Like HowStuffWorks on Facebook!

Are Hormone Replacement Therapy and Breast Cancer Linked?: An Interview with Susan Love, M.D.


Susan Love, M.D., is an adjunct professor of Surgery at UCLA and the medical director of the Susan Love MD Breast Cancer Foundation, a nonprofit organization dedicated to the eradication of breast cancer. She is the author of "Dr. Susan Love's Breast Book" and "Dr. Susan Love's Hormone Book."

Can you talk about Hormone Replacement Therapy, or HRT, and breast cancer?

Well, we have had a problem in this country because we have medicalized menopause and we have said that somehow once you go through menopause your ovaries shut down and you are estrogen deficient and therefore you need to do something. And we put everybody on hormones really for the rest of their lives.

We are now finding out that this may not be such a good idea. For one thing, the hormones increase breast cancer, about one percent per year if you are just taking estrogen and about seven percent per year if you are taking estrogen and progestin. And secondly it is looking like they don't actually prevent heart disease the way we thought they did.

So the argument for taking hormone replacement therapy is really being questioned now and I think women need to realize that they may not be as safe as we thought.

Are you saying that HRT is a cause of breast cancer or do extra hormones help trigger it?

We actually don't know whether hormone replacement therapy causes breast cancer itself or whether it promotes it, whether it makes it grow faster or whether it is sort of the last trigger. But we certainly know that breast cancers in all — in test tubes and in animals—won't exist without hormones and that hormones, and estrogen particularly, are very important in the growth and development of breast cancer.

Is that only true of hormone positive breast cancers?

The theory is that all breast cancer starts our sensitive to hormones, so it is all hormone positive originally and then some of it becomes estrogen-receptor negative, so the breast tissue itself is all hormone positive. A typical hyperplasia, which is sort of one of the steps to breast cancer, is all hormone positive and then they become mostly hormone positive and invasive cancer is still mostly positive.

So you could argue that is one of the reasons for blocking hormones ... Even though the tumor eventually is estrogen-receptor negative, it still could have been caused by hormones.

Editor's Note: Since Dr. Susan Love gave this interview, the results of several large clinical trials on hormone- replacement therapy have been published. Articles on these trials, as well as other updates, can be found on the American Cancer Society Web Site.

Editor's Note: Since Dr. Susan Love gave this interview, the results of several large clinical trials on hormone- replacement therapy have been published. Articles on these trials, as well as other updates, can be found on the American Cancer Society Web Site.


More to Explore