team is made up of doctors and oncology certified nurses with deep knowledge of cancer care as well as journalists, editors, and translators with extensive experience in medical writing.

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Last Medical Review: September 18, 2019 Last Revised: September 18, 2019

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