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Hormone Therapy

Isaacs, Breast Medical Oncology

About two out of every three breast cancers are hormone receptor-positive—meaning they contain receptors for the hormones estrogen (ER-positive) and/or progesterone (PR-positive) and are fueled by these natural chemicals.

We offer the latest options in hormone therapy to lower hormone levels or stop them from acting on breast cancer cells. Also called endocrine therapy, this approach is often used in conjunction with other treatments. We also are investigating new drugs in clinical trials to overcome resistance in certain cancers.

We recommend hormone therapy for several uses:

  • After surgery (adjuvant) to reduce the risk of cancer returning
  • Before surgery (neoadjuvant)
  • If the cancer comes back or spreads

Types of Endocrine (Hormone) Therapy

Several types of hormone therapy are available:

  • Drugs that block estrogen:
    • Tamoxifen
    • Toremifene
    • Fulvestrant
  • Drugs that lower estrogen:
    • Aromatase inhibitors (AIs): anastrozole (i.e., Arimidex), exemestane (i.e., Aromasin) and letrozole (i.e., Femara)


Previously, the only option available for women at high risk for breast cancer was increased screening to detect cancer early or prophylactic surgery. Our research shows that drugs like tamoxifen, raloxifene and aromatase inhibitors can reduce the risk by about 50 percent for such women. These drugs are in a family of medications that manipulate a person’s hormone levels.

Before reaching any decision, our experts will discuss the risks, benefits and drawbacks with you and your family so you can choose what’s right for you.

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MedStar Georgetown University Hospital
3800 Reservoir Rd., NW
Washington, D.C. 20007

MedStar Montgomery Medical Center
18101 Prince Philip Dr.
Olney, MD 20832

MedStar Washington Hospital Center
110 Irving St.
Washington, D.C. 20010

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