Selective estrogen receptor modulators (SERMs) may help prevent certain types of breast cancer. Healthcare providers also prescribe selective estrogen receptor modulators to treat some breast cancers and osteoporosis.
Selective estrogen receptor modulators (SERMs) are hormone therapies that manage how estrogen works in your body. SERMs such as tamoxifen (Nolvadex®, Soltamox®) and raloxifene (Evista®) are effective treatments for some types of breast cancer and osteoporosis.
SERMs are medical multitaskers. They block estrogen from connecting with breast cancer cells, keeping the cells from multiplying. At the same time, SERMs act like estrogen, boosting estrogen levels in your bones and preventing osteoporosis.
Healthcare providers use SERMs to treat hormone receptor (HR) positive or estrogen receptor (ER) positive breast cancer. ER-positive breast cancer occurs when estrogen connects with proteins inside cancer cells, causing the cells to grow. It may also happen when estrogen and another hormone, progesterone, connect with proteins inside cancer cells.
Providers typically prescribe tamoxifen and/or raloxifene to:
Osteoporosis affects approximately 8 million women and people AFAB in the U.S. SERMs may slow bone loss and reduce risk of fractures in women with osteoporosis.
Yes, they are. Healthcare providers typically prescribe SERMs to prevent and/or treat ER-positive breast cancer. ER-positive breast cancer represents 67% to 80% of breast cancer in women and people AFAB and 90% of breast cancer in men and people AMAB. (For context, the American Cancer Society estimates that in 2023, nearly 300,000 people in the U.S. will be diagnosed with breast cancer.)
Yes, they are. In particular, studies show tamoxifen reduces breast cancer risk by 40% in women and people AFAB who haven’t gone through menopause. Here are other examples:
Studies show raloxifene may reduce the risk of spinal fractures in women and people AFAB who develop osteoporosis after going through menopause.
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That depends on your situation. People taking tamoxifen to prevent or treat breast cancer may take a pill or liquid medication every day for five years and then switch to another treatment, such as an aromatase inhibitor. Some people may be offered tamoxifen for up to 10 years. People who take raloxifene to reduce breast cancer risk take a pill every day for an indefinite period.
If you’re at high risk for breast cancer, taking SERMs may reduce that risk. Tamoxifen may keep cancer from coming back. It may also help to slow down cancer that’s spreading. Likewise, the raloxifene prevents and treats osteoporosis and may reduce breast cancer risk.
Like most cancer treatments, SERMs have side effects, some of which may cause serious medical issues. Common tamoxifen side effects include:
Other less common tamoxifen side effects include:
Tamoxifen side effects in men and people AMAB may include:
Less common side effects include:
Raloxifene side effects include:
Women and people AFAB often develop symptoms similar to menopause, such as hot flashes, trouble sleeping and dry vaginas. Some suggested ways to ease menopause symptoms include:
Call your provider if common side effects like hot flashes or night sweats seem to be getting worse. Rarely, selective estrogen receptor modulators (SERMs) may cause serious side effects, including stroke and pulmonary embolism. Call 911 or seek immediate medical attention if you have symptoms including:
Yes, natural phytoestrogens are a plant-based form of the SERM clomiphene citrate. Healthcare providers may prescribe clomiphene citrate (Clomid®, Serophene®) to boost ovulation in women and people AFAB. Soy-based foods contain phytoestrogens. Currently, there’s no evidence that eating soy-based foods reduces breast cancer risk.
A note from Cleveland Clinic
Breast cancer is the most common form of cancer affecting women and people assigned female at birth (AFAB). Osteoporosis affects about 8 million people in the U.S. For decades, selective estrogen receptor modulators (SERMs) have been making a difference for people living with one or both of these serious medical conditions.
SERMs help prevent breast cancer in people at high risk for the disease, and ultimately help people to live longer. They may also help women and people AFAB who have osteoporosis by slowing bone loss and reducing the risk of fractures.
If you’re at risk for breast cancer or you have osteoporosis, ask a healthcare provider to explain SERM benefits and risk factors. They’ll be glad to help you understand how selective estrogen receptor modulators work and if this treatment is appropriate given your situation.
Last reviewed by a Cleveland Clinic medical professional on 02/03/2023.
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