Some people may be surprised to learn that some of the treatments for breast cancer can induce an early menopause. Chemotherapy and endocrine therapy change the body’s hormone levels, which can cause menopausal symptoms.
For some people, this effect is temporary and goes away after treatment ends. For those who have already been through menopause, hormonal treatments may cause some symptoms that mimic those of menopause.
Learning that you may experience menopause symptoms while undergoing breast cancer treatment can be overwhelming. Support from your medical team and loved ones can help you care for yourself along the way.
In this post, we’ll discuss why this happens and how you can work with your healthcare team to manage your symptoms.
First, what is menopause?
Menopause affects people who have ovaries. When someone is in menopause, they no longer have menstrual periods, and their ovaries have stopped releasing eggs into the fallopian tubes. Menopause signals the end of a person’s reproductive years. People are considered to have entered menopause after they have not had a menstrual period for 12 months. 1
Ovaries produce the hormones estrogen and progesterone. These hormones control menstruation. Menstrual periods stop during menopause because the ovaries stop producing high levels of these hormones. 1
We describe the periods of time before, during, and after menopause in four stages. We’ll talk more about each of these stages below.
If you have regular menstrual periods, you are in the stage known as premenopause. In premenopause, the ovaries are the main source of estrogen and progesterone in your body. 2
People who have functioning ovaries but do not have menstrual periods due to a medical condition or other reasons such as some contraceptive methods are considered premenopausal.
Perimenopause (menopausal transition)
The menopausal transition is when your body shifts from premenopause to menopause. People often enter the menopausal transition between ages 45 and 55. Perimenopause generally lasts about seven years, but this period may be longer for some. 3
During this time, your ovaries gradually produce less estrogen. Your menstrual periods may become less regular, and you might notice that they are heavier or lighter than usual. 1
In addition to affecting your menstrual cycle, changing hormone levels can cause uncomfortable symptoms. These symptoms may occur during the last one to two years of menopause when there is a more dramatic drop in estrogen levels. 1
The menopausal transition looks different for everyone. Some people have many symptoms, while others may not have any.
Symptoms experienced during the perimenopausal period may include: 1
- hot flashes or flushes
- night sweats
- vaginal dryness
- decreased sex drive (libido)
- difficulty sleeping
- muscle and joint aches
- mood changes
- difficulty concentrating
Your care team can help you find ways to control any uncomfortable symptoms. We’ll discuss this more below.
You reach menopause after you have not had a menstrual period for 12 months unless there is another reason for lack of menstruation such as an intrauterine device or other underlying medical cause.
Blood tests can help determine whether or not you are in menopause if there is any question about your menopausal status.
After you’ve been through menopause, the rest of your life is known as postmenopause. During postmenopause, uncomfortable symptoms may let up or go away entirely. 4
Lower estrogen levels in the body during postmenopause are associated with loss of the protection against two causes of disease. The first is that the lower levels of estrogen lead to loss of bone mineral density—your bones become lighter. This can increase your risk of bone fractures. 4 Ask your doctor about what you can do to strengthen your bones.
Estrogen helps us control our cholesterol levels and improves blood flow.5 Due to the lower estrogen levels during postmenopause, the risk of heart disease increases.4 Talk to your doctor about what you can do to protect your heart.
What is the relationship between breast cancer treatment and menopause?
Some of the breast cancer treatments we use can affect hormone levels. Changes in hormone levels may lead to early menopause in people who have not yet gone through menopause. These changes may also cause people who have already gone through menopause to experience symptoms that resemble going through menopause. 6
Chemotherapy affects rapidly dividing cells. This includes the tissues of the ovary. Chemotherapy can stop ovaries from functioning, causing the transition to menopause. For some people, this change is permanent.
For others, this change is temporary, and their ovaries resume function after they finish chemotherapy. This pause in ovary function during chemotherapy is sometimes called “chemopause.” Ovaries are more likely to resume function after chemotherapy in those under 40 than in those over 40. 7
We don’t always know whether someone is experiencing chemopause or menopause during chemotherapy. The older you are, the more likely it is to be permanent.
