Hormonal Therapy for Breast C... Video Transcript

Participants

Cathy Conley , Joanne E. Mortimer MD, Hope S. Rugo MD

Summary

Hormonal therapy is a well-established option in the treatment of breast cancer, but researchers are still learning how to use it more effectively in both early and late stages of the disease. Important new developments were a big topic at this year's 24th annual San Antonio Breast Cancer Symposium, and we sat down with two leading experts for an inside look.

Webcast Transcript

CATHY CONLEY: Hi, I'm Cathy Conley, and I'm here at the 24th annual San Antonio Breast Cancer Symposium, which has attracted leading medical experts from around the world.

One of the spotlights has been on hormonal therapy and how it is used to treat both early and advanced-stage breast cancer. I sat down with some of the leading physicians to discuss the benefits of hormonal therapy and the latest developments.

CATHY CONLEY: Dr. Mortimer, why is hormonal therapy given to women with breast cancer?

JOANNE E. MORTIMER, MD: Hormonal therapy is given for a number of different reasons in women with breast cancer. It's often used to treat the spread of breast cancer, so metastatic disease. It can be used in women who have a new diagnosis of breast cancer, where the cancer is extremely large and we use hormonal therapy to shrink the cancer before surgery.

Another role for hormonal therapy is in preventing recurrence of breast cancer. Another reason would be to prevent breast cancer. We know that certain hormonal agents will prevent breast cancer from occurring in women who are a very high risk for developing breast cancer.

CATHY CONLEY: What's the difference between hormonal therapy in early breast cancer in the adjuvant setting as opposed to the metastatic breast cancer?

JOANNE E. MORTIMER, MD: Okay, when we talk about metastatic breast cancer, we're talking about the spread of breast cancer to the liver, lungs, bones. Cancer that is basically incurable. So our goal of treatment is to shrink the tumor, to decrease the likelihood that it will spread and to make the patient more comfortable. And hopefully, in doing so, also prolong their survival.

When we talk about adjuvant treatment, what "adjuvant" means is treatment that is given to mop up microscopic disease. So the cancer has already been treated with lumpectomy and radiation or with mastectomy. Hormonal therapy in that setting mops up those microscopic disease and increases the cure rate of breast cancer.

CATHY CONLEY: Dr. Rugo, what are the main differences between tamoxifen and aromatase inhibitors?

HOPE RUGO, MD: Tamoxifen is a drug which has been around now for over 20 years, now 25 years. It's a drug which we thought was an antiestrogen, or worked against estrogen, in the past.

But we now understand that tamoxifen is a drug called a "SERM" -- a selective estrogen receptor modulator. That means that tamoxifen can block estrogen by blocking the receptor in the cancer cell that estrogen binds to. So blocking the effect of estrogen and helping a cancer cell to grow. Or it can act like estrogen, binding to the estrogen receptor and doing just what estrogen does.

The aromatase inhibitors work by a very different mechanism. For premenopausal women, all the estrogen comes from the ovary. But in postmenopausal women -- when the ovaries have shut down, estrogen is still produced at lower levels, but still significant for breast cancer cells. And that's made by testosterone, or another hormone like testosterone, being converted with the enzyme aromatase to estrogen.

So the aromatase inhibitor works right at that step to block the production of estrogen, so you don't need the receptor. You don't have that problem of the drug acting in one way or another. It just removes the growth factor, estrogen, from the cancer cell by stopping its production.

CATHY CONLEY: Among the aromatase inhibitors, exemestane -- known as Aromasin -- is known as an irreversible steroid inhibitor.