Prevention of Breast Cancer

In the United States, breast cancer is one of the most commonly seen and diagnosed cancers among women, besides skin cancer. It accounts for 26 percent of all cancers among women. The lifetime risk of developing breast cancer for women is one in eight, or 12.41 percent, while unfortunately one in 38, or 2.62 percent, die from it. Global incidents are not equal. We see the highest rate of breast cancer in the USA and Northern Europe, and the lowest rate in Asia. There has been a gradual increase in Asia though, due to the adoption of a more western lifestyle and diet. The occurrence rate is highest just before 50 years old or menopause, while it is dramatically reduced after menopause.  

There are risk factors that can increase breast cancer occurrence. Some are genetic factors, which are not modifiable or hard for us to overcome. Others are modifiable or can be changed, such as stopping smoking. Risk factors that are difficult to modify or change are listed below.

Genetic history: If you have a personal or familial history of breast cancer, including DCIS (ductal carcinoma in situ) and LCIS (lobular carcinoma in situ), you will have increased odds for breast cancer or recurrence. If you've had one first-degree female relative (sister, mother, daughter) diagnosed with breast cancer, your risk is doubled. If two first-degree relatives have been diagnosed, your risk is five times higher than average. This genetic history is not something you can change. However, participating in a healthier lifestyle can mitigate or reduce some of these odds.

Genetic predisposition: BRCA1 and BRCA2 gene mutations in both men and women increase the risk of breast cancer. In women, the risks associated with a BRCA2 mutation appear to be about the same as those for BRCA1 mutations — a 50 to 85 percent risk of developing the disease by the age of 70. Again, participating in a cancer prevention lifestyle can help to reduce these odds.

Increased lifetime estrogen exposure: Having more exposure to estrogen is also a risk factor. Early-onset of menstruation (before age 11), late onset of menopause (after the age of 55), older age of first childbirth (such as after the age of 30 or never having given birth), and taking estrogen and progesterone supplementations (especially after menopause) can all increase the odds of breast cancer.

Dense breast tissue: Dense breast tissue can make one twice as likely to develop breast cancer as non-dense breasts. Having dense breast tissue can also make it harder for mammograms to detect breast cancer. There is no uniform method in determining dense breast tissue. Breast density is not based on how your breasts feel during your own self-exam or your OBGYN’s exam.  The only methodology currently accepted in measuring breast density is the thickness of tissue on a mammogram. If you have been diagnosed with having dense breast tissue, there are lifestyle modifications that you can make to reduce your breast cancer risk. These include maintaining a healthy weight, exercising regularly, limiting alcohol, eating nutritious food, and not smoking.

Prior radiation therapy to the chest region: If you have had radiation to the chest for treating other cancers, such as Hodgkin disease or non-Hodgkin lymphoma, you will have a higher risk of breast cancer. If you had radiation to the face as an adolescent to treat acne (which is no longer practiced), you are at a higher risk as well. The risk is higher when you are younger, especially when your breasts are still in the developmental stage. If you have used radioactive iodine to treat thyroid disease, you may be at an increased risk as well, but the evidence is not strong.  

Getting older: Two-thirds of invasive breast cancers are found in women 55 or older. While we cannot turn back the clock, we can live a healthier lifestyle that can decrease the odds of getting breast cancer. Having good, restful sleep is also conducive to our breast health.

Race and ethnicity: The lifetime risk (up to age 95 and older) of breast cancer for Caucasian women in the U.S. is about 13 percent, African-American women 12 percent, Asian/Pacific Islander 11 percent, Hispanic 10 percent, and American Indian/Alaska Native 8 percent. Caucasian women are more likely to be diagnosed with breast cancer, but African-American women are more likely to die from the disease. African-American women are also more likely to be diagnosed at a younger age (under 45).

Diethylstilbestrol (DES): Women who took the drug diethylstilbestrol (DES), which was given to some pregnant women in the United States between 1940 and 1971 to prevent miscarriage, have a higher risk. Women whose mothers took DES while pregnant with them are also at risk.


Below is a list of modifiable risk factors which you have the ability to make changes to.

Obesity: Being overweight or obese, especially after menopause, increases the risk of breast cancer. Having more fat tissue can increase your chances of getting breast cancer by raising estrogen levels. This not only raises the risk for getting breast cancer but also other types of cancers. According to the Centers for Disease Control and Prevention (CDC), more than 70 percent of American adults are overweight. This puts a lot of American women at risk for developing breast cancer. Of course, reducing weight can mitigate this risk, so exercise as a breast-healthy habit. As little as 75 to 150 minutes of brisk walking each week has been shown to lower risk. Ramping up your exercise routine even more may lower your breast cancer risk even further.

Alcohol consumption: Moderate alcohol consumption has been linked to an approximate 30 - 50 percent increased risk of breast cancer. The current definition of moderate alcohol consumption is around one to two drinks per day. Overall, the relative risk of breast cancer is increased by seven percent for each additional 10 grams of alcohol consumed per day. If you already have some risks for breast cancer, it might be wise to refrain completely from alcohol consumption.

Sedentary lifestyle: If you lead a sedentary lifestyle, you will have an increased risk of getting breast cancer. While there is no consensus on how much exercise is enough, we do know that some is better than none and vigorous activity is more effective than less vigorous activity. The American Cancer Society recommends all adults engage in at least 150 minutes of moderate-intensity or 75 minutes of vigorous-intensity activity each week, preferably spread throughout the week. I, personally, recommend that we do a regular 45-minute moderate daily exercise routine. This can include brisk walking, hiking, martial arts, tai chi, qi gong, dancing, leisurely bicycling, yoga, golfing, softball, doubles or singles tennis, jogging, running, fast bicycling, swimming, aerobic dance, soccer, basketball, and general yard and garden maintenance.

Taking hormones: Some forms of hormone replacement therapy (those that include both estrogen and progesterone) taken during menopause can raise the risk for breast cancer when taken for more than five years. Certain oral contraceptives (birth control pills) also have been found to raise breast cancer risk. It would be prudent to consult with your OBGYN before embarking on any kind of hormone replacement regimen.

Reproductive history and decisions: Having the first pregnancy after age 30, not breastfeeding, and never having a full-term pregnancy can all raise breast cancer risk. 

Prevention always starts with reducing risks. Some of the risk factors listed above you can change and some you cannot, but having a balanced and healthy lifestyle can always help to reduce risks further. Having restful and adequate sleep, moderate life and work stress, keeping your body fit and not overweight, eating a good diet, drinking plenty of clean water, and living a positive and constructive life can all help to reduce the risk of getting breast cancer.