Which Medications Are Used to Treat Breast Cancer?

Breast cancer is the second most common type of cancer in the U.S. for women. Over the decades, pharmaceutical companies, researchers, and other groups have invested time, effort, and money into developing many breast cancer treatment options. 

Compared to the first breast cancer surgery performed all the way back in 1882, today there are several tools and strategies that cancer specialists can choose from to treat breast cancer. In addition to surgery and radiation therapy (RT), there are a large number of FDA-approved medications that can help prevent or treat breast cancer. 

But, with so many medications available today, it can be hard to keep track of the different ones that are available. 

In this article, we’ll list out and briefly describe different medications that can be used to prevent or treat breast cancer. 

How is breast cancer treated?

Cancer is complicated. Breast cancer treatments are unfortunately no exception. Depending on the type, severity, and other characteristics of someone’s cancer, an overall treatment strategy can change. 

But, no matter the specifics, breast cancer is usually treated with surgery, RT, and/or medications. 

• Surgery: Many people with non-metastatic breast cancer undergo surgery to remove their tumor (cancer). There are different types of breast cancer surgery, including surgeries that can remove part of the breast or the entire breast. RT and medications — both mentioned below — can be used before or after surgery to improve the chances of successfully treating a tumor.

• Radiation: RT uses energy — from sources like x-rays and gamma rays — to shrink tumors and kill cancer cells. 

• Chemotherapy: Chemotherapy medications are anti-cancer treatments that directly fight and kill cancer cells. Not every person with breast cancer needs chemotherapy, but it’s one of the most common forms of treatment. Although it’s often effective, it can cause a lot of side effects. 

• Hormone (endocrine) therapy: In many cases, breast cancer can be especially sensitive to the amount of estrogen and progesterone in the body. These natural hormones can act as fuel for a tumor and cause the cancer to grow. Hormone therapy medications work to block estrogen or progesterone to help control this growth. 

• Targeted therapy: Targeted therapy medications work by seeking out specific molecules or genes that are thought to be involved in the growth and spread of cancer. 

• Immunotherapy: Ultimately, a functioning immune system is a key component of keeping us healthy. But, the immune system sometimes needs a boost so it can more effectively fight cancer. Immunotherapy medications — technically a type of targeted therapy — can help strengthen our immune system’s response to cancer. 

• Supportive care: Cancer — and different treatments used to treat cancer — can cause quite a few side effects. Supportive care treatments help control how bad cancer-related symptoms are. Medications used to control nausea, pain, or anxiety are examples of supportive care treatments. These aren’t specifically discussed in this article. 

What is the best medication for treating breast cancer?

Spoiler alert — there isn’t one best medication for treating breast cancer. Depending on the severity and type of breast cancer, many medications can be used. Sometimes only one medication is needed, but often, multiple medications are used. 

Selecting medication(s) to treat breast cancer is a very variable decision based on your situation — your cancer specialist can tell you what option(s) may be best for you. But, it’s likely that they may choose from one or more of the options discussed next. 

Of note, only single-ingredient medications are mentioned in the tables below. Several of the medications are also available as combination products. 

Chemotherapy medication options

Chemotherapy is often used before surgery to shrink a tumor, after surgery to kill cancer cells that were potentially left behind after a tumor removal, or to treat more advanced forms of breast cancer. Chemotherapy can be used alone or in combination with RT, other chemotherapies, or other cancer medications. 

Chemotherapy is typically given at a hospital or a cancer center, and usually infused into a vein. Although these medications are used for a reason — they’re often effective — they can cause a number of harmful side effects. 

Like mentioned, chemotherapy medications work by targeting cancer cells directly. But, they don’t know to only target cancer cells. Unfortunately, they’re potentially harmful because they can also affect normal parts of our bodies, such as our hair, mouth, and internal organs. 

Chemotherapy medications used to treat breast cancer are discussed in a recent GoodRx article. To learn more, click or tap here. 

Targeted therapy medication options

Chemotherapy was the first category of breast cancer medications, and many people still think of it as the best or only treatment option. But there are actually a number of other cancer medications that aren’t chemotherapy.  

As the years have gone on, researchers’ main focus has shifted from chemotherapy to targeted therapy. Many cancers can be caused by genetic mutations or an excessive growth of certain proteins, so if these changes are directly targeted, it’s thought that there may be a better chance for a successful treatment. 

