It's natural to want to know your risk of getting breast cancer. But the answer isn't so simple. You can have lots of risk factors and never develop breast cancer. Or, you can have no risk factors and still develop it. Still, it may give you some peace of mind to know what these factors are and which ones you control.

Breast Cancer Prevention and Risk

One of the first questions people have about breast cancer is, "Can it be prevented?" The answer is, yes and no. Some factors you can control, others you can't. Of course, you should do all you can to control the factors you can. But after all is said and done, the value of early detection through breast self examination (BSE) and screening mammography still can't be emphasized enough. That way, even if you do get breast cancer, you have the best chance of beating it.

Breast Cancer Risks You Can Control

The good news is that you can do something about some factors that increase breast cancer risk. These factors relate to your lifestyle and exposure to certain kinds of drugs and treatments.

Hormones

Menstruation, menopause, and children

Scientists know for sure that hormones play a key role in determining breast cancer risk. The two important female hormones are estrogen and progesterone. They figure prominently in when start your periods, have babies, and experience menopause. The bottom line is that the longer you're exposed to these hormones, the greater your risk of developing breast cancer. Here's why:

Menstruation—The younger you are when you start your period, the higher your risk for breast cancer. This is because your body will have been exposed to female hormones longer. For each year after age 11 that you started your period, your risk of developing breast cancer decreases 20 percent.

Menopause—The older you are when you stop menstruating, the higher your risk. Once again, your body will have been exposed to female hormones longer. For example, women who start menopause before age 45 have one-half the risk of developing breast cancer compared to women who begin menopause after 55.

Childbirth—The risk of getting breast cancer is about 1.4 times higher for women who've never had children when compared to those who have. This is because women who've never been pregnant will have had a period every month, exposing them to female hormones longer.

Age at childbirth—The younger you are when you have your first child, the lower your risk for breast cancer. The risk for women who first give birth after age 30 is two to five times higher than for women who have their first child before age 18.

Breastfeeding—Studies suggest that nursing does have some affect on breast cancer risk. But a woman needs to have breastfed children for years to significantly reduce her risk.

All these hormonal factors may leave you wondering what your choices really are. After all, you can't change when you started your period. But you can:

• Choose whether or not to have a baby
  
• Decide how old to be when you have a baby
  
• Consider an oopherectomy (surgical removal of the ovaries) to bring on early menopause.
  This is only considered an option for women at very high breast cancer risk due to abnormal BRCA1 or BRCA2 genes.

Hormone replacement therapy

Hormone replacement therapy (HRT) also involves estrogen and progesterone, which are given to women after menopause to ease menopausal symptoms. It's now clear from medical research that HRT affects breast cancer risk in several ways:

• Breast cancer risk increases when HRT is used for more than five years, especially when both estrogen and progesterone were taken together.
  
• The risk of getting breast cancer reduces after you stop HRT.
  
• HRT increases your risk for breast cancer and does not reduce heart disease risk, which researchers once thought. In other words, the negatives probably outweigh the positives. Still, many doctors believe HRT is probably safe to take for shorter periods. Before you decide, make sure to discuss all the risk factors with your doctor.

Oral contraceptives

It's not real clear how oral contraceptives (birth control pills) impact breast cancer risk. Some studies suggest women who use "the pill" have a slightly higher risk than women who never used it. But the risk starts going down after use is stopped. In fact, women who stopped using the pill over ten years ago don't seem to have any increased risk at all. If you're thinking about using birth control pills, it's a good idea to first discuss all your breast cancer risk factors with your doctor.

Bodyweight

There are a lot of myths about the effects of weight on cancer risk. So be careful where you get your information. Here are the known facts:

Overweight women have a much higher risk of developing cancers of the breast, uterus, cervix, and ovaries.
Being overweight increases the risk of dying from cancer and accounts for 20 percent (1 in 5) of cancer deaths in women.

Obese woman have a significantly higher risk of death from cancer than normal weight women who contract cancer.

When you add it all up, losing weight could prevent one-out-of-six cancer deaths in the U.S. Doesn't it make sense to do all you can to become a lighter, healthier you?

Exercise

Studies prove that pre-menopausal women who exercise have a lower risk of breast cancer than women who don't. What's more, the particular type of exercise doesn't seem to matter—just as long as you do enough of it. Whether indoors or out, whether on your own, in a small class, or a large group, the important thing is to find something you enjoy and stick with it.

