Can you avoid breast cancer?

There are risk factors you cannot change and others you can control. About 30% of all breast cancers are thought to be due to lifestyle factors.

About one woman in eight will develop breast cancer at some point in her life. Three-quarters of them after menopause. In men, breast cancer is a very rare cancer. Men have about one chance in a thousand of developing the disease. Breast cancer in men represents less than one percent of all breast cancer cases worldwide.  

Age and gender are risk factors that you cannot change. You can do something about other risk factors, however.  

Risk factors you can't change  

Gender

Women are 100 times more at risk of breast cancer than men.  

Age

Most breast cancers occur in women over the age of 50. The older, the greater the risk. A woman aged 70 is at greater risk than a woman aged 50 or 60. Breast cancer is rare in women younger than 40.  

Family history and genetics

• Some people have a higher risk of developing breast cancer, compared to the risk of the general population, because other members of their family have had certain cancers. This is called a family history of cancer.
• If your mother, sister or daughter is diagnosed with breast cancer, your risk of breast cancer is approximately doubled. That risk is higher if more close relatives have (had) breast cancer or if a relative has developed breast cancer under age 50. However, most women who have a close relative with breast cancer will not develop the disease themselves.
• Some people have an increased risk of breast cancer because they have an inherited "gene defect. There are several "gene defects" that can increase the risk of breast cancer, and there are tests for some of them. Having one of these defective genes means that one is more likely to get breast cancer than someone who does not. But it is not a certainty.
• Most breast cancers occur by chance, but about 5 to 10% are hereditary, most of which are related to a change in the BRCA1 or BRCA2 gene. These are called breast cancer genes. In addition, there are other breast cancer genes, which are less common.

X-ray

Exposure to X- or X-ray radiation increases the risk of many types of cancer, but most people are never exposed to an amount of radiation to make much difference in our risk of cancer.

These days, doctors try to keep medical exposure to radiation as low as possible. They try to perform as few X-rays or CT scans as possible, unless they are really necessary, of course. As a matter of fact, the amount of radiation used is very small.

Many women worry about having a mammogram as part of breast screening because it exposes them to X-rays. However, the amount of radiation one receives from a mammogram is very small. The exposure is similar to the radiation exposure on a plane trip to New York.

Radiotherapy

Using radiotherapy to treat breast cancer in one breast only slightly increases the risk of breast cancer in the other breast. However, that small risk is offset by the need to treat the original breast cancer.

If one has had radiotherapy to treat another form of cancer, the risk of developing breast cancer is higher (compared to someone who has not had radiotherapy). This is especially true for women who have had breast therapy for Hodgkin lymphoma in the past. If you need radiotherapy for Hodgkin lymphoma or another cancer, it is best to discuss the risk with your doctor. One will offer breast screening if appropriate.

It is important to remember that breast cancer relapse is usually detected early when the initial breast cancer was successfully treated. Radiotherapy treatments are also more targeted now than in the past.

Other medical conditions

Women with diabetes have a slightly higher risk of breast cancer, than women without diabetes, although one is not sure why.

Dens breast tissue

The risk of breast cancer is higher in women with dense breast tissue (compared to less dense tissue). This is because they have less fat and more breast cells and connective tissue in their breasts. Our genetic makeup affects breast density.

Having a benign breast disease may increase the risk. There are 3 types of benign breast disease:

1. Nonproliferative
   Breast diseases that do not grow and in which the cells do not divide are called nonproliferative and usually do not increase the risk of breast cancer. However, if one has a strong family history of breast cancer, one may have a small increased risk.
2. Proliferative without atypia
3. Proliferative with atypia (atypical hyperplasia)
   Breast cysts with an overgrowth of cells (proliferation) but without abnormal (atypical) cells increase the risk of breast cancer compared with the average risk. About 1 in 20 breast nodules (5%) shows atypical hyperplasia. This means that the cells are not cancerous but grow abnormally. Atypical hyperplasia increases the risk of breast cancer by about 3 times the average. Atypical hyperplasia is unusual, and if one has not been told that the breast cyst showed these changes, one should not worry. One should always have the breasts checked first to make sure this is not cancer.

DCIS or LCIS

DCIS and LCIS are changes in breast tissue that could develop into breast cancer (called "precursors") in some women. DCIS stands for ductal carcinoma in situ. LCIS stands for lobular carcinoma in situ.

Women with a diagnosis of DCIS or LCIS have double the risk of having an invasive breast cancer in the same or another breast. But it is important to remember that most women with LCIS or DCIS will not develop an invasive cancer.

Age at which menstruation starts and stops

One has an increased risk of breast cancer if menstruation begins early (before age 12). If one has late menopause (after age 55) it increases the risk of breast cancer compared to women with earlier menopause. This may be related to hormone levels.

Hormones

Levels of the female sex hormone, estrogen, and the male hormone, testosterone, can affect the risk of breast cancer. Women have small amounts of the male hormone testosterone in their bodies.

After menopause, women with higher levels of estrogen and testosterone in their blood have a higher risk of breast cancer compared to women with the lowest levels. Women with higher levels of testosterone in their blood before menopause have a higher risk of breast cancer.

There is an increased risk of breast cancer in women with higher levels of a hormone called insulin-like growth factor 1 (IGF-1). It is not clear what regulates the levels of IGF-1 in the bloodstream. It is probably related to our genes, body weight and how much we exercise.