FDA-approved targeted therapies for breast cancer are mentioned in the table below. Some of these medications — especially infusion-based medications — are only given at a hospital or cancer center. Others can be dispensed at a specialty pharmacy or retail pharmacy.  

A cancer specialist can run lab or genetic tests to determine if breast cancer may respond to one or more of the targets mentioned above. 

Immunotherapy medication options

Many people think of immunotherapy, or immune targeted therapy, as a unique type of cancer treatment. But, it’s technically a type of targeted therapy. 

Regardless of how they’re classified, immunotherapy medications help strengthen — or empower — the immune system to more effectively fight cancer. These medications are often used in addition to chemotherapy, but they can also be used by themselves. 

Are there any other medications that treat breast cancer?

In addition to chemotherapy, targeted therapy, and immunotherapy, there are other medications that can be used to treat breast cancer. 

Like mentioned, many breast cancers are sensitive to estrogen or progesterone. Estrogen is a common fuel source for breast cancer cells, so hormonal therapy medications can cut off this fuel source by lowering the amount of estrogen in the body. Some hormonal therapies are specifically intended for people who have gone through menopause, while others are not. 

Also, when breast cancer spreads (metastasizes), it can go to other parts of the body, most commonly the bones. Some medications can help prevent bone loss and treat bone metastases. 

Can any medications help prevent breast cancer?

There are two medications that can help lower the chances of developing breast cancer. These two medications — raloxifene (Evista) and tamoxifen — can help lower the risk by up to 40%, depending on your situation. 

Raloxifene and tamoxifen work in a unique way — they act like estrogen in some areas of the body, but they stop estrogen from working in other areas of the body. They can stop estrogen from getting to breast tissue and this can lower the risk of developing breast cancer.  

How long do you have to take medication for breast cancer?

Unfortunately, there’s not a great answer for this. It’s highly dependent on the situation. Some medications are taken for just a few months, and others may be taken for up to 10 years. 

For example, chemotherapy is usually given in rounds (cycles). One cycle often lasts one month, but it can be shorter or longer depending on the person and medications being used. Sometimes cycles are prescribed for a set time frame — such as 6 cycles lasting for 6 months — but sometimes they’re given indefinitely until the medication(s) stop working.   

By comparison, hormonal therapies — like tamoxifen, anastrozole, and exemestane — may be given for up to 5 to 10 years. 

There are some general considerations about when you may stop taking a particular medication or switch to another one. These may include: 

• If your cancer has worsened or progressed

• If your treatment is determined to be ineffective by your cancer specialist

• If the costs of a medication outweigh its potential benefits 

• If side effects are too bothersome or severe and outweigh its potential benefits

What are some common side effects of breast cancer medications?

Depending on the medications, side effects differ considerably. While specific medications have their own unique side effects, there are also general side effects that are commonly seen among groups of cancer medications.

Chemotherapy is widely known for causing side effects. Common side effects of breast cancer chemotherapy may include: 

• Hair loss

• Sores in the mouth and throat

• Loss of appetite

• Fatigue

• Nausea, vomiting, or diarrhea

• Higher chance of getting an infection compared to normal

When targeted therapies were initially being developed, it was thought they might have fewer  side effects than chemotherapy because they more specifically target cancer cells. But, targeted therapies still have many bothersome side effects. These can include:

• Diarrhea

• Liver problems

• Fatigue

• Rashes, dry skin, hair color changes, and other skin problems

• Excessive bleeding

• Hypertension (high blood pressure)

Hormone therapies can also cause side effects, and they often resemble symptoms of menopause. This is because many of them work by lowering the amount of estrogen in the body. 

These are a few possible side effects, but it’s recommended to speak to a pharmacist or cancer specialist to learn more specifics about side effects depending on the medication(s) that you may be receiving. 

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Written by:

Joshua Murdock, PharmD, BCBBS

Joshua Murdock, PharmD, BCBBS, is a licensed pharmacist in Arizona, Colorado, and Rhode Island. He has worked in the pharmacy industry for more than 10 years and currently serves as a pharmacy editor for GoodRx.

Reviewed by:

Sonja Jacobsen, PharmD, BCPS, BCOP

Sonja Jacobsen, PharmD, BCPS, BCOP,  is a clinical oncology pharmacy specialist currently practicing in Seattle. She has been practicing as a pharmacist since 2015 and is licensed to practice in Washington state and North Carolina.

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