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Are you wondering if you should be taking hormonal therapy for breast cancer? Read on to learn about when hormonal therapy is used.
Hormonal therapy is recommended if the breast cancer you have is hormone receptor positive (HR+). Hormonal therapy may be part of your treatment plan if you have ductal carcinoma in situ (DCIS), early stage breast cancer, and advanced breast cancer. Hormonal therapy is also used in certain people at high risk of developing breast cancer. The key thing about hormonal therapy is that it only works for receptor-positive breast cancer cells.
What do hormones have to do with breast cancer?
What do hormones have to do with breast cancer? We are interested in hormones because some types of breast cancers are fueled by hormones called estrogen and progesterone. When estrogen or progesterone bind to receptors on the breast cancer cell, they may help the breast cancer to grow. Treatment that stops hormones from binding to receptors on the breast cancer cells is called hormonal therapy. Hormonal therapy is also referred to as endocrine therapy.
What hormone receptors are on breast cancer cells?
There are two main types of hormone receptors on breast cancer cells, which are:
- Estrogen receptors
- Progesterone receptors
There are different ways to denote breast cancers based on the hormone receptors.
- Breast cancers that have estrogen receptors are called ER-positive (ER+)
- Breast cancers that have progesterone receptors are called PR-positive (PR+)
- Breast cancers that have estrogen or progesterone receptors, or both, are called hormone receptor-positive (HR+)
Likewise, if the breast cancer does not have estrogen or progesterone receptors, it is called hormone receptor-negative breast cancer.
Breast cancer may have different combinations of positive or negative receptors. For example, if someone’s breast cancer is estrogen receptor positive and progesterone receptor negative, we would call this “ER-positive/PR-negative” (ER+/PR-).
What hormonal therapy is available?
There are two types of hormonal therapy that you will hear about.
- Drugs that block the estrogen receptor (antiestrogens). Tamoxifen is the most common antiestrogen drug. It is a pill that is usually taken once a day. It has been used for many years for the treatment of breast cancer. Antiestrogens can be used in both pre-menopausal and post-menopausal women. Fulvestrant (Faslodex) is also directed against the estrogen receptor. This medication is given in people with advanced breast cancer.
- Drugs that block the estrogen from being made (aromatase inhibitors). There are 3 different aromatase inhibitors available. These are anastrozole, exemestane, and letrozole. They are all equally effective. All of the aromatase inhibitors are pills and usually taken once a day. Aromatase inhibitors are used in people who do not have working ovaries.
You should expect to be on hormonal therapy for 5 to 10 years.
Some people may experience side effects such as hot flashes and vaginal dryness. Over the long term, people who are taking aromatase inhibitors may get bone thinning because the body is receiving less estrogen.
Talk to your medical team if you have any problems or questions with your medicines. Keep in mind that these side effects can usually be managed.
For more details about hormonal therapy, be sure to check out this previous article about hormonal therapy to learn about hormonal drugs.
Who should get hormonal therapy?
Generally, hormonal therapy is used in four types of people.
- People who have been diagnosed with ductal carcinoma in situ
- People with early stage breast cancer
- People with advanced breast cancer
- People who have a high risk of developing breast cancer
Ductal Carcinoma in Situ
Ductal carcinoma in situ (DCIS) is non-invasive breast cancer. For the most part, hormonal therapy is a choice. Hormonal therapy does not improve survival after surgery (and radiation therapy in some people) in people with DCIS.
- After breast conserving surgery (lumpectomy), hormonal therapy will decrease the risk of the cancer coming back in the breast that had the DCIS.
- If you did not have radiation therapy after breast conserving surgery (lumpectomy), hormonal therapy is recommended more strongly.
- If the DCIS was estrogen receptor-positive, hormonal therapy is more likely to help you than if the DCIS was estrogen receptor-negative.
Can I skip hormonal therapy in DCIS?
The short answer is yes. The benefit of hormonal therapy is to decrease the risk of the cancer returning in the breast. If you have had a mastectomy, there is therefore minimal benefit of taking hormonal therapy.
