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Breast Cancer and Endocrine Therapy

Other Hormone Therapies: Arimidex, Femara, and Aromasin

Aromatase inhibitors block the effect of an enzyme that helps the body break down testosterone into estrogen. They include Arimidex and Femara.

Aromatase inhibitors delay the progression of breast cancer longer than tamoxifen in women with advanced breast cancer whose tumors rely on estrogen to grow. Specifically, Femara and Arimidex are used as part of the initial or follow-up treatment of hormone-sensitive breast cancer -- even those that have spread to other parts of the body -- in women who have gone through menopause. They are pills that are taken once a day.

Side effects of aromatase inhibitors include:

  • Nausea, vomiting, diarrhea, and/or constipation
  • Hot flashes
  • Headache
  • Bone pain
  • Severe fatigue
  • Skin rash
  • Swelling and fluid retention
  • Flu-like symptoms
  • Increased bone loss

Another drug, Aromasin, is similar to the aromatase inhibitors but is an aromatase inactivator. Instead of blocking the aromatase enzyme, aromatase inactivators actually destroy it.

Aromasin is currently used to treat postmenopausal women with breast cancer that has spread outside of the breast that was not responsive to tamoxifen. It's a pill taken once a day after meals.

Side effects of Aromasin include:

  • Nausea
  • Fluid retention and/or weight gain
  • Headache
  • Hot flashes


Zoladex and Lupron for Breast Cancer

Zoladex and Lupron are drugs that stop the production of estrogen. They are used in premenopausal women for the treatment of estrogen sensitive breast cancer.

Side effects of Zoladex and Lupron include:

  • Fluid retention
  • Hot flashes
  • Irregular menstrual periods
  • Pain at the injection site



WebMD Medical Reference

Reviewed by Arnold Wax, MD on May 07, 2012

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