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Know Your Target: Treating Hormone-Driven Breast Cancer

Summary & Participants

Specific hormones cause nearly two-thirds of breast tumors to grow. Knowing which type of breast cancer you have can improve treatment.

Medically Reviewed On: July 08, 2008

Webcast Transcript

ANNOUNCER: When a woman is diagnosed with breast cancer, one of the first things physicians want to determine is the effect that estrogen has on the cancer. Although estrogen plays many vital roles in a woman's body, in nearly two-thirds of breast cancers, it can also stimulate cancer growth, making the determination of the cancer's estrogen receptor status crucial.

KIMBERLY BLACKWELL, MD: Estrogen receptor status really refers to whether or not a cancer cell has the estrogen receptor on it.

Estrogen is just a protein that's found in the female body. The way they interact is that estrogen would be circulating in the bloodstream, and when it encounters its own receptor, it will bind to it. In breast cancer cells that have the estrogen receptor, otherwise known as estrogen receptor-positive, that leads to the growth of the breast cancer cells. So in a sense, the estrogen binds to the estrogen receptor and acts, in a sense, like food for the breast cancer cell. It stimulates it to grow.

Estrogen receptor-negative tumors do not possess the estrogen receptor, which is simply a protein on their surface, and thus, we believe, do not depend on the female hormone estrogen for their growth.

ANNOUNCER: Another key hormone whose receptor status is important is progesterone, although its effect on cancer growth is not as well-defined.

MARY CIANFROCCA, MD: We do look for both estrogen and progesterone receptors in a patient's cancer. It's a little bit debatable right now whether that helps us in decision-making. There is some early evidence that patients do better if they're both estrogen and progesterone receptor-positive than if they're just estrogen receptor-positive and progesterone receptor-negative. So we do routinely test for both receptors in all patients' cancers.

ANNOUNCER: Estrogen and progesterone receptor status is usually determined at the time of diagnosis by performing a biopsy of a woman's breast cancer. These tests are highly accurate and give physicians an indication that certain forms of treatment may be beneficial for the patient.

MARY CIANFROCCA, MD: Once estrogen receptor status is known, decisions are made as to whether a patient can benefit from hormonal therapy. If a patient's estrogen receptor-positive, they have the potential to benefit from hormonal therapy, where if they're hormone receptor-negative, they don't have the potential to benefit from that type of therapy.

ANNOUNCER: Hormonal therapy removes the effect of estrogen, so breast cancer cells are not stimulated to grow. If a woman's breast cancer is in the early stages and is estrogen receptor-positive, there are a number of strategies that doctors use to reduce the amount of estrogen in a woman's body.

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