If you have side effects after being on hormonal therapy for 6 months, you may want to talk about whether or not you should keep taking it..
Hormonal therapy is not necessary if you have had a bilateral mastectomy (removal of both breasts) for DCIS.
Early Stage Breast Cancer
The typical treatment steps in early stage breast cancer (Stages I, II and III) include surgery, and, in some people, radiation, chemotherapy, targeted therapy, and hormonal therapy. Just like in DCIS, hormonal therapy is given only for hormone receptor-positive breast cancers.
Hormonal therapy is recommended
- After surgery. Hormonal therapy is recommended after surgery to decrease the risk of recurrence. Recurrence means that the cancer has come back in the breast, neighboring lymph nodes, or other parts of the body.
- Before surgery. Hormonal therapy may be recommended before a surgery in order to make the tumor smaller and decrease the extent of the surgery.
Hormonal therapy in early-stage breast cancer is a cornerstone of your treatment plan. Some people think that hormonal therapy is “icing on the cake” and not as important as surgery, chemotherapy, radiation therapy, and targeted therapy. It is important to know that hormonal therapy is one of the most effective treatments for hormone receptor-positive breast cancer.
For example, studies show that when tamoxifen is taken for five years, it significantly reduces the risk of the cancer recurring. It also improves your chances of surviving breast cancer. This means there is less chance of the breast cancer coming back. Finally, taking tamoxifen for the full 5 years is more effective than taking it for only 1-2 years.3
One of the most common reasons that people stop taking hormonal therapy is because of side effects. Hormonal therapy may cause hot flashes, vaginal dryness, vaginal discharge, leg cramps, muscle pains or joint pains.
Talk with your medical team if you develop symptoms and make sure to tell them if the side effects are severe enough that you are thinking about stopping the medication. Side effects can be managed and changing to another medication may also help your side effects.
Can I skip hormonal therapy in early-stage breast cancer?
It depends. Sometimes, hormonal therapy is skipped if the tumor has a low risk of recurrence. This would mean:
- A tumor that is small (less than 0.5 cm) and has no lymph node involvement.
- A tubular or mucinous carcinoma that is less than 3 cm and has no lymph node involvement.
Advanced Disease
Advanced breast cancer (metastatic disease or Stage IV) is when the breast cancer has spread to other parts of the body.
For advanced breast cancer, the first-line treatment options are chemotherapy or hormonal therapy. Hormonal therapy can be given only for receptor positive (HR+) breast cancers. It can be given with or without targeted therapy.
Because hormonal therapy is generally better tolerated than chemotherapy, most people prefer hormonal therapy to chemotherapy in the treatment of advanced disease. This does not mean that hormonal therapy is without side effects. Your medical team will talk to you about possible side effects and how to manage any side effects you may get.
In addition to antiestrogens and aromatase inhibitors, there are other hormonal therapies that can be used in people with advanced breast cancer.
Breast Cancer Prevention
Hormonal therapy can reduce the risk of developing breast cancer in people who are at high risk of breast cancer. Studies have shown that taking hormonal therapy for 5 years helps to reduce the risk of breast cancer developing by 30 to 50%.
The decision to take hormonal therapy needs to take into account the pros and cons. Many women who are on hormonal therapy for breast cancer prevention have a decrease in the number of biopsies they have.
These are topics to discuss with your medical team. Your primary care provider or other doctor, such as a gynecologist, can prescribe hormonal therapy to decrease the risk of your developing breast cancer.
References
- NCCN Clinical Practice Guidelines in Oncology. Breast Cancer. National Comprehensive Cancer Network. Available at http://www.nccn.org/professionals/physician_gls/pdf/breast.pdf. Version 2.2019
- Effects of chemotherapy and hormonal therapy for early breast cancer on recurrence and 15-year survival: an overview of the randomised trials. The Lancet. 2005;365(9472):1687-1717. doi:10.1016/s0140-6736(05)66544-0
- Nelson H, Fu R, Zakher B, Pappas M, McDonagh M. Medication use for the risk reduction of primary breast cancer in women. JAMA. 2019;322(9):868. doi:10.1001/jama.2019.5780
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