How Hormone Therapy Is Used to Treat Cancer

Some cancers depend on hormones to grow. Because of this, treatments that block or alter hormones can sometimes help slow or stop the growth of these cancers. Treating cancer with hormones is called hormone therapy, hormonal therapy, or endocrine therapy.

Hormone therapy is mostly used to treat certain kinds of breast cancer and prostate cancer that depend on sex hormones to grow. A few other cancers can be treated with hormone therapy, too.

Hormone therapy is considered a systemic treatment because the hormones it targets circulate throughout the body. The drugs used in hormone therapy travel throughout the body to target and affect hormones. This makes hormone therapy different from treatments that affect only a specific part of the body.

How Hormone Therapy Works

Hormone therapy travels throughout the body to find and target hormones. Different types of hormone therapy work in different ways. They can:

• Stop the body from making the hormone.
• Block the hormone from attaching to cancer cells.
• Alter the hormone so it does not work as it normally should.

Hormone therapy can be used to:

• Treat certain types of cancer by stopping or slowing their growth.
• Help lessen symptoms related to certain types of cancer.

Hormone therapy may be administered in different forms, including oral, subcutaneous, intravenous (IV), or intramuscular (IM) forms, depending on the specific medicine and treatment plan.

Types of Hormone Therapy

There are several different types of hormone therapy. The type of treatment used depends on the type of cancer, its hormone sensitivity, the patient's overall health, and other individual factors.

Breast Cancer

• Aromatase inhibitors (AIs): Such as anastrozole, exemestane, and letrozole.
• Selective estrogen receptor modulators (SERMs): Such as tamoxifen and raloxifene.
• Estrogen receptor antagonists: Such as fulvestrant and toremifene.
• Luteinizing hormone-releasing hormone (LHRH) agonists: Such as goserelin, leuprolide, and triptorelin.
• Surgery: Removal of the ovaries, known as an oophorectomy, may be used in certain situations to reduce estrogen production.

Prostate Cancer

• Anti-androgens: Such as apalutamide, enzalutamide, darolutamide, bicalutamide, flutamide, and nilutamide. These may be used as part of androgen deprivation therapy (ADT).
• CYP17 inhibitors: Such as abiraterone and ketoconazole.
• Luteinizing hormone-releasing hormone (LHRH) agonists and antagonists: Such as goserelin, leuprolide, triptorelin, and degarelix.
• Surgery: Removal of the testicles, known as an orchiectomy or surgical castration, can reduce testosterone production.

Endometrial Cancer

Endometrial cancer affects the lining of the uterus or womb. Hormone therapy options may include:

• Progestins: Such as medroxyprogesterone acetate or megestrol acetate.
• Luteinizing hormone-releasing hormone (LHRH) agonists: Such as goserelin and leuprolide.
• Aromatase inhibitors (AIs): Such as letrozole, anastrozole, and exemestane.

Adrenal Cancer

• Adrenolytics: Such as mitotane.

Hormone Therapy Side Effects

The side effects of hormone therapy can vary depending on the type of treatment, the medicine used, the dose, and the individual's health. Not everyone experiences the same side effects.

Possible Side Effects in Men

Men receiving hormone therapy for prostate cancer might experience:

• Hot flashes.
• Decreased sexual desire.
• Erectile dysfunction or trouble getting an erection.
• Bone loss and a higher risk of fractures.
• Fatigue.
• Weight gain, particularly around the abdomen, along with decreased muscle mass.
• Memory problems.
• Increased risk of certain other health problems.

Possible Side Effects in Women

Women receiving hormone therapy for breast or endometrial cancer might experience:

• Hot flashes.
• Vaginal discharge, dryness, or irritation.
• Decreased sexual desire.
• Fatigue.
• Nausea.
• Muscle and joint pain.
• Bone loss and a higher risk of fractures.
• Increased risk of certain other cancers, stroke, blood clots, cataracts, and heart disease, depending on the specific hormone therapy.

Conclusion

Hormone therapy can be an important treatment option for cancers that depend on hormones to grow. It works by reducing hormone production, blocking hormones from reaching cancer cells, or preventing hormones from functioning normally. The appropriate type of hormone therapy depends on the type and characteristics of the cancer and the patient's individual treatment needs.

Patients should discuss the potential benefits, risks, side effects, and available treatment options with their oncologist before starting hormone therapy.