Alcohol consumption

No doubt about it, drinking alcohol increases your breast cancer risk. And it doesn't matter whether you drink beer, wine, or hard liquor. The risk also increases with the amount you drink. For instance, women who have one alcoholic drink a day have a small risk increase over nondrinkers. But those who have two to five drinks daily have about 1-1/2 times the risk of developing breast cancer compared to nondrinkers. The moral of the story is, if you don't drink, don't start. If you do drink, cut down. But the news gets better—research suggests taking folic acid daily could help offset breast cancer risk for women who drink alcohol.

Radiation exposure

Exposure to radiation increases breast cancer risk—if the radiation was directed at the chest area. Breast tissue is most susceptible to damage from radiation when it's still developing. So if you're exposed when you're over age 40, the risk increase is small. Don't worry about radiation levels during mammography—they're real low.

Other risks being studied

Lots of other risk factors for breast cancer have been proposed. Some of these claims can be taken seriously. But others are little more than Internet rumors. So don't believe everything you hear and be careful where you get your information.

High-fat diets—International studies have shown that breast cancer is less common in countries where the diet is low in total fat, polyunsaturated fat, and saturated fat. But studies of women in the U.S. have not found breast cancer risk to be related to fat intake at all. Researchers can't explain this disagreement yet, so more research is needed. But consider this: a high-fat diet has been shown to increase the risk of developing other types of cancer and heart disease. So cutting back on dietary fat certainly can't be bad.

Deodorants—Internet e-mail rumors have theorized that chemicals in underarm deodorants are absorbed through the skin and build up in the breast, eventually leading to breast cancer. There's zero evidence to support this rumor.

Bras—Internet e-mail rumors also have theorized that bras cause breast cancer by blocking lymph flow. The clinical evidence for this claim also is zilch.

Abortion—Several studies have produced very strong evidence to show that neither an induced abortion nor a spontaneous one (miscarriage) has any effect on breast cancer risk.

Breast implants—Several studies have determined that breast implants don't increase breast cancer risk, despite rumors to this effect that were circulated years ago.

Environmental pollution—Lots of research has been done to understand environmental influences on breast cancer risk. But it's pretty hard to make heads or tails of it. For example, women living on Cape Cod and Long Island have high rates of breast cancer. Many people believe toxic chemicals such as DDT are the real cause. But the charge is controversial and the research has been inconclusive so far. Chemical companies have lobbied hard to produce contradictory evidence. Meanwhile, further studies are in progress, backed by physician and patient advocate groups.

Smoking—A few studies have linked cigarette smoking to breast cancer. On the other hand, other studies have found no connection. The same goes for the connection between secondhand smoke and breast cancer risk. Still, we're 100% sure smoking is linked to heart disease, stroke, and lung cancer. So why go there?

Night work—Several studies suggest women who work at night—such as nurses on night shift—have an increased risk for breast cancer. It's a recent finding and more studies are being done. But some researchers think the reason is disruption in melatonin, a hormone affected by light.

Breast Cancer Risks You Can't Control

Sad to say, of all the breast cancer risks that exist, most are out of your control. The moral of the story is—never forget the #1 thing you can do to beat cancer—practice early breast cancer detection.

Gender

Breast cancer is such an overwhelmingly female disease that sometimes the fact is taken for granted. True, men sometimes get breast cancer. But the rate of breast cancer in women versus men is about 100 to 1 in the U.S. Simply put, just being a woman puts you at higher risk for breast cancer.

Age

The next most common breast cancer risk factor is age. Just consider a few statistics. 80 percent of breast cancers occur in women over 50. At 20, a woman's chances of developing breast cancer are less than 1 in 2,000. But at 70, they go up to 1 in 24. No, you can't do much about getting older, except to get wiser, too. But you can stay in good health and have regular mammograms and clinical breast exams, improving your overall health prospects.

Medical history

Certain factors in your previous medical history influence your breast cancer risk:

A history of breast cancer—If you've had breast cancer once, your risk of developing breast cancer in the other breast is three to four times higher than women who've never had breast cancer. But don't be overly alarmed. Only eight percent of women get a second breast cancer within ten years of the first occurrence.

