In hormone receptor (HR)-positive breast cancer, the cancer cells contain receptors for estrogen, progesterone, or both, and they depend on these hormones for growth. Hormone treatments for HR-positive breast cancer work by blocking or lowering the levels of these hormones, effectively slowing or stopping cancer growth.

Although hormonal therapies (also called endocrine therapies) may be necessary for treating HR-positive breast cancer, they often have unwanted side effects. Fortunately, various strategies can help you manage these side effects and maintain your well-being while undergoing treatment.

Common Side Effects of Hormone Therapy

The ovaries produce estrogen and progesterone, which regulate 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 trigger menopausal symptoms, especially for people who haven’t yet gone through 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 include raloxifene (Evista), tamoxifen, and toremifene (Fareston). Rare side effects include:

• Cataracts (clouding of the eye lens)
• 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, discoloration or swelling in your 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, and loss of appetite

Some rare side effects are more serious. Tell your doctor right away if you develop hives (itchy bumps on the skin), breathing problems, fever, increased bleeding or bruising, swelling, or changes in mental health.

Aromatase Inhibitors

Aromatase inhibitors include anastrozole (Arimidex), exemestane (Aromasin), and letrozole (Femara). These drugs commonly cause bone, joint, and muscle pain.

This pain can be so severe that people stop taking the medications. If you’re having trouble managing the side effects of these drugs, ask your doctor about alternative solutions, such as pain medications or a different type of hormonal therapy. Don’t stop taking any medication without first talking to your doctor.

Ovarian Suppression

Doctors may recommend ovarian suppression treatments to stop the ovaries from producing hormones. The only permanent method is oophorectomy (surgery to remove the ovaries). Luteinizing hormone-releasing hormone (LHRH) agonist medications such as goserelin implant (Zoladex) and leuprolide (sold under brand names such as Eligard and Lupron) may also be prescribed to inhibit 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 finish treatment.

Managing Side Effects of Hormone Therapy

You can take an active role in managing treatment side effects. Options include medications, alternative therapies, supplements, and lifestyle changes, such as modifying your diet.

Coping With Menopausal Symptoms

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

HRT isn’t the same as hormonal therapy taken as a breast cancer treatment — hormonal therapy lowers hormone levels, whereas HRT raises them. HRT isn’t an option for people with HR-positive breast cancer because the therapy could cause cancer cells to grow. However, nonhormonal prescription medications and alternative strategies can help relieve menopausal symptoms.

Hot Flashes and Night Sweats

Your doctor may prescribe a medication such as gabapentin (Neurontin) or venlafaxine (Effexor XR) to manage hot flashes or night sweats. Alternative approaches such as supplements and acupuncture are also popular ways to help ease these symptoms.

In a 2016 study, researchers found that receiving up to 20 acupuncture treatments over six months reduced the number of hot flashes and night sweats in participants. Another study, published in the journal Menopause, showed that postmenopausal women had fewer hot flashes after five weekly hypnosis sessions. There’s less evidence supporting other approaches, such as taking supplements.

MyBCTeam members have found relief using these strategies and shared comments such as these:

• “I was miserable when chemo threw me into immediate menopause. They finally tried gabapentin, and it was the only thing that worked for me.”
• “My oncologist prescribed venlafaxine for hot flashes. It did help. I also had acupuncture.”
• “Try evening primrose oil and sage tablets. It doesn’t take them away completely, but it does help.”

Some supplements, such as black cohosh, could make breast cancer treatments less effective. Be sure to check with your oncologist before trying alternative and complementary approaches, including supplements.

Vaginal Dryness

Treatments for menopause-related vaginal dryness usually involve moisturizing, which could mean simply applying a personal lubricant before sexual activity. For persistent vaginal dryness, a long-acting vaginal moisturizer, such as Replens, may be helpful.

Your OB-GYN may prescribe a topical estrogen cream, but it’s important to ask your oncologist if this is safe to use with 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 may cost more, 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.

Easing Nausea

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

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 or high-fat foods, dairy products, alcohol, and beverages with caffeine
• Taking probiotics
• Sipping herbal teas such as peppermint, ginger, or chamomile

Reducing Pain

Pain in the bones, joints, or muscles can be a side effect of various treatments, including surgery, 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

Regularly discuss your symptoms and concerns with your oncology care team. Your oncologist can help identify the source of your side effects and offer strategies to manage 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 73,000 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 your Activities page.