Selective estrogen receptor modulators (SERMs)

Overview

Selective estrogen receptor modulators (SERMs) play a crucial role in both the prevention and treatment of specific breast cancers and osteoporosis. These hormone therapies, including tamoxifen and raloxifene, function by modifying the effects of estrogen in the body.

SERMs are particularly important in managing estrogen receptor-positive (ER-positive) breast cancer, which accounts for 67% to 80% of breast cancer cases in women and 90% in men. Their effectiveness is well-established:

Tamoxifen reduces breast cancer risk by 40% in premenopausal women.

• Following surgery for breast cancer on one side, tamoxifen lowers the risk of cancer developing in the other breast by 50%.
• In women with a history of breast cancer before menopause, tamoxifen decreases the likelihood of recurrence by 30% to 50%.
• For early-stage ductal carcinoma in situ (DCIS), tamoxifen can reduce the risk of cancer spreading by up to 50%.

Raloxifene is also proven to effectively lower the risk of spinal fractures in postmenopausal women suffering from osteoporosis.

Reasons for undergoing the procedure

Selective Estrogen Receptor Modulators (SERMs) are medications with multiple uses. They block estrogen from attaching to breast cancer cells, stopping those cells from growing. During that time, SERMs act like estrogen in the bones, helping to keep bones strong and prevent osteoporosis.

• SERMs and breast cancer: Your healthcare providers prescribe SERMs to manage hormone receptor (HR) positive or estrogen receptor (ER) positive breast cancer. This type of breast cancer occurs when estrogen, and sometimes progesterone, binds to proteins within cancer cells, stimulating their growth. Commonly prescribed SERMs like tamoxifen and raloxifene serve several purposes:
  • SERMs help prevent ER-positive breast cancer in individuals at higher risk, such as those with a family history or genetic predispositions. Tamoxifen is usually given to those who haven’t reached menopause, while raloxifene is prescribed for postmenopausal individuals.
  • SERMs lower the risk of cancer recurrence after surgery and can prevent cancer from developing in the opposite breast.
  • They help prevent the return of ductal carcinoma in situ (DCIS).
  • SERMs are also used to treat metastatic breast cancer and can be prescribed for men with breast cancer.
• SERMs and osteoporosis: SERMs can help slow bone loss and reduce fracture risk in individuals with osteoporosis.

Risks

The most common risk or side effects includes:

• Common tamoxifen side effects:
  • Hot flashes
  • Night sweats
  • Irregular periods or spotting (uterine bleeding)
  • Reduced libido
  • Vaginal discharge
  • Vaginal dryness or itching
  • Menstrual cycle changes (for those who have not reached menopause)
• Less common tamoxifen side effects:
  • Deep vein thrombosis (blood clots in large veins)
  • Pulmonary embolism (blood clots in the lungs)
  • Bone loss (for individuals who have not yet gone through menopause)
  • Uterine or endometrial cancer
  • Stroke
  • Cataracts
• Tamoxifen side fffects in men:
  • Hot flashes
  • Sexual problems
  • Fatigue
  • Rarely: deep vein thrombosis
• Raloxifene side effects:
  • Hot flashes (more pronounced in the initial six months of treatment)
  • Leg cramps
  • Swelling in the hands, feet, ankles, or lower legs
  • Flu-like symptoms
  • Joint pain
  • Sleep disturbances

Procedure

The details of SERM therapy can differ depending on individual circumstances. For patients using tamoxifen to prevent or treat breast cancer, the standard treatment typically involves taking a daily pill or liquid medication for up to five years. After this initial period, a healthcare provider may recommend transitioning to another treatment, such as an aromatase inhibitor. In certain cases, tamoxifen may be prescribed for as long as ten years.

Conversely, individuals taking raloxifene to reduce breast cancer risk will generally take a daily pill for an indefinite period, as determined by their healthcare provider.

Outcome

For individuals at high risk for breast cancer, SERMs can significantly lower this risk. Tamoxifen is effective in preventing cancer from returning and may help slow the spread of existing cancer. Similarly, raloxifene plays a dual role by reducing breast cancer risk and managing osteoporosis.

During SERM therapy, women may experience symptoms similar to menopause, including hot flashes, sleep disturbances, and vaginal dryness. To manage these symptoms, consider the following strategies:

• Hot flashes may be alleviated by reducing caffeine intake and incorporating plant-based estrogens from sources such as soybeans, chickpeas, and lentils into your diet.
• Incorporate regular physical activity into your routine to help with sleeping problem.
• Use vaginal moisturizers to provide relief for vaginal dryness.

If common side effects like hot flashes or night sweats become more severe, consult your healthcare provider. Although rare, SERMs can cause serious adverse effects such as stroke or pulmonary embolism. Seek immediate medical help if you experience:

• Sudden weakness on one side of your body or face
• Difficulty speaking
• Severe or sudden headaches
• Sudden shortness of breath
• Sharp pain in the chest, arm, shoulder, or jaw