Knowing which scenario is happening is important because the medicine we use for endocrine therapy depends on whether the ovaries are functioning. We’ll discuss this in more detail below.
Endocrine therapy is given to patients whose tumors have hormone receptors (HR-positive). When hormones like estrogen or progesterone attach to these receptors, they can help the tumor grow. Therefore, we generally treat people with HR-positive tumors with drugs that block or stop the body from using estrogen. These drugs help stop tumor growth by preventing the hormones from attaching to the receptors.8
Because these drugs affect the body’s estrogen levels, they may cause symptoms of menopause. 6 Tamoxifen may also lead to early menopause by a couple of years.
Your menopausal status may affect what kind of endocrine therapy you receive. 7
A drug called tamoxifen is often used to treat people who are premenopausal at the time of diagnosis.2 Tamoxifen blocks estrogen from binding to the estrogen receptors on tumors and signaling them to grow. 8 It may cause people to miss menstrual periods and experience menopause symptoms without causing early menopause. 7
Drugs called aromatase inhibitors are often used to treat people who have already gone through menopause at the time of diagnosis or in people who are advised to have ovarian suppression (see below). Although the ovaries produce less estrogen than they did before menopause, a protein in the adrenal glands (glands on top of the kidney) and body fat can produce estrogen. This protein is called aromatase. Aromatase inhibitors stop this protein from producing estrogen. 8
Because the estrogen levels in the body are lowered even more, people taking aromatase inhibitors may experience menopause symptoms even though they have already gone through menopause. These symptoms may include hot flashes, vaginal dryness, or joint or bone pain. 8
Ovarian suppression may be used for premenopausal people. This is a medically induced, reversible menopause. It causes the ovaries to produce less estrogen without causing permanent menopause.7 Drugs called luteinizing hormone-releasing hormone (LHRH) agonists block the signal that tells the ovaries to make estrogen. 8 Although they are generally covered by insurance, these drugs can be expensive, and they have to be given by injection.
Some people may have a surgery called oophorectomy to remove their ovaries altogether. This surgery causes immediate and permanent menopause.8 It’s generally a low-risk surgery and is recommended if you are already close to your menopause age or if you have a higher risk of ovarian cancer because you have an inherited gene associated with ovarian
In general, we use LHRH treatment before surgery because the LHRH injections put people into menopause more gradually.
Ovarian suppression or removal allows people who are premenopausal to take the aromatase inhibitors. 8 Recent studies have shown that using an aromatase inhibitor can reduce the risk of cancer recurrence for premenopausal people receiving ovarian suppression, particularly in people with a higher risk of recurrence or in people with advanced breast cancer. 9
Because of the effects that chemotherapy, tamoxifen, or ovarian suppression can have on hormones, people receiving these treatments can miss menstrual periods for 12 consecutive months and still not be in permanent menopause. Blood tests can help us determine whether someone is going through menopause. 7
How can I cope with menopausal symptoms?
Coping with menopause symptoms on top of a breast cancer diagnosis can be difficult emotionally as well as physically. Talking to others about what you are experiencing, such as your loved ones, a counselor, or a support group, can help. Others who have been through this before may be able to offer words of encouragement and tips for managing symptoms. You’re not alone.
Unpleasant menopause symptoms can disrupt your everyday life, making it hard to sleep, focus, or be intimate with someone. Working with your care team can help you find ways to manage these symptoms and improve your quality of life. We suggest taking notes on how you feel daily so that your primary care provider, oncologist, gynecologist, or another care provider can help you find the support you need. They may be able to recommend
medications or non-medication strategies that can help you manage your symptoms.
