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Side Effects of Hormone Treatment for Breast Cancer

Posted on September 07, 2022
Medically reviewed by
Todd Gersten, M.D.
Article written by
Emery Haley, Ph.D.

  • Hormone therapies for hormone receptor-positive breast cancer can lead to side effects such as hot flashes, vaginal dryness, pain, and nausea.
  • A variety of strategies can help you manage many side effects and improve your quality of life during hormonal treatment.

In hormone receptor (HR)-positive breast cancer, the cancer cells contain receptors to estrogen or progesterone — or both — and rely on signals from these hormones to help them grow. By reducing those signals, hormone treatments for HR-positive breast cancer work very effectively.

Although hormonal therapies — also called endocrine therapies — may be necessary for treating HR-positive breast cancer, they often have unwanted side effects. There are many strategies for managing these side effects and feeling your best while taking hormone treatments for HR-positive breast cancer.

Common Side Effects of Hormone Therapy

The ovaries produce estrogen and progesterone and control the menstrual cycle. Menopause occurs naturally when the ovaries produce fewer hormones, causing menstrual periods to stop. Because hormone therapies for HR-positive cancer reduce hormone signaling, they can also cause menopausal symptoms, especially for people who have not already experienced menopause.

Common menopausal symptoms include:

  • Hot flashes or night sweats
  • Vaginal dryness
  • Mood swings

Hormone therapies may also cause other side effects, which vary based on the type of medication.

Selective Estrogen Receptor Modulators

Medications called selective estrogen receptor modulators to include tamoxifen (Nolvadex, Soltamox), raloxifene (Evista), and toremifene (Fareston). Rare side effects include:

  • Cataracts (clouding of the lens in your eye)
  • Blood clots in the legs (deep vein thrombosis), lungs (pulmonary embolism), or brain (stroke)
  • Endometrial or uterine cancer

Because of the risk of cataracts, you should see an eye doctor before you start treatment, and follow up every six months. It’s also important to tell your cancer care team about any unusual pain, redness or swelling in the legs, shortness of breath, confusion, or difficulty moving, which can be symptoms of a blood clot. Unusual vaginal bleeding can be a symptom of endometrial or uterine cancer and should also be quickly reported to your doctor.

Selective Estrogen Receptor Degraders

Fulvestrant (Faslodex), a selective estrogen receptor degrader, may cause uncommon side effects including:

  • Headache
  • Dizziness or weakness
  • Pain in the bones, joints, or muscles
  • Flu-like symptoms
  • Digestive changes, such as constipation, diarrhea, nausea, or loss of appetite

Some rare side effects are more serious. Tell your doctor right away if you experience hives, breathing problems, fever, increased bleeding or bruising, swelling, or changes in mental health.

Aromatase Inhibitors

Aromatase inhibitors include letrozole (Femara), anastrozole (Arimidex), and exemestane (Aromasin). A common side effect of aromatase inhibitors is bone, joint, and muscle pain.

This pain can be so severe that people stop taking the medications. If you are finding side effects very difficult to manage, ask your doctor about alternative solutions, such as painkillers or a different type of hormonal therapy. Don’t stop taking any medication without first talking to your doctor.

Ovarian Suppression

Doctors may recommend various ovarian suppression treatments to stop the ovaries from producing hormones. The only permanent method is to surgically remove the ovaries (oophorectomy). Luteinizing hormone-releasing hormone (LHRH) agonist medications like goserelin (Zoladex) and leuprolide (sold under brand names including Lupron, Eligard, and Viadur) may also be prescribed to suppress ovarian function.

This type of treatment will cause menopause symptoms to develop suddenly. Although surgery leads to permanent menopause, LHRH drugs may cause menopause only temporarily, and these side effects may disappear once you are finished with treatment.

Managing Side Effects of Hormone Therapy

You can take charge to manage the side effects of your treatment. Options include medications, alternative therapies, supplements, and lifestyle changes, such as adjusting your diet.

