Can we prevent breast cancer in our daughters?

The reason I’m so passionate about finding reliable, scientifically-based ways to prevent breast cancer, is the bright-eyed, ten-year-old girl that lives down the hallway.   If there is anything my daughter can do now to prevent the hell of breast cancer from visiting – and no, breast cancer is not pink, pretty, OR inspirational!- I want to know what it is.   Eat well?  Exercise? Throw out the Halloween candy?  What?

But looking at the evidence – none of those things seem to matter much.  When it comes to pre-menopausal breast cancer, the kind I had, and the kind that I worry about most for her, most of what we know about breast cancer just doesn’t apply.  In fact, one of the largest studies looking at prevention of breast cancer, the Nurses’ Health Study, found that many of the lifestyle associations with breast cancer -the ones you read about in the news – have OPPOSITE effects on pre- and post-menopausal breast cancer.

The Nurses’ Health Study is probably the largest and longest running study to look at factors associated with breast cancer development.   The study originally began in 1976, as a  study of the long-term effects of birth control pills.  Over 100,000 nurses have been followed since the beginning.  The nurses answer questions about health, smoking, hormone use, and menopausal status, every few years.  Questions about diet were added in 1980.  Over 115,000 additional nurses were added to the study in 1986.  It takes a long time, but this kind of study, a prospective study that follows people into the future, is the best kind of study to look at associations with development of disease.   It was a prospective study like this one, the Framingham Study, that gave us most of the information we have today about what contributes to heart disease.

The good news is that recruitment is underway for another group of nurses to join the study, younger and more diverse.  Plans are to invite a million women to join and to focus on adolescent diet and breast cancer risk, among other things.  The bad news is that it will be decades before we have the results.

So what can we say from the studies so far?  Women are at a slightly greater risk of premenopausal breast cancer while they are on birth contol pills, and for up to ten years after giving birth.  Even though giving birth, and giving birth at a younger age, is protective against post-menopausal breast cancer, is does appear to increase the  immediate risk of breast cancer for a period of time.

But one of the most surprising findings of the Nurses’ Health Study? Being overweight had the opposite effect on pre- and post-menopausal breast cancer.  For nurses in the study, being overweight increased the risk of post-menopausal breast cancer but decreased the risk of pre-menopausal breast cancer.  And more relevant to preteens, women who were overweight before their first periods had a lower risk of breast cancer.  That’s right, being overweight as a pre-teen was protective against breast cancer.

Physical activity?  According to the Nurses’ Study, activity was somewhat protective against breast cancer after menopause but had no impact on breast cancer before menopause.

Now, before I hear from Ann Fonfa, I want to be clear that I am not advocating for poor diets and increased weight for preteen girls, and either are the folks involved with the Nurses’ Study.   They were encouraged to find that if diagnosed with premenopausal breast cancer, those who were lean did tend to have smaller, and less aggressive cancers than those who were overweight.

From their newsletter, “Even though being active doesn’t offer much protection against pre-menopausal breast cancer – and being lean actually seems to increase risk – we still encourage women to be both lean and active throughout their lives.  The health effects of regular exercise and a low body mass far outweigh the risks of developing premenopausal breast cancer.  Furthermore, when premenopausal breast cancers do develop, they tend to be smaller and less-aggressive in leaner women than in overweight women.”

Any findings we can act on?  They have found a slightly higher risk of premenopausal breast cancer with higher intakes of animal fat, mostly high fat dairy, and mostly associated with estrogen receptor positive cancers.  And they found some suggestive results that higher consumption of Vitamin D and vegetables lowered the risk for premenopausal breast cancer, but not for postmenopausal.

Unfortunately, the biggest risk found for premenopausal breast cancer?  Having a mother diagnosed with breast cancer before age 45.  Damn.

So, bottom line for me and that ten-year-old?  I’m going to lighten up a little bit about the Halloween candy,  but continue using organic, non-fat milk and encourage the vegetables.  But in my heart I know, this  isn’t good enough.  We need to know more and do more to prevent this disease in these high risk, bright-eyed, ten-year-old girls that we love so much.  Please, don’t settle for the hyped news releases and the quasi- science.  Demand the right science so we can get the right answers!

Next, on to good basic science.  Could there be a shot (or three) to vaccinate our daughters against breast cancer? Check back ….

For more information on the Nurses’ Health Study, go to http://www.nurseshealthstudy.org.

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Comments

  • Joy Simha  On September 14, 2009 at 10:50 pm

    Laura,

    I agree wholeheartedly with you. Diet and exercise and limited alcohol make total sense for a person’s entire well being. But I share a few mantras regularly with both my kids: We are only promised today. Live this moment to the fullest; and You are in this life to have some fun, so get to it Kid!” I hope that they enjoy their lives. I do not want them to worry about how they will die. I truly believe we have no control over it.

    Thanks for blogging!

    Joy

  • Susan  On September 16, 2009 at 3:14 pm

    I lost my mother to breast cancer when she was 38, I was diagnosed at 44 and had a recurrence at 52. Despite the fact that I am the only one out of 4 sisters to have children I was the one to get breast cancer. I have a 25 year old daughter. She was very active athletically in high school and is on a low dose birth control pill at this time. She does not eat totally organic (I wish she did) since I really believe all the hormones and antibiotics in our food products are extremely bad for us especially with our predisposition to breast cancer. I hope and pray she continues her healthy lifestyle and remains cancer free. Since your daughter is in grade school and served probably cheap food I would make her lunch and limit the dairy they serve her since it is likely not hormone free.
    I agree to living each day to the fullest and my daughter and her dr. are well aware of her high risk for breast cancer.
    Thanks for the blog you keep.
    Susan

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