ANNOUNCER: Even when a woman with breast cancer is diagnosed early, she faces a significant risk of having the disease recur, after initial treatment by surgery.
GENEROSA GRANA, MD: To give you an example, a woman who has a 2 centimeter tumor and clean lymph nodes still has a 20% risk of developing metastatic spread of her cancer. That means that over the next 5 years, if no treatment is undertaken, she has approximately a 20% chance of developing spread of this cancer to the lungs, liver or bone.
ANNOUNCER: So while surgery is usually the first line of attack against breast cancer, most patients also undergo what's called "adjuvant therapy" to battle recurrence.
One approach is hormonal therapy, for a type of cancer that grows under stimulation of estrogen. Whether a woman has this type of cancer is usually determined by lab tests following initial treatment.
GENEROSA GRANA, MD: The presence of estrogen and progesterone receptors in cancer cells are determined at the time of surgery. When a woman has a biopsy, the tumor is tested for the presence of estrogen and progesterone receptors.
WILLIAM GRANDISHAR, MD: Estrogen and progesterone receptors are proteins that are present on the majority of breast cancers that develop in humans. Not all patients actually have tumors that have these estrogen and progesterone receptors. But when present, they indicate to us that manipulating the tumor using hormone therapy may be a possibility.
ANNOUNCER: For over 20 years, hormonal therapy has usually meant tamoxifen, the most widely used drug against breast cancer. Tamoxifen binds to estrogen receptors on cancer cells, preventing estrogen from doing so.
Tamoxifen is effective in women regardless of their age. But for women who are past menopause, there's another approach to hormonal therapy-using drugs that block the production of estrogen.