Coping With Menopausal Symptoms

One common way of coping with symptoms of natural menopause is hormone replacement therapy (HRT), which involves taking hormones to make up for the decreased production that occurs with age.

HRT is not the same as hormonal therapy taken as a breast cancer treatment — hormonal therapy lowers hormone levels and HRT raises them. HRT is not an option for people with HR-positive breast cancer because it could cause cancer cells to grow. However, nonhormone prescription medications and alternative therapies can help relieve menopausal symptoms.

Hot Flashes and Night Sweats

Your doctor may prescribe medicines like venlafaxine (Effexor) or gabapentin (Neurontin) for hot flashes or night sweats. Alternative approaches like supplements and acupuncture are also popular ways to cope with these symptoms.

In a 2016 study, researchers found that a course of up to 20 acupuncture treatments over six months reduced the number of hot flashes and night sweats participants experienced. In another study, menopausal women experienced fewer hot flashes after five weekly hypnosis sessions. There is limited evidence for other approaches, such as taking supplements.

MyBCTeam members have found relief using these strategies. One wrote, “I was miserable when chemo threw me into immediate menopause. They finally tried gabapentin, and it was the only thing that worked for me.” Another member added, “My oncologist prescribed venlafaxine for hot flashes. It did help. I also had acupuncture.” A third member suggested, “Try evening primrose oil and sage tablets. It doesn’t take them away completely, but it does help.”

Some supplements, like black cohosh, could make breast cancer treatments less effective, so be sure to discuss alternative medicine approaches and supplements with your oncologist before trying them.

Vaginal Dryness

Treatments for menopause-related vaginal dryness usually involve moisturizing, which could mean simply using a personal lubricant during sex or masturbation. For vaginal dryness that causes discomfort all the time, a longer-acting vaginal moisturizer, like Replens, may be used.

Your OB-GYN may prescribe a topical estrogen cream, but check with your oncologist to see if this is a safe option for your cancer. Energy-based vaginal treatments, which use radiofrequency (Geneveve by Viveve and ThermiVa) or lasers (MonaLisa Touch, FemTouch, and FemiLift), may be another medical option. These treatments tend to be a bit more expensive, but they are hormone-free and have longer-lasting effects.

Members have also shared several suggestions and success stories for coping with vaginal dryness:

  • “My gynecologist prescribed topical estradiol cream for my vaginal dryness, and it worked well.”
  • “In my case, we’re trying to avoid hormone solutions, but my vaginal dryness is terrible. The best suggestion I’ve had so far is olive oil.”
  • “MonaLisa Touch was the game changer for me. It's a bit pricey, but I think it was so worth it.”

Mood Swings

Tips for dealing with mood swings include the following:

  • Avoid consuming caffeine, alcohol, and spicy foods.
  • Eat a balanced diet that includes healthy foods such as fruits, vegetables, and whole grains.
  • Get adequate sleep.
  • Engage in regular physical activity.
  • Find constructive ways to manage stress, such as practicing yoga, meditating, or talking with a therapist.

Weakened Bones

Over time, hormone therapies can cause bone loss, known as osteopenia or osteoporosis. You may need regular bone density tests to watch for weakened bones. Ask your doctor how often you should get this screening.

Coping With Nausea

Your doctor may suggest prescription medications such as ondansetron (Zofran) to prevent nausea and vomiting. As one member explained, “I had a lot of nausea, so I took the Zofran they gave me and never threw up.”

Other strategies for coping with nausea include:

  • Hydrating by drinking plenty of clear liquids
  • Eating smaller meals more frequently
  • Avoiding foods and drinks that can irritate your digestive tract, such as spicy foods, high-fat foods, dairy products, alcohol, and beverages that contain caffeine
  • Taking probiotics
  • Sipping herbal teas such as peppermint, ginger, or chamomile

Coping With Pain

Pain in the bones, joints, or muscles can be a side effect of many treatments, including surgeries, chemotherapy, and hormonal therapy.

