The San Antonio Breast  Cancer Symposium is the most important breast cancer meeting that takes place each year.  It attracts close to 9,000 participants from more than 90 countries who are interested in hearing and discussing the most recent breast cancer research findings. The 33rd annual Symposium is being held December 8-12, 2010, and Dr. Love will be posting daily blogs about the meeting’s most interesting research reports and discussions.

Hormone Therapies
The first session of this year’s Symposium focused on hormonal drugs. Researchers reported findings from studies that showed that exemestane (brand name Aromasin) and anastrozole (brand name Arimidex) are about the same, with slightly less side effects for exemestane; that goserelin (brand name Zoladex) has the same benefit as tamoxifen when given to ER-positive premenopausal women for two years; that there was no benefit from taking goserelin and tamoxifen together; and that the benefit from goserelin, but not tamoxifen, was greater in tumors that were strongly estrogen receptor (ER) positive.

The next presentation, which reviewed two studies looking at the CYP2D6 test and the benefits of tamoxifen, were more interesting. The CYP2D6 test, also called the “tamoxifen resistance” test examines a gene called 2D6, which produces the enzyme CYP2D6. This enzyme is necessary for the body to metabolize a number of drugs, including tamoxifen. Tamoxifen has to be metabolized to endoxifen in order to work.  This is done in the body by enzymes. Some people have variations in these genes that result in them making less endoxifen, and there has been some data suggesting that these people don’t do as well when they take tamoxifen. This was noted at the 2007 San Antonio Breast Cancer Symposium, when researchers presented data that showed that women who inherited a certain variation of the 2D6 gene were almost twice as likely to have their breast cancer recur, even though they were more likely to complete their tamoxifen treatment.

To explore this question further, researchers took advantage of two large studies that were done to look at the benefit of tamoxifen versus an aromatase inhibitor (which is metabolized differently, and is not affected by CYP2D6).  Their findings refuted the previous data, showing that the presence of common mutations in the genes that control the enzymes that metabolize tamoxifen did not have an effect on whether women were likely to have a recurrence.   They also found that antidepressants that are thought to inhibit CYP2D6 actually had no effect on whether women taking tamoxifen had a recurrence. In sum, the researchers concluded that for postmenopausal patients with hormone-sensitive early breast cancer, CYP2D6 testing is not justified to determine whether to give tamoxifen. They also found that, in contrast to what has been suggested, the presence or absence of hot flashes should not be used as an indicator of whether tamoxifen is effective.

Basic Science
This meeting is a combination of basic science and clinical science. I always love the basic science sessions because I learn a lot.  One of today’s sessions focused on how cells metastasize, and what happens next.  The data shows that this is actually a very inefficient process, with  only 2% of the metastatic cells actually arriving at a new organ and with about one-third of these cells remaining completely dormant in the new organ for as long as 20 years or more.  Interestingly, in the researchers’ models, chemotherapy had no effect when the cells were dormant, but it did have an effect once the cells woke up.

Dormant means asleep, and the second speaker talked about how that dormancy works. This research team looked to see whether dormancy was related to blood supply (it wasn’t) or the balance between cell death and growth.  They found that the cells were basically just not dividing when they were dormant.  They then went on to see if there were molecular differences between the cells that woke up and those that did not, hoping that they could then go on to develop new drugs that target and stop the molecules that only are in the cells that wake up.  While that would be great, it made me think that we should also be looking at the environment that keeps the cells asleep.  After all, the goal is not to kill dormant cells but to live your life and die a natural death with the cells still dormant.

Obesity & Breast Cancer Survival
The talks that followed may have given us a clue to one factor in the cell’s environment that stimulates metastasis.  Researchers reported findings from three studies that analyzed the effect that being overweight or obese has on a woman’s risk of having a recurrence or dying of their disease.

The first set of studies looked at women with ER-positive, HER2-positive, or triple negative breast cancer.  These studies found a significantly higher risk of death from breast cancer in women who had a body mass index (BMI) over 25 (these are women considered overweight) who were ER positive. In fact, in premenopausal ER-positive women there was a 51% increased chance in death in the women who were obese!  This higher risk of death was not seen in women with a BMI over 25 who had HER2-positive or triple negative tumors.

