What You Should Know About Breast Cancer Risk
“Drink more tea! Eat more vegetables! Throw out your antiperspirant!” Women are bombarded with advice on how to reduce their risk for breast cancer. What you often don’t hear is that none of these methods can guarantee you won’t get breast cancer, and much of this advice is based on inconclusive—and, sometimes, nonexistent—evidence. Before you start buying broccoli by the bushel, consider these facts about risk.
Risk reduction is not the same as prevention.
Until we know the causes of breast cancer, we cannot prevent it. Methods of risk reduction may lower your chances, but they don’t make you immune.
70% of people with breast cancer have none of the known risk factors beside age.
Not including being over age 50, the “known” risk factors for breast cancer (starting menstruation before age 12, starting menopause after age 55, having children after age 30 or not at all, having a parent, sibling or child with breast cancer) are present in only 30% of breast cancer cases.
(Source: US General Accounting Office, GAO/PEMD-92-12, 1991)
Risk factors do not cause cancer.
Finding out you are at “high risk” for breast cancer means you have a high number of risk factors for the disease. But risk factors do not cause breast cancer. Having one or more risk factors does not mean you will develop cancer.
Measuring individual risk is still a matter of guesswork.
Despite the fact that the “known” risk factors only explain 30% of cases, they are still used to determine whether you are at “high” risk. In addition, risk assessments are based on studies of large numbers of people. While these statistics are helpful at measuring trends, they are far less effective in calculating an individual’s risk.
“One in eight” is a lifetime risk.
This much quoted statistic is an individual’s cumulative risk over an 85-year lifetime. It does not mean that at any given point one out of every eight women has breast cancer. Rather, if all women lived to be 85, one in eight would develop the disease sometime during her life. The good news is that seven out of eight people will never get breast cancer. The bad news is that 30 years ago 19 out of 20 people never would.
Numbers aren’t always what they seem.
There’s a difference between relative and absolute risk. For example, imagine a study with 200 people. 100 people eat prunes, and another 100 don’t. One person in the prune-eating group gets cancer, while 4 in the non-prune-eating group get cancer. While the difference is three people, the relative risk reduction from eating prunes is 75% (three divided by the four). Pay attention to the real numbers behind the statistics.
It will take fundamental changes in society to truly prevent breast cancer.
There is growing evidence that our increasing use of pesticides and environmental toxins is making us sick. Despite this fact, the predominant message in risk reduction is “exercise and eat right.” It is far easier to tell people to eat less fat than it is to get corporations to stop using harmful chemicals. And while it may seem easier for us to change our lifestyles than to push for changes in society, it may be the only way we can stop the epidemic.
Join us as we press for the changes that will lead to true prevention and a real cure!
Myths and Facts about Breast Cancer Risk Factors:
Many so-called risk factors are characteristics beyond our control. You can’t change when you started your period or began menopause, or the fact that your mother has breast cancer (5–10% of breast cancer cases are inherited). Nor can you stop yourself from getting older (77% of breast cancer cases occur in women over age 50), or change your race (white women are at a slightly higher risk, but no racial group is without risk). So what can you do? There is a lot of talk about what you should and should not do to control your risk. Here are the facts:
“Risk Increasers”
Alcohol: Studies have been inconsistent, but some studies show that 2 or more drinks a day can slightly increase risk.
Antiperspirants: Antiperspirants and many other body care products can contain parabens (a preservative), phthalates (often an ingredient in “fragrance”), and other harmful chemicals, some of which may be linked to breast cancer. Learn more at the Think Before You Pink web site.
Birth control pills: Most studies show little or no increase in risk from taking birth control pills. A small increase in relative risk was seen during the use of birth control pills, and in the ten years after stopping use.
Bras: The idea that bras increase risk is based on the theory that bras slow the flow of fluids and keep toxins in the breast area. An interesting idea that hasn’t been studied much. There is little evidence to show that bras have an impact on risk.
High-fat diet: There are plenty of reasons to avoid a high-fat diet, but breast cancer is not one of them. Studies have not conclusively shown that a high-fat diet increases breast cancer risk. One largely ignored theory as to a connection between fatty diets and cancer is that some fatty foods contain high concentrations of pesticides.
Hormone replacement therapy (HRT): Breast cancer is an estrogen-driven disease, so it is not surprising that estrogen replacement therapy and HRT combining estrogen with progestin has been shown to increase the risk of breast cancer.
Obesity: Some studies suggest that obesity pre-menopausally reduces the risk for breast cancer, while post-menopausally it increases risk. This may be related to an increased amount of estrogen in the body that results from post-menopausal obesity.
Radiation: Ionizing radiation is a known cause of breast and other cancers. Sources of radiation include x-rays and nuclear waste. People should avoid unnecessary x-rays, especially in the teen years, when their tissue is growing and developing.
“Risk Reducers”
Breast-feeding: Breast-feeding your child appears to slightly decrease your risk for breast cancer. One well-researched explanation is that breast feeding reduces the amount of estrogen in your body. Another theory is that breast-feeding expels some of the accumulated toxins from the breast.
Diet/Nutrition: From tomatoes to tea, and flax seeds to soy, numerous items have been called “anti-cancer foods.” How much they can reduce one’s risk remains unknown. There appears to be some protection from monounsaturated fats like olive oil, and from green leafy vegetables and dark yellow/orange vegetables like carrots. This is a highly studied and highly controversial area of research.
Exercise: Results of studies have been mixed. While regular exercise is certainly good for your general health, its benefit for breast cancer risk reduction is not clear. Some studies show benefit from frequent strenuous exercise started in the teen years.
Prophylactic mastectomy: While a highly publicized study announced a 90% reduction in breast cancer deaths in women who had their healthy breasts removed, its important to note that in this study 7 women developed breast cancer despite the surgery, and over 600 women had needless surgery done.
Raloxifen: A drug currently prescribed for osteoporosis and being tested against tamoxifen for risk reduction (see below), raloxifen has not been approved for reducing the risk of breast cancer in healthy women.
Tamoxifen: Used to reduce the risk of recurrence in some women who have breast cancer and to treat breast cancer that has spread, this drug is being pushed as a so-called “prevention pill” for healthy women. The long term effects of the drug in healthy women is unknown. In one highly publicized study of this drug, 85 women taking the drug developed breast cancer, 3 of whom died, and an additional 2 women died as a result of side effects from the drug. Women considering tamoxifen for risk reduction should be extremely cautious. Contact BCA for more information. The decision to take this drug should not be taken lightly.
[Updated October 2004]