The most common type of breast cancer is hormone receptor-positive, HER2-negative, often shortened to HR+/HER2-. That means that the sex hormones estrogen, progesterone, or both help the cancer grow, but the tumor cells don’t have an unusual amount of receptors for a protein called human epidermal growth factor.
If you’ve been diagnosed with this type of cancer, the treatment options can seem overwhelming. Your doctor can guide you in choosing the plan that will work best for you. Many things go into the decision, including the cancer stage, your overall health, and traits of the cancer cells.
Treatments are available that are personalized to work against the exact type of cancer you have, helping you live longer or recover completely. Here’s what you need to know.
Which Therapies Specifically Treat HR+/HER2- Breast Cancer?
Several kinds of systemic therapies treat HR+/HER2- breast cancer by denying tumor cells the things they need to survive.
Endocrine (hormone) therapy cuts off the supply of hormones or blocks cells’ ability to use them. Drugs called kinase inhibitors disrupt the transmission of growth signals to cancer cells. Biologics are made from living cells and fight cancer in multiple ways.
Drugs specifically used to treat HR+/HER2- breast cancer include:
These medications work differently and can cause different side effects. They may be the first treatment you’re prescribed, or they may come after surgery or after other treatments have stopped working. They’re often used along with each other or with other therapies.
What Is Endocrine Therapy?
This is also called hormone therapy. It can be used to treat all stages of HR+/HER2- breast cancer, most often after surgery to lower the chances that the cancer will come back. Sometimes it’s given before surgery to try to shrink a large tumor so it’s easier to remove. It can also help control breast cancer that has spread to other parts of your body (metastasized).
With early-stage HR+ breast cancer, doctors usually recommend you have some form of endocrine therapy for at least 5 years. With stage IV cancer, cancer that gets worse during treatment, or cancer that comes back after treatment, endocrine therapy can be used long-term, as long as it continues to be helpful.
Several classes of drugs are used in endocrine therapy. Which one you’ll get depends on whether you’ve been through menopause and which other drugs you’ve tried.
- Selective estrogen receptor modulators (SERMs) and selective estrogen receptor degraders (SERDs) block estrogen from attaching to receptors on cancer cells.
- Aromatase inhibitors block fat cells and other tissues from making estrogen.
- Luteinizing hormone-releasing hormone (LHRH) agonists stop your ovaries from making estrogen.
These drugs are given either as a pill or a shot.
Surgery to remove your ovaries (bilateral oophorectomy) is another way to lower the amount of estrogen your body makes. It can be part of HR+/HER2- breast cancer treatment, or it can be done to lower your risk of both breast and ovarian cancer if you have a mutation in the BRCA1 or BRCA2 genes.
Learn more about endocrine therapy for HR+/HER2- breast cancer.
What Are Kinase Inhibitors?
Kinase inhibitors treat HR+/HER2- breast cancer by blocking the action of certain proteins called kinases that send signals to cancer cells telling them to grow and spread. They’re a type of targeted therapy, which means they’re designed to act only on cancer cells rather than healthy cells.
Different drugs work against different kinases. To decide if one might work well for you, your doctor will test your tumor cells to see if they have a protein defect that allows them to grow out of control.
They’re most often used to treat metastatic breast cancer, usually along with endocrine therapy. You may get a kinase inhibitor as part of your early treatment, or one may be added on if the cancer progresses while you’re taking an endocrine therapy drug by itself. Some kinase inhibitors are only used if other treatments don’t work.
You can take one of these drugs for as long as it keeps the cancer from getting worse and you’re able to manage the side effects. They come in pill form, either tablets or capsules.
Learn more about kinase inhibitors for HR+/HER2- breast cancer.
What Are Biologics?
Biologic drugs are created using living cells. These cells can come from plants, microorganisms, or even your own body. Some of these drugs can be used in certain cases to treat breast cancer that is advanced.
Immunotherapy. Biologic drugs can weaponize your own immune system in fighting cancer – either by strengthening it or helping it identify cancer cells as invaders. A kind of immunotherapy drug called a checkpoint inhibitor blocks a protein that acts like a brake on certain immune cells.
Dostarlimab (Jemperli) is sometimes used in treating HR+/HER2- breast cancer if tests on the tumor cells show a gene problem called a mismatch repair deficiency (dMMR). It’s for people who have stage IV cancer and don’t have other treatment options.
Antibody-drug conjugate. This type of medication combines a manufactured immune system protein called a monoclonal antibody and a chemotherapy medication. The antibody seeks out and attaches to a specific target on a cancer cell. That delivers chemo directly to tumor cells rather than healthy cells.
Sacituzumab govitecan (Trodelvy) is an antibody-drug conjugate that’s approved to treat stage IV HR+/HER2- breast cancer in people who’ve already tried endocrine therapy and two other kinds of treatment. It’s an IV you get once a week for 2 weeks, then a week off, for as long as it keeps helping you. Side effects are similar to those of other types of chemotherapy, such as nausea, fatigue, and hair loss.
Fam-trastuzumab deruxtecan (Enhertu), which is also an antibody-drug conjugate, is approved for HER2-positive, HER2-low, and HER2-ultra low, but not HER2-negative breast cancer. Your doctor might prescribe it if you’ve already tried chemotherapy, hormonal therapy, or an anti-HER2 medication before. It’s given as an IV every three weeks unless the cancer grows. Similar to most breast cancer medications, some of the most common side effects include constipation, vomiting, hair loss, and fatigue.
Enhertu has two main parts, including fam-trastuzumab, the antibody part, which stops the HER2 protein from getting signals to grow, and a chemotherapy part called DXd, which works to keep the cell from growing and dividing.
HER2-low and HER2-ultra low used to be classified as HER2-negative breast cancer. HER2-low has IHC scores of 1 or 2; HER2-ultra low has a score of 0 (same as HER2-negative). HER2-low and HER2-ultra low are now separate categories. Some experts think of them as being a subcategory of HER2-negative – especially if the score is IHC 1 – because the conditions have many similarities.
Learn more about biologics for HR+ breast cancer.
5 Things to Consider When Planning Your Treatment
You have a lot to think about, whether you’ve just been diagnosed with HR+/HER2- breast cancer or you’re already getting treatment and considering a change. Your doctor can guide you, but some decisions only you can make. Here are five things to consider:
Your treatment options. The range of treatment options may seem overwhelming. But not all are right for everyone. Your doctor can explain them and make recommendations based on expert guidelines. But you shouldn’t hesitate to do your own research and get a second opinion if you want one.
Your unique situation. You’ll have tests done on the cancer cells to see which treatments could help. Some medications only work if tumor cells have certain weaknesses. Others are only approved to be used with cancer at a specific stage. Your doctor can help you understand those test results.
Relative effectiveness. Some treatments work better for certain people than for others. Ask your doctor about the results of clinical trials and what they mean for you.
Quality-of-life questions. These-cutting edge treatments can keep cancer from coming back after surgery, or help you live longer. But they can have unpleasant or even dangerous side effects. You’ll need to consider whether the benefits to you outweigh the risks.
Cost. Some medications are new and may cost many thousands of dollars a month. Others have been around for a long time and are available in a less-expensive generic version. In some cases, insurance companies may require you to try treatments in a certain order. It’s important to work with your insurance company to understand your coverage and out-of-pocket costs.