A second study looked at women with locally advanced node positive (3 or more positive nodes) breast cancer.  This study also showed a worse prognosis in women who were obese. It was mentioned that the goal is not to become skinny, and it was reported that the Women’s Intervention Nutrition Study (WINS) showed that losing just 6 pounds made a difference in survival. The last study looked to see if it mattered whether women who were overweight were on an aromatase inhibitor or on tamoxifen. The researchers reported that it didn’t matter which therapy they were on, as the risk of death was the same for both treatments.

I couldn’t help but think that if we had a drug that had that much effect as obesity on women’s risk of dying of breast cancer we would be writing headlines! At this point I believe there is enough data to suggest that obese women should routinely be entered into a weight loss and exercise program as part of their treatment.

More tomorrow…

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14 Responses to San Antonio: Day 1

  1. Liz Anderson says:

    Thank you Dr Love for keeping us informed on the latest findings of breast cancer research. I truly appreciate and respect your opinion on recent findings.
    Looking forward to Day 2.

    DX 04/09 Stage 3a er/pr- her2+ 4+nodes

    Liz.

  2. Spring says:

    I almost felt like I was there! Great update! Keep ‘em coming!

  3. Debbi says:

    Thank you Dr. Love for making this information available to all of us.

  4. Kathie says:

    Thank you, Thank you, Thank you!!!!!

  5. Lesley says:

    If I’m on Tamoxifen and I’m premenopausal (48), would it be better to change to Goserelin (brand name Zoladex), for less dangerous side effects and better or the same results as Tamoxifen? I’m always worrying about the side effects of Tamoxifen.

  6. Chris says:

    Thank you for the updates. I look forward to the rest of the blogs.

  7. Pat says:

    Thank you for the summary. I try to read the notes from other sites and yours are so much easier to understand! I often wonder if the the drug companies are as interested in finding a “cure” for anyones illnesses or happier developing a pill that has to be taken daily for a lifetime.

  8. Pat says:

    Forgot to post 3 year Clear, Stage 1, 1.8 cm. er/p+

  9. Kathleen says:

    If you are premenopausal but past wanting to have children should we have a oopherectomy so we can get on an AI

  10. Denise says:

    I have Stage IIb breast cancer and I have battled obesity my entire adult life. With arthritis, and lumbar stenosis I am discouraged, but somehow not surprised, to find my obesity and limited mobility will negatively effect my survival. I do not intend to give up. I hope doctors don’t feel obese patients have a handicap that limits the medical options of obese patients. I am optimistic. Thank you for the information.

  11. KAREN says:

    THANKS FOR KEEPING US UPDATED. IT IS UPLIFTING TO HEAR THE DISCUSSIONS/RESEARCH FINDINGS BUT YOUR COMMON SENSE APPROACH IS WHAT WE ALL NEED! YOU ARE ASKING THE SAME QUESTIONS I HAVE! FIND THE LINK THAT KEEPS THE CELLS DORMANT, OR THE SWITCH THAT KEEPS THEM TURNED OFF, HOW DO WE KEEP OUR IMMUNE FUNCTIONS STRONG ENOUGH TO RID OUR BODIES OF TOXINS AND CANCER CELLS. I HAD STAGE 1 IN 2008 W/MASECTOMY, A SCARE IN 2009 W/MASECTOMY (WHICH WAS BENIGN) AND ALSO HAD RECONSTRUCTION. EVERYDAY I HEAR OF NEW CANCER CASES – THERE HAS TO BE A REASON. MY PRAYER IS THE CAUSE(S) WILL BE FOUND SOON AND THEN THE CURE WILL BE KNOWN. KEEP UP THE GOOD WORK!

  12. randi says:

    so I have the CYP2D6 gene, was taking off Tamoxifen, Dr. said the other meds would have the same reaction? DCIS stage 0, now reading that the reoccurance is higher?

  13. Ruth says:

    hi Dr. Love,
    Kindly verify the source of this study
    In-vitro and In-Vivo Comparison Study – potential utility of Curcumin on Her2+ Breast Cancer by a Taiwan hospital

    http://www.abstracts2view.com/sabcs10/viewp.php?nu=P2-21-01

    I thought this study was also presented during the San Antonio Breast Cancer Symposium last December 2010/

  14. Ruth says:

    here is another study- which I thought was also presented during the San Antonio symposium

    Clinical Studies presented by non-US based hospitals during the San Antonio Breast Cancer Symposium last December 2010
    Role of the Atr Protein Kinase and Curcumin in Tumor-Stromal Interactions in Breast Cancer (by a hospital in Riyadh)

    http://www.abstracts2view.com/sabcs10/view.php?nu=SABCS10L_512&terms=

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