Hormone replacement therapy and breast cancer
One common menopause treatment used today is hormone replacement therapy. With this therapy, people take medicine that replaces the hormones the ovaries produce less of during menopause. This helps lessen some of the menopause symptoms. However, hormone replacement therapy is not recommended for people who have had breast cancer, even for people with hormone receptor-negative breast cancer. With this type of
cancer, giving someone exogenous estrogen (estrogen from outside the body) could cause the cancer to return. Recent research shows that hormone replacement therapy increases the risk of recurrence for people with a history of breast cancer. 10
Other coping strategies
Some people with breast cancer look to non-hormonal therapies to improve their symptoms. One study showed that acupuncture significantly improved menopause symptoms in breast cancer patients, such as trouble sleeping, depression, headaches, joint pain, headaches, and irritability. 11
Other changes that may also improve your symptoms include:
- exercising regularly (as approved by a doctor), which can improve your mood, sleep, energy, and bone strength
- avoiding alcohol, caffeine, and smoking
- wearing layers of light clothing that you can remove if you experience a hot flash
- breathing or relaxation exercises such as meditation
- getting plenty of sleep and taking naps, if needed
- talking with sexual partners about what you is most comfortable for you
- using a moisturizer or lubricant for vaginal dryness
- making lists, writing yourself notes, or using a calendar to help you keep track of tasks and activities if you find your memory has changed
- doing crosswords or other puzzles that engage your mind 12
- learning a new language to improve cognition
Breast cancer treatments may cause symptoms of menopause by changing the body’s hormone levels. Your care team can recommend medications, lifestyle changes, or other therapies to help you cope with your symptoms. These symptoms are important to manage, so it’s important to get as much information as you can.
1 Menopause: Age, stages, signs, symptoms & treatment. Cleveland Clinic.
https://my.clevelandclinic.org/health/diseases/21841-menopause. Published October 5, 2021. Accessed October 30, 2022.
2 NCNN Guidelines for Patients: Invasive Breast Cancer. National Comprehensive Cancer Network. https://www.nccn.org/patients/guidelines/content/PDF/breast-invasive-
patient.pdf. Published 2022. Accessed August 29, 2022
3 What is menopause? National Institute on Aging. https://www.nia.nih.gov/health/what-menopause. Published September 30, 2021. Accessed October 30, 2022.
4 Postmenopause: Signs, symptoms & what to expect. Cleveland Clinic.
https://my.clevelandclinic.org/health/diseases/21837-postmenopause. Published October 5, 2021. Accessed October 30, 2022.
5 Estrogen & the heart: Risks, benefits & side effects. Cleveland Clinic.
https://my.clevelandclinic.org/health/articles/16979-estrogen–hormones. Published April 29, 2019. Accessed October 30, 2022.
6 Breast cancer and menopausal symptoms. Breast cancer and menopausal symptoms. Cancer Research UK. https://www.cancerresearchuk.org/about-cancer/breast-cancer/living-with/menopausal-symptoms. Published June 14, 2022. Accessed October 30, 2022.
7 NCCN Clinical Practice Guidelines in Oncology: Breast Cancer. National Comprehensive Cancer Network. https://www.nccn.org/loginReturnURL=https://www.nccn.org/professionals/physician_gls/pdf/breast.pdf. Published June 2022. Accessed August 29, 2022.
8 Hormone therapy for breast cancer: Breast cancer treatment. American Cancer Society. https://www.cancer.org/cancer/breast-cancer/treatment/hormone-therapy-for-breast-cancer.html. Published October 27, 2021. Accessed October 7, 2022.
9 Bradley R, Braybrooke J, Gray R, et al. Aromatase inhibitors versus tamoxifen in premenopausal women with estrogen receptor-positive early-stage breast cancer treated with ovarian suppression: A patient-level meta-analysis of 7030 women from four randomised trials. The Lancet Oncology. 2022;23(3):382-392. doi:10.1016/s1470-2045(21)00758-0
10 Poggio F, Del Mastro L, Bruzzone M, et al. Safety of systemic hormone replacement therapy in breast cancer survivors: A systematic review and meta-analysis. Breast Cancer Research and Treatment. 2021;191(2):269-275. doi:10.1007/s10549-021-06436-9
11 Chien T-J, Hsu C-H, Liu C-Y, Fang C-J. Effect of acupuncture on hot flush and menopause symptoms in breast cancer- A systematic review and meta-analysis. PLoS ONE. 2017;12(8). doi:10.1371/journal.pone.0180918
12 Women – coping with sex hormone symptoms. Cancer Research UK.
https://www.cancerresearchuk.org/about-cancer/coping/physically/sex-hormone-symptoms/women-coping-with-hormone-symptoms. Published October 17, 2022. Accessed October 31, 2022.