News in Breast Cancer Research and Prevention

M. D. Anderson Cancer Center
Cancer Newsline Audio Podcast Series
Date: December 1, 2008
Duration: 0 / 10:29

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Leonard Zwelling, M.D:

Welcome to Cancer Newsline a weekly podcast series from The University of Texas M. D. Anderson Cancer Center in Houston TX. The aim of Cancer Newsline is to help you stay current with the news on cancer research, and the rapidly changing advances in cancer diagnosis, treatment and prevention, and provide you with the latest information on reducing your family’s risk of being diagnosed with cancer. I am your host Doctor Leonard Zwelling.

Today we will be talking about work being done to the relative contribution of environment verses genetics to the development of breast cancer and in addition I think we will try to cover a study that was recently published that used historical data to assess the risk of breast cancer recurrence in well treated patients with early breast cancer. Our guest today Abenaa Brewster assistant professor, Clinical Cancer Prevention and Kelly Hodges the program coordinator on the study we will discuss the sister study a long time nation wide study of women age 35 to 74 from different generations and from various racial and ethnical backgrounds who have or had a sister or sisters who had diagnosis of breast cancer and Kelly is from the Center of Research and Minority Health. Let’s start with the obvious first question why a study normal sisters of breast cancer patients. Kelly can you tell us something about that?

Kelly P. Hodges, M.S.:

What the study is looking at genes and environment because the sister that has been diagnosed with cancer. Once you receive the breast cancer diagnosis your body has changed a lot so they want to focus on the well sister because there has not been a major change in breast cancer as of yet.

Zwelling:

So do we know of any specific genetic links to breast cancer so far?

Abenaa Brewster, M.D.:

We do actually in a very small percentage of patients 10 percent of patients we know that women who have mutation and 2 specific breast cancer genes BRC1 and BRC2 have quite elevated lifetime risk of cancer and I think what were very interested in investigating is are the genetic factors that contributes to breast cancer among the majority of women who develop breast cancer.

Zwelling:

Of course the genetic risks are the ones that any patient couldn’t really do much about. What about the environmental risk? What have you found so far and what do we know?

Hodges:

Well as of right now with the study were in the preliminary phases and what we are doing here on the local level the center of research health we are just involved on the recruitment aspect of it. The research is actually being done at the National Institute of Environmental Health and so they are actually the researchers that are hands on and what we do here is… I’m recruiting African Americans, Hispanics, and older Americans into this study. So we have people here in Houston once a woman decides that she wants to be in the study we have a technician that comes out to take samples of nail clippings, dust from the home also take a urine sample and there are several questionaires that the well sister will take. Information is sent back to NIHS.

Zwelling:

Was this study initiated because people thought there is a higher incident of breast cancer in the sisters of people who have breast cancer that they think beyond the genetic link they thought it was much more to it then that?

Hodges:

Correct. The environment definately has an impact on that.

Zwelling:

What are the nail clippings for?

Hodges:

That’s a very good question Dr. Zwelling (laughing). Not really sure what the nail clippings are for all of that stuff is going to be tested. The nail clippings, the urine samples, the dust and it will be compiled over a ten year period of the women.

Zwelling:

So the study is trying to accomplish what specifically the relative contributions to breast cancer environment versus genetics?

Hodges:

Yes, that's the idea.

Zwelling:

Right now there’s information that suggest it could be both.

Hodges:

I don’t want to say either way We will let Dr. Brewster answer that question.

Brewster:

Absolutely, we know that both genes and environment play a really huge role causing cancer in general not just breast cancer and one of the things were interested in looking at is how those two factors interact with each other so we know the genes in of itself cause breast cancer in a majority of women but certainly some environmental exposure may cause those genes to cause breast cancer were really interested in looking at the interactions.

Zwelling:

What do we know about the environment exposures right now? Do have any idea of what they might be?

