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Am I at risk

Am I at risk of getting breast cancer?

The risk of developing breast cancer increases with age; an average European woman aged 25 years has a 1 in 15,000 chance of developing breast cancer; for a 30-year-old women the chance is 1 in 2,000, for a 40-year old woman the risk is 1 in 200, for a 50-year-old woman the chance is 1 in 50, for a 60-year-old women the chance is 1 in 23, and up to the age of 85 years the chance is 1 in 10. The number of cases of breast cancer is five times higher in Western countries than in Far Eastern countries such as Japan and China. However, Japanese women who move to the USA increase their risk of developing breast cancer, which shows that the environment also plays an important role. Risk factors are things that increase your chance of developing breast cancer. The main groups are shown below.

Cancer history Hormonal Lifestyle Other
Family history
Previous breast
cancer
Age when periods started
Age at first pregnancy
Age at menopause
Use of ‘the pill
Use of HRT
Obesity after the menopause
Diet
Alcohol
Stress
Smoking

Environment
Breast biopsy*
(See further below)

Cancer History Risk Factors

Family History of Breast Cancer

It is thought that up to 5% of all breast cancers are inherited owing to the presence of abnormal genes. These genes are passed on from mother to daughter, so having a first-degree relative (such as a sister or mother) with breast cancer will increase your chance of developing the disease. This is particularly true if the relative develops breast cancer in both her breasts, or before she reaches the age of 45 years. A family history of breast or prostate cancer in a first-degree male relative is also associated with a significant increase in breast cancer risk. Breast cancer in a distant relative has little effect on your breast cancer risk. Your chance of developing breast cancer doubles if one first-degree relative developed the disease before the age of 45 years. If two first-degree relatives developed the disease before the age of 45 years, then your chance of developing breast cancer is four times greater than normal.

Scientists have identified several genes responsible for transmitting breast cancer. Three of the most important of these breast cancer genes are called BRCA-1, BRCA-2 and P53. This inherited form of breast cancer usually develops before the age of 50 years. If a woman has not developed breast cancer by the age of 50 years, despite having a first-degree relative with breast cancer, it is unlikely that she carries the abnormal gene(s). The BRCA-1 gene is also associated with ovarian cancer. So, the presence of other types of cancer, such cancer of the womb or ovary, in addition to breast cancer, also suggests the possibility that there is a cancer-causing gene in the family. Testing for breast cancer genes is now possible, but may require the presence of living relatives who have had breast cancer, and it may also take a long time to identify the gene.

A significant family history of prostate cancer (early age of onset before the age of 55, more than one relative) is also associated with an increased risk of breast cancer.

Cancer of the Other Breast

This increases the likelihood of breast cancer in the remaining breast.

Hormonal Risk Factors

Starting Periods Before the Age of 11 Years

Women who have a history of starting their periods (menses) before the age of 11 years have a higher chance of developing breast cancer. This is thought to be due to their longer exposure to the female sex hormone oestrogen, which is an established risk factor for breast cancer.

Later Pregnancy

The risk of developing breast cancer increases by 5% for each year of delay in having the first full-term pregnancy. Women who have their first child before the age of 30 years have a lower risk of developing breast cancer than those whose first pregnancy occurs after the age of 35 years. Recent research indicates that breast-feeding also reduces the risk of developing breast cancer.

There is no scientific evidence that pregnancies which end in a spontaneous or induced miscarriage increase the risk of developing breast cancer.

Later Menopause

The average age of a woman upon reaching the menopause in western Europe is 50 years. Women who reach the menopause after the age of 53 years have a higher chance of developing breast cancer. Delayed menopause prolongs a women's exposure to oestrogen - just as does starting periods before the age of 11 years.

The Oral Contraceptive Pill

The taking of the oral contraceptive pill that contains oestrogen within the previous 10 years slightly increases the chance of developing breast cancer. The greater the oestrogen-content in the pill, the higher the risk of developing breast cancer. Again, this is because oestrogen increases the risk of breast cancer. However, breast cancer that develops in contraceptive pill users seems to be less advanced than in non-users.

Hormone Replacement Therapy (HRT)

Taking HRT after the menopause seems to increase the risk of developing breast cancer, especially if it is continued for more than 10 years. HRT, however, reduces the risk of brittle-bone disease (osteoporosis), bone fractures and large bowel cancer. It also improves the symptoms of the menopause, such as vaginal dryness, hot flushes and depression. It is currently thought that HRT should be avoided where possible in women with a personal or a significant family history of breast cancer. A recent American study (Women's Health Initiative) has shown that taking HRT increases the risk of breast cancer and coronary heart disease. Therefore the author believes that the benefit-risk balance for HRT is negative and that the lowest dose should be used for the shortest time if required.

Lifestyle Risk Factors

Obesity

Obesity after the menopause increases the risk of breast cancer in women, whereas obesity before the menopause seems to reduce breast cancer risk. In post-menopausal women the body fat is the main source of oestrogen production; so obese women will have more oestrogen on board, thus increasing their breast cancer risk. (The main source of oestrogen production in pre-menopausal women is the ovaries.)

Diet

The research studies looking at the issue of diet and breast cancer show conflicting results. However, it is thought that a high intake of saturated animal fats and red meat (especially if overcooked) increases the risk of developing breast cancer, whereas diets high in fibre and vitamins (A, C and E), such as fresh fruits and vegetables, decrease the risk. It is also thought that fish and green tea reduce the risk of breasr cancer.

Alcohol Consumption

Recent evidence suggests that alcohol intake increases the likelihood of breast cancer. The risk seems to increase with all types of alcoholic drinks.

Smoking

There is increasing evidence that both active and passive smoking increase the risk of breast cancer especially in women younger than 50 years.

Other Risk Factors

There is no evidence that the personal use of deodorants or hair-dyes increases breast cancer risk.

The Environment

Earlier we said that Japanese women who had moved to the USA developed a similar breast cancer risk to that of the American population. This indicates that there are powerful environmental factors influencing the risk of developing breast cancer. Apart from diet and life-style, certain chemicals, such as pesticides, are thought to increase the risk. As yet, there is no established evidence to support this link. Exposure to radiation also increases the risk of many cancers, including breast cancer. It is important to realise that the radiation dose used in mammography (X-rays of the breast) is too small to be a significant risk factor.

Previous Benign Breast Biopsy

The risk of breast cancer is not significatly increased if you have had a previous breast biopsy (surgical) for a benign condition, such a cyst or a simple fibroadenoma. However, the presence of certain microscopic features in a breast biopsy is associated with a higher risk. For example, the risk is increased by 4-5 times if a condition known as atypical epithelial hyperplasia is found in the breast biopsy.

Mammographic Density

Mammographic density in 75% or more of the breast is associated with an almost fivefold increased risk of breast cancer, and this risk persists for an extended period of time. In addition, for women with extensively dense breasts, the masking effect of dense breast tissue increases the odds more than 17 times of a cancer being missed and then detected by non-screening methods. In such cases the addition of ultrasound scan and MRI imaging to digital mammography should be considered.