We launched the Army of Women® and the Health of Women [HOW] Study™ because we wanted to advance research into the cause—and prevention—of breast cancer.

It is widely accepted that breast cancer is caused by a combination of genetic, hormonal and environmental risk factors.

Your genes, you are born with. Your estrogen (hormonal) risk factors are linked to the age at which you begin menstruating and go into menopause; whether you use birth control pills or hormone replacement therapy, and for how long; and if you had children, at what age, and how long you may have breastfed them.

Environmental factors don’t just mean chemicals in the environment. The “environment” also includes behavioral factors like exercise, diet and alcohol consumption, and physical factors like radiation. It can also include social, economic, and cultural factors that influence your diet or might determine what chemicals you are exposed to.

But teasing out these environmental factors as well as looking at how they might interact is far from easy. Studies have found that breast cancer risk increases in women who move from low-income countries to high-incomes countries, which points to environmental risk factors. All too often, though, people see these findings and immediately point the blame at the chemicals used in the U.S. while downplaying our American lifestyle, which is known for its abundance of fast food restaurants, super-sized servings, and culture of driving—which are linked to obesity and, in turn, increased breast cancer risk.

Even if a study finds a correlation between, say, blood levels of a certain chemical and breast cancer, it doesn’t mean that the substance caused the breast cancer. Our bodies are far more complicated than that. Also, research suggests that when you are exposed to a carcinogen matters, too. Scientists refer to time periods in a woman’s life, such as puberty, when these exposures might matter most as “windows of susceptibility,”and they are trying to learn more about them.

Exposure to the drug diethylstilbestrol (DES) is a good example of how timing might matter. DES is a synthetic form of estrogen that was used between the 1930s and the 1960s to reduce the risk of miscarriage. Today, we know that daughters born to women who were taking that drug have an increased risk of developing breast cancer and clear cell adenocarcinoma, a cancer of the vagina and cervix. This would suggest we all stay clear of DES—which is why people are often surprised to learn that in postmenopausal women, DES can be an effective breast cancer treatment.

Endocrine disruptors, chemicals that may increase breast cancer risk because they change the amount of estrogen in the body, are another example. It’s easy to find people who point to endocrine disruptors as the cause of breast cancer. But not all endocrine disruptors are inherently bad. Tamoxifen—which disrupts estrogen’s path to the breast—and the aromatase inhibitors—which block an enzyme called aromatase that turns androgens into estrogen—are effective breast cancer treatments precisely because they disrupt estrogen production.

In its report “Reducing Environmental Cancer Risk,”the President’s Cancer Panel emphasized not only the need for more research on environmental risk factors but also how complex this type of research can be.

As you know, Dr. Susan Love Research Foundation would never shy away from something complex. That’s why our Army of Women will soon be recruiting women in the San Francisco Bay Area for a study investigating how chemicals in the environment might affect breast cancer cells and our Health of Women [HOW] Study now contains a questionnaire to learn more about environmental exposures over time.

We would be naïve to think that either of these studies will give us “the” answer. But  they will give us information that we can use to learn more about environmental and hormonal factors that interact with our genes and may set the stage for breast cancer to occur.

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20 Responses to The Environment and Breast Cancer

  1. Margaret Hughes says:

    Dr. Love,
    I am interested to know what you think of the fact that as a DES daughter I have had a foundation one report which shows anomalies in certain genes (FGFR1, MYC, MYST3, and ZNF703). I wonder if any one of these were impacted by DES. Thanks for your wonderful blog.

  2. Joan Hoey says:

    Dr. Love…..My Grandmother died of Breast Cancer in 1955….nothing could be done for her. I was 15 at the time and saw the disease in her breasts. I had breast cancer in 1987 and have participated in some of your studies.
    But…..I have two daughters that I worry about….and your articles about environment that can have an affect with cancer. One daughter who lives in New Mexico….is constantly exposed to farming chemicals added to soil and to livestock. The other daughter who lives in Washington State….works with candles, waxes and scents in her work shop. I constantly worry about both of them with our family breast history . They are knowledgeable to their risk factors and do have a Dr. which follows them yearly. However, after reading of you new program regarding the environment would you please add their names to your mailing list for future mailings.
    Elisabeth Hoey…….Lazyjgranch@ yahoo.com Ellyn Johnson……Ellyn@morningdewcandles.com

  3. Will the HOW Study look at the effects of genetically modified food products, and our unavoidable and ever-increasing exposure to glyphosates and 2,4-D?

  4. Melissa Canaday says:

    Dear Dr. Love.
    I live in NYC below 14th St and had to live with the aftermath of 9/11 for months. Many of the women I know who have had or have breast cancer all live below or worked below 14th St.
    I have no history of Breast Cancer in my family, at all. I am wondering if the putrid chemicals that burned for months could be a contributing factor. I’d love it if you could do a study on women who lived and worked below 14th St in NYC at the time of 9/11 and the effects of the chemicals and breast cancer increases on women who have zero family history of breast cancer. Here is a golden opportunity to find out how toxic chemicals and our bodies are at war with each other.

  5. GERRI WELLS says:

    I also lived in NYC for 9/11 on 3 st. and worked down there. The chemicals in the air where bad for a long time.Breast Cancer 2011. and many woman I know became sick after that. Thanks

  6. Kathie Noga says:

    As far as environmental factors toxic chemicals can cause cancer. You can also get cancer if you live too close to large transmission towers. Cell phone use can also cause cancer. Having your alarm clock too close to the bed can cause cancer. Better to use battery clocks or move it away from your head. My uncle and aunt got cancer when they were exposed to uranium mine.