Researchers have reported that routine exercise can significantly reduce pain. One MyBCTeam member who experienced pain and stiffness after taking anastrozole shared, “I walk for one and a half miles every evening, except when it’s raining. I’ve been doing it for nearly six months, and I am now pain-free.”

Pain can also be managed with:

  • Over-the-counter pain relievers including acetaminophen and nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and naproxen
  • RICE (rest, ice, compression, elevation) to reduce inflammation
  • Heat to relax muscles
  • Hands-on treatments (including massage, chiropractic care, and acupuncture)
  • Cognitive behavioral therapy to help you cope mentally and emotionally with pain
  • Biofeedback or stress management techniques to help you control how your body responds to pain

Talk With Your Health Care Team

Always speak with your oncology care team about your symptoms and concerns. Your oncologist can help pinpoint the source of your side effects and symptoms and provide options for managing them. If you’re finding the side effects intolerable, you can also talk with your doctor about other treatment options.

Never stop or change your breast cancer treatment without talking to your doctor first. Also, be sure to communicate with your care team before you try any new dietary supplements because some can have severe interactions with your medications or cause other side effects.

Talk With Others Who Understand

On MyBCTeam, the social network for people with breast cancer and their loved ones, more than 58,000 members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.

Have you found effective ways to manage the side effects of hormonal therapy to treat breast cancer? Share your experiences in the comments below, or start a conversation by posting on MyBCTeam.

  1. Hormonal Therapy —
  2. Menopause & Hormones Common Questions — U.S. Food and Drug Administration
  3. Bone Density Test — Mayo Clinic
  4. Hormone Therapy for Breast Cancer — American Cancer Society
  5. Watch for Ocular Effects of Breast Cancer Drugs — American Academy of Ophthalmology
  6. Blood Clots and Phlebitis —
  7. Endometrial Cancer —
  8. Fulvestrant — Memorial Sloan Kettering Cancer Center
  9. Aromatase Inhibitors for Lowering Breast Cancer Risk — American Cancer Society
  10. Hormone Therapy for Breast Cancer — Mayo Clinic
  11. Hormone Therapy: Is It Right for You? — Mayo Clinic
  12. Effexor Seems Just as Good as HRT in Easing Hot Flashes —
  13. Gabapentin for Hot Flashes in 420 Women With Breast Cancer: A Randomised Double-blind Placebo-Controlled Trial — Lancet
  14. Menopause — Mayo Clinic
  15. Acupuncture in Menopause (AIM) Study: A Pragmatic, Randomized Controlled Trial — Menopause
  16. Clinical Hypnosis in the Treatment of Post-Menopausal Hot Flashes: A Randomized Controlled Trial — Menopause
  17. Black Cohosh — Susan G. Komen
  18. Vaginal Dryness After Menopause: How To Treat It? — Mayo Clinic
  19. Energy-Based Treatments and Vaginal Rejuvenation — Cleveland Clinic
  20. Menopause — Endocrine Society
  21. Stress Management — Mayo Clinic
  22. Types of Anti Sickness Drugs — Cancer Research UK
  23. Bowel Changes — Cancer Council NSW
  24. Musculoskeletal Pain — Cleveland Clinic
  25. Breast Cancer Pain — Cleveland Clinic
  26. The Effect of Exercise on Aromatase Inhibitor-induced Musculoskeletal Symptoms in Breast Cancer Survivors: A Systematic Review and Meta-Analysis — Supportive Care in Cancer
  27. Pain Management — Cleveland Clinic
Posted on September 07, 2022
All updates must be accompanied by text or a picture.
Todd Gersten, M.D. is a hematologist-oncologist at the Florida Cancer Specialists & Research Institute in Wellington, Florida. Review provided by VeriMed Healthcare Network. Learn more about him here.
Emery Haley, Ph.D. is a nonbinary science communicator with a passion for diversity, equity, and inclusion in STEM. Learn more about them here.

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