Breast biopsy results with atypical cells—Sometimes a breast biopsy doesn't find cancer but detects pre-cancerous conditions, meaning cells in the breast that are abnormal (atypical). In this case, it's critical to make sure you have annual mammograms and clinical breast exams, since your risk of getting breast cancer is higher.

Family history

Having a family history of breast cancer also is a known risk factor. Women whose first-degree relatives (mothers, sisters, or daughters) had breast cancer are 1.5 to 3 times more likely also to develop breast cancer. The risk increases more if you have:

• More than one first-degree relative who's had breast cancer.
  
• A first-degree relative who developed breast cancer at an early age.
  
• A relative who had breast cancer in both breasts.
  
• A relative who had ovarian cancer.
  
• A male relative who had breast cancer.

If you have no first-degree relatives with cancer, having distant relatives with cancer has little or no impact on risk. So don't worry yourself by thinking of all your distant relatives who had cancer.

Ethnicity

Breast cancer rates do vary among ethnic groups, but the reasons why aren't so clear. For example, 1 in 40 Ashkenazi Jewish women has abnormal BRCA1 and BRCA2 (breast cancer) genes. Compare this with the general population, where the rate is just 1 in 650. This puts Ashkenazi women at higher risk for early-onset breast cancer, even when they don't have a family history of cancer. You can see why for Ashkenazi women early detection and genetic counseling are especially important.

In the U.S., breast cancer risk is highest among Caucasian women, followed in order by African American, Asian American, Hispanic, and Native American women. Across all ages, Caucasian women are more likely to develop breast cancer than African American women. But for some reason, African American women under age 40 have slightly higher rates of breast cancer than Caucasian's in the same group.

Genetics

BRCA1 and BRCA2

In recent years, scientists have identified two genes that provide new insight into breast cancer. Now that they know where the genes are, risk-reduction strategies may be possible. The two genes are BRCA1 and BRCA2 (BRCA just stands for breast cancer). All women and men have these genes. The cancer risk only increases when the gene is abnormal (mutated), which can be determined by a blood test.

BRCA1 or BRCA2 mutations put a woman at much higher risk of developing breast cancer. These women also are more likely to get breast cancer when younger, to develop cancer in the other breast, and to develop other forms of cancer. As frightening as this may sound, only about 1 in 650 people have an abnormal BRCA1 gene, and even fewer have an abnormal BRCA2 gene. Still, add all the statistics up and BRCA1 or BRCA2 mutations account for five to ten percent of all breast cancers.

The American Society of Clinical Oncology suggests you be tested for BRCA gene mutations if you have:

More than two first-degree relatives who had breast cancer, and one or more who had ovarian cancer.
More than three first-degree relatives with breast cancer diagnosed before they were 50.
Two sisters diagnosed with breast or ovarian cancer before the age of 50.
A first-degree relative who's had two breast cancers, two ovarian cancers, or breast and ovarian cancer.

If you think you might fit into this group, ask your physician to refer you to a genetic counselor. He or she can explain your risk of carrying an abnormal BRCA gene, along with all the pros and cons of genetic testing.

Other genes that may affect breast cancer

Scientists have discovered a few other genes that might be linked to breast cancer. These genes don't put women at as high a risk for breast cancer as BRCA genes, and they aren't inherited as often.

ATM—Normally, this gene helps repair damaged DNA in cells. But families with a high rate of breast cancer have been found to have mutations of this gene.

CHEK2—When this gene is mutated, breast cancer risk doubles. When it's mutated and there's also a strong family history of breast cancer, the risk increases much more.

p53—Normally this gene suppresses tumors. But when it's mutated, it can also increase the risk of developing breast cancer and some other cancers.

PTEN—This gene normally helps regulate cell growth. But inherited mutations in this gene increase the risk for tumors in the breast and other parts of the body.

Genetic counseling

If you're considering genetic testing, make sure to talk to a genetic counselor first. Your nurse or doctor can refer you to good one. You really need to understand and consider the benefits and risks of genetic testing before having them. Why? For starters, the tests are expensive and are not covered by all health insurance plans.

But there's another challenge you need to be aware of. Unless you're careful, the results might be used against you. Some people who've had abnormal genetic test results have been denied life insurance or health insurance. Or, if they did get it, they had to pay a whole lot more. Some states have passed laws to prevent insurance companies from denying insurance based on genetic testing results. But that doesn't mean the laws always work.