  7. Joanna Price says:

    I am 63,and I am a DES daughter. We have no family history of breast cancer. It would be very interesting to have a study of DES daughters and their rates of breast cancer. Thanks.

  8. Lori says:

    I wonder about when I was growing up…our neighborhood was sprayed for mosquitoes quite often and us kids would run in the streets full of smoke.

  9. Hannah says:

    Your study misses some important questions and there was no space to add the information. I had abnormal breast cells for over 10 years. Doctor’s did biopsies every couple of years. Three years ago I had 8 pounds of ovaian benign tumors remove. A year later all fibroid and abnormal breast cells are gone. No one can explain. Why benign? Why is this not important.

  10. Cathy Swanson says:

    My mother had breast cancer in her late 60’s, had a mastectomy and no other treatment. She lived to be 93. I have just about finished treatment (6 chemo treatments, 6 weeks of radiation and continuing Herceptin infusions until the end of October) for breast cancer which, thankfully was not found in lymph nodes and had no genetic link. I did have two instances of micro calcifications which were surgically removed. I am a bit older than my mother was, and had 20 years of clean mammograms. I took birth control pills in my 20’s and hormone therapy for about 10 years as I entered menopause. I am wondering if my cancer could have been related to increased stress after my husband had a stroke last year. I was diagnosed 6 months after his stroke. I would be interested in your thoughts. Thanks.

  11. Pat Armstrong says:

    I cooked food in plastic containers in a microwave for years!! I wonder if that chemical exposure led to my breast cancer as I had no other risk factors (weight normal, exercise, no family history, breast feed 2 babies).

  12. Mary Whipkey says:

    I too ran behind mosquito spraying jeeps in the early 60’s. I have no family of history and got breast cancer…very conscious of foods, exercise and general health. I would love to have more information on that mosquito spray.

  13. Mona V. says:

    “But not all endocrine disruptors are inherently bad.” Other than those synthetic disruptors deliberately used for treatment, which ones are thought to be anything but inherently bad? (?soy?)
    Breast cancer incidence has been escalating over the last 4 decades in epidemic fashion. When looking at epidemiology……there must be historical perspective. What factors have significantly changed in the environment, to make us more vulnerable to this disease? What chemicals have we been exposed to in increasing amounts? Did the use of plastics and other toxic substances change during this time of history? Did exposure to increasing amounts (and increasingly toxic types) of pesticides play a role? Did our “lifestyle” really change so dramatically over these last 4-5 decades, so as to explain the rapid escalation of incidence of breast cancer?
    I think it is also prudent to think about the decreasing incidence of breast cancer in countries that have deliberately removed many of the suspicious toxic pesticides and other chemicals from within their borders. (ie – Israel, European countries). (Countries where they did not expect to see a resultant decrease in breast cancer, in just 1-2 decades, but have indeed seen that.)

  14. Anne Seeman says:

    I live in the San Francisco Bay Area, was diagnosed with breast cancer at age 44, with no family history. As an artist, and at a young age, I worked with a variety of chemicals, such as mineral spirits and varsol. At the time of my treatment, 3 other artist friends were also undergoing breast cancer treadment. I am glad to hear about this study, and hope occupational environments will be investigated as part of it.

  15. Denise Dobrowolski says:

    I am totally convinced that my breast cancer was caused by environmental factors. I worked in a office in a complex for 25 years on land where chemicals were dumped by a nearby chemical company before there were any regulations. I “did everything right”, according to my gynecologist. No history, ate right, exercised, breast fed both of my children, didn’t drink other than occasionally and didn’t smoke. There was a lot of stress on my job, however, which peaked just before my diagnosis. There are just too many employees who worked there and are still there, who have gotten cancer and other auto immune diseases. Some have died, (too many). I retired as soon as I was diagnosed which is why I’m still alive. I would love for someone to analyze the site and prove that it is a danger to everyone that works there.

  16. Denise Dobrowolski says:

    And I live on the east coast. I think some studies need to be done in this area also. I would participate if they were being done in my area (southeastern Pennsylvania). We have a large amount of industry in this area.

  17. Judy Lujan says:

    I am a survivor of 14 years; my mother only survived 3 years- 1971-1974. Your “The Breast Cancer Book” was my bible when I was diagnosed in 1999. I appreciate and am very grateful for all the research you’re doing. I have always been very curious about the emotional and stress. I don’t know how effectively this could be researched, but I do think this can be a cause of breast cancer.

  18. Jonathan says:

    Dr. Love,

    I believe this a very objective take on the “environment” and breast cancer. I don’t like to name names, but I find certain breast cancer organizations put FAR too much emphasis on potential, but unproven, environmental (meaning chemicals, pollutants) links, while blatantly minimizing the solid (and what should be empowering) science supporting individual lifestyle modification. Of course, no woman should ever have a child or have a child at an inappropriately young age just to modify her cancer risk; but weight loss, exercise, and judicious use of exogenous hormones do make a difference. These should continue to be emphasized, especially since they seem to be key players in the high incidence of perimenopausal/postmenopausal breast cancer in Western society.

  19. L Nielsen says:

    @Anne Seeman: San Francisco is an epidemological center for breast cancer, according to the CDC. Thought that may be of interest. (http://apps.nccd.cdc.gov/uscs/cancersbystateandregion.aspx)
    It is critical that science and medicine consider environmental factors and take action to block potentially dangerous increases in the introduction of chemicals into the environment while testing for carcinogenicity is being determined.

  20. Great info. Lucky me I discovered your site by chance (stumbleupon).
    I’ve saved it for later!

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