Overview

Some breast cancers need the hormones estrogen or progesterone to grow. These cancer cells have "receptors" on their surface that let hormones in. One type is called estrogen-receptor-positive (ER+) breast cancer. Another type is called progesterone-receptor-positive (PR+) breast cancer.

Hormone treatment may be used to keep these cancers from getting the hormones they need. It's like starving the cancer cells so they don't grow.

Treatment works in one of two ways:

• It lowers the amount of hormones your body makes.
• It blocks or changes the cell receptors. This keeps the hormones from getting inside to feed the cancer cells.

Hormone treatment may be used:

• After treatment for early-stage breast cancer. This reduces the chance that the breast cancer will come back.
• To shrink the size of the cancer before surgery.
• To treat advanced breast cancer or breast cancer that has spread beyond the breast.
• To help prevent breast cancer in people who are at higher risk for breast cancer. It can help lower their risk.

Types of hormone treatment

Medicines used for hormone treatment include:

• Selective estrogen receptor modulators (SERMs). They block the cell receptors from letting in hormones. They include:
  • Tamoxifen (Nolvadex).
  • Toremifene (Fareston).
• Aromatase inhibitors. These block the enzyme aromatase, which converts other hormones in your body to estrogen. They are used mostly in people who are past menopause. They include:
  • Anastrozole (Arimidex).
  • Exemestane (Aromasin).
  • Letrozole (Femara).
• GnRH or LH-RH agonists. They stop your ovaries from making estrogen. They include:
  • Goserelin (Zoladex).
  • Leuprolide (Lupron).
• Selective estrogen receptor down-regulators (SERDs). These block and change the receptors so that they can't take in estrogen.
  • Fulvestrant (Faslodex).
  • Elacestrant (Orserdu).

Sometimes the ovaries are removed with surgery or treated with radiation. This is done to stop the ovaries from making estrogen.

Side effects of treatment

The side effects of hormone treatment depend on the drug that is used.

Selective estrogen receptor modulators (SERMS).

Common side effects include hot flashes, vaginal dryness, less interest in sex, mood swings, and feeling very tired. These drugs also raise your risk for blood clots and endometrial cancer. And they may increase your risk of stroke and fatty liver disease.

Aromatase inhibitors.

These can cause joint pain, hot flashes, vaginal dryness, and less interest in sex. Using these medicines for a long time may cause bone thinning.

GnRH and LH-RH agonists.

These drugs can cause hot flashes, mood swings, and vaginal dryness. They can cause less interest in sex, trouble sleeping, and headaches. Risks also include bone thinning.

Selective estrogen receptor down-regulators (SERDs).

Common side effects include joint and muscle pain, lack of energy, nausea, vomiting, hot flashes, and a cough. These drugs may also increase your cholesterol and triglycerides.

Side effects of surgery

Removing your ovaries makes you start menopause, if you haven't started it yet. Menopause often has symptoms like hot flashes, vaginal dryness, urinating often, and having less interest in sex. And it raises your risk for other diseases, like heart disease and osteoporosis.

When your ovaries are removed, you can no longer get pregnant through sex.

Managing side effects

If symptoms—like joint pain, mood swings, and hot flashes—are mild, you may get some relief if you do physical activity, lower your stress, and dress in layers. Your doctor may recommend medicine for severe symptoms. Ask your doctor about ways to protect your bones if they're thinning because of treatment.