Brewster:

For cancer researchers environmental exposures are anything that’s not genetic. When we think about environmental exposures were thinking about reproductive risk factors. Whether woman has had children, how old she was when she started her menstrual period, whether she exercises, what is her weight, whether or not she drinks alcohol, smokes tobacco and so for us environmental factors are basically a woman’s lifestyle.

Zwelling:

Now what about issue of health disparities is there a greater risk of breast cancer in some ethic or racial groups and if so do we understand that at all?

Brewster:

Well we know that breast cancer in African American women those women tend to have breast cancer at a younger age and some of the risk factors to explain that genetics it may be different reproductive environmental risk factors. We also know that African American women once their diagnosed with breast cancer tend to have poorer survival and some of that may be contributed to the fact that diagnosed with late stages of the disease and that they may not have access to the care that other women have who are diagnosed with breast cancer. So health disparities plays a role not just the number of women that are diagnosed with breast cancer but also their survival.

Zwelling:

Lets talk about the study you just published in Journal National Cancer Institute which is about residual risk of breast cancer and which you were studying was what is the likely long term history of people of women who were well diagnosed and well treated. Did you have any surprises? What did your study show?

Brewster:

Well the reason why we conducted this study the very common question that’s asked by patients to their oncologist. Survive for five years at a point in time when there leaving our clinics and going back to there internist is” well what is the risk of my re-occurrence now Doc?" And that’s the question that we have a difficult time answering so this study looked at women who survived five years of breast cancer who as you said has been well treated and looked at the risk of late occurrence. What we found is that stage of diagnosis was still predictive of the risk of late occurrence. Women who were diagnosed with a early stage of breast cancer stage 1 had lower rate of occurrence.

Zwelling:

Stage 1 breast cancer would be?

Brewster:

Stage 1 breast cancer will be one that limited to the breast.

Zwelling:

Okay.

Brewster:

So these are women who do not have any lift notes involved or cancer in any other area but the breast and tumors is less then 2 centimeter and we found that those women had about a 7 percent risk of late recurrences. However women who were diagnosed with stage two and three breast cancers there larger tumors and tumors with lymph node involvement had a higher risk of late recurrences in the order of 10 to 13 percent.

Zwelling:

So the question of course is can you look at the women who recurred identify anything about them that will lead you to believe these are the women we need to treat more aggressively. What will that aggressive treatment… what might it be?

Brewster:

So, there are a couple of things that stood out that increased the risk of late occurrences. One was the fact that women who had tumors that were hormone receptor positive increase risk of late recurrences.

Zwelling:

So these are tumors that theoretically could grow in response to hormonal exposure.

Brewster:

Absolutly, These are tumors that are fueled by estrogen and we know that we can intervene these women because certainly for women who have hormonal receptor positive tumors who received Tamoxifen for five years. Umm…those women have a option of receiving aromatase inhibitors, drugs that block estrogen production. Well hopefully we showed in randomized studies also further reduce the risk of late reoccurrences and so there is a intervention that we can use for those women who have increase risk for late recurrences.

Zwelling:

So it’s a bit of individualism issue if you can identify these women upfront treat them properly these women may need to be exposed to certain types of drugs even longer then we originally thought.

Brewster:

Absolutely!

Zwelling:

That’s good so what about the sister study. What about the sister study. I just want to come back to that in just a minute. The goals of the sister study are defined environmental genetic factors may affect sisters. What about first degree relatives there mothers, aunts, second degree relatives?

Hodges:

Well we got that question before, we always get mother daughter teams that want to participate in the study and what we try to do is encourage them the participate in other ways by serving as advocates for the study and help us with the recruitment. This point in time the study is just for sisters that have been diagnosed with breast cancer.

Zwelling:

Very good, well thank you both for coming in today Dr. Abenaa Brewster and Kelly Hodges talking about risk and breast cancer. Listeners if you have any questions about anything you heard today please contact M. D. Anderson at 1-877-MDA-6789 or online www.mdanderson.org/ask. Thank you again both for coming in and again, this is a weekly podcast series. Tune in next week for our next episode in this series

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