Ethnicity

A major study found that white women have a higher risk of breast cancer than any other ethnic group. This is at least partly due to lifestyle.

Have already had cancer

If one has had breast cancer, you have an increased risk of getting another breast cancer. The cancer may then occur in the same or the other breast. Your specialist will, of course, monitor this closely at your regular checkups. People who have previously had radiotherapy on the breast for Hodgkin lymphoma when they were young also have a higher risk of breast cancer.

Of course, having other cancers can also increase the risk of breast cancer.

The risk of breast cancer is also higher in people with any of the following conditions:

• Melanoma skin cancer
• Lung Cancer
• Bowel Cancer
• Uterine cancer
• A type of leukemia called chronic lymphatic leukemia

Not having children or having them later in life

Whether or when one can have children may not be something one can control. Women with children have a slightly lower risk of breast cancer than women who do not have children. The risk decreases further the more children one has.

Your age at which one has the first child also has an effect. The younger one is when one has the first child, the lower the risk.

Risk factors you can change though

Being overweight or obese

Women who are overweight after menopause have a higher risk of breast cancer than women who are not overweight. Men also have an increased risk of breast cancer if they are overweight or obese.

Overweight means having a Body Mass Index (BMI) of between 25 and 30. Obesity means being overweight with a BMI of 30 or higher.

It is important to maintain a healthy weight by being physically active and following a healthy, balanced diet.

Alcohol

Drinking alcohol increases the risk of breast cancer. Wine, beer or spirits make no difference. From one standard glass a day, the risk increases by 10 percent. What does that mean specifically? On average, a woman between the ages of 40 and 50 has a 1.45 percent chance of developing breast cancer. With one glass a day, her risk increases to 1.59% (+ 10%) and to 1.74% with 2 glasses a day (+ 20%). A woman between 50 and 60 has an average 2.4% chance of developing breast cancer if she does not drink; if she drinks one glass a day, her risk increases to 2.64% (+ 10%). With two glasses to 2.88% (+ 20%) and with 3 glasses to 3.12% (+ 30%).

According to the recommendation of the Supreme Health Council, it is best not to drink alcohol. If you do occasionally, keep it to no more than 10 units of alcohol per week.

Contraceptive pill

There is a very small increased risk of breast cancer when taking the birth control pill. This increase in risk goes back to normal 10 years after one stops taking it.

Breast cancer is rare in young women. Most women who take the pill are between the ages of 20 and 35. The small increase in this risk during the time women take the pill means very few additional cases of breast cancer.

Hormone therapy in menopause

Some women take hormone replacement therapy (HST) to reduce bothersome menopausal or menopausal symptoms. There are 2 main types of HST: combined HST (estrogen and progesterone) and HST with estrogens alone. Almost everyone uses the combined form. The form with estrogens is for women who had their uterus surgically removed for medical reasons. Combined HST (estrogen and progesterone) is more likely to cause breast cancer than HST with estrogen alone. The risk of breast cancer increases especially when women take HST for at least 5 years. The risk increase is limited and comparable to the additional risk with one to two alcohol drinks per day.

Take HST only in cases of bothersome symptoms and discontinue use once menopause is over. If you have had breast cancer, you should not take HST.

Not enough physical activity

There is an increased risk of breast cancer if you lead a sedentary life and have less than 150 minutes of moderate exercise per week.

Physical activity is more than working up a sweat at a gym. Activities that raise your heart rate, make you a little hot or make you a little out of breath count as moderate activity. Walking briskly for half an hour every day lowers your risk of breast cancer, and if you have breast cancer, exercise speeds your recovery and reduces the risk of relapse.  

Not breastfeeding

Breast milk is best for every newborn, there is no doubt about that. Yet it is not for everyone. Thanks to breastfeeding , you also have a lower risk of breast cancer. The protective effect is very modest: your risk decreases by 4% if you breastfeed for one year. If you breastfeed for 2 years, your risk decreases by 8%.

Smoking

Especially women who begin smoking at a young age are at greater risk of breast cancer. The risk is modest but increases with the duration and intensity of smoking.  

Risk factors for which there is no clear evidence

Some factors are suspected but not certain about increasing breast cancer risk. Some of these factors are:

The effect of nutrition

Much research has been done on whether nutrition increases the risk of breast cancer. To date, most findings are inconclusive and inconsistent. Previous research looked at the effect of a number of foods on breast cancer, including: dairy products, fiber, fruit, soy (soy), but found inconclusive.

Research on diet and breast cancer is very difficult because we all eat so many different types of food in such different amounts. A large study called EPIC (European Prospective Investigation into Cancer) is investigating the link between lifestyle and cancer. It includes about 520,000 people in 10 European countries.

Eating a healthy, balanced diet can help maintain a healthy body weight. Then again, there is evidence that being overweight or obese does increase the risk of breast cancer.

Night shift

Doing night work would increase the risk of breast cancer, but that effect seems to be more of an indirect consequence of the night shift. Women who do night work eat on average more unhealthily, which makes them more likely to be overweight, and they exercise less. Obesity and low exercise are risk factors for breast cancer.

Hormone disruptors

Endocrine disruptors are chemicals that can mimic and block the action of our own hormones because they happen to have a similar chemical structure.Most packaging contains endocrine disruptors. Avoiding them is an almost impossible task. Endocrine disruptors are associated with numerous diseases, including breast cancer. It is very difficult to estimate the real impact.