Gender
Although breast cancer is generally though of a women's disease, men get breast cancer too. Around 200 men a year are diagnosed with breast cancer compared with approximately 39,000 women.

Is breast cancer hereditary?
In most cases the answer to this question is no according to recent research. Only around 5% of all breast cancers are due to a hereditary factor. That said women who have a strong family history of breast cancer [I.E.: a close relative such as a Mother or Sister who developed breast cancer at an early age ] maybe at greater risk due to a genetic factor that can be passed down from one generation to the next.

BRCA genes and p53
The exact make-up of these two genes that may lead to a greater risk of breast cancer - BRCA1 and BRCA2 - has now been identified. If for some reason the make-up of these are changed, the risk of developing breast cancer increases, but it doesn't necessarily mean that the disease will definitely develop. Another gene, p53 is also now know to be involved in many cases of cancer, including breast cancer.

Vital research is still being conducted to identify other genes that, individually, may only make a small contribution to increasing the risk factor, when placed in certain combinations and environments increase the risk factors significantly. Known as breast cancer susceptibility genes these may also play a role in hereditary breast cancer.

The exact make-up of two genes which may lead to a tendency to breast cancer - BRCA1 and BRCA2 - is now known. If this make-up is changed (mutated), the risk of developing breast cancer may be increased, however it doesn't mean that the disease will definitely develop. Another gene, p53, is known to be involved in many cancers, including breast cancer.

Research is also being done to find other genes that, individually, may make only a small direct contribution to increasing risk, but have a much greater impact when combined in a 'package' of mutated genes or with environmental factors. These are known as breast cancer susceptibility genes and may also play a role in hereditary breast cancers.

Genetic Testing
In families where many women have had breast cancer, test can sometimes show the specific genetic changes that increase the risk of developing breast cancer.

Cancer family clinics (high risk clinics) are being set up throughout the country. They offer counseling, screening and, when appropriate, genetic testing. First, blood from a member of the family with breast cancer must be analyzed to find out the specific change in the gene. If a fault is found then testing can be offered to unaffected family members. This is a long process and can take many months.

Other Factors

While we know that age, gender and defects in certain genes have a direct effect on increasing the risk of breast cancer, the jury is still out on many other factors that may be important. Below we give an overview of the current thinking on key areas under investigation.

Hormonal History
The age that a woman starts her periods, and the age that she goes through menopause, can affect breast cancer risk. This is due to the influence of the female hormone oestrogen, produced during this time and known to stimulate many breast cancers. The longer a woman has periods, the greater her risk of developing breast cancer.

Does The Contraceptive Pill Cause Breast Cancer?
Some research has suggested that taking a pill with high levels of oestrogen for more than eight years may slightly increase breast cancer risk in young women. Other studies have reported different results so there's still some uncertainty.

Today most women take pills with low or no oestrogen. Doctors believe these are safe and may protect against cancer of the ovary and endometrium (lining of the womb).

Can Pregnancy Cause Breast Cancer?
No, doctors believe that pregnancy may have a protective effect on breast tissue. The younger a woman is when she first becomes pregnant, the lesser the risk. However, approximately 25 per cent of breast cancers occurring in younger women do so during pregnancy or one year afterwards.

Does Breast Feeding Have An Effect?
Some studies have shown a relationship between breast feeding and a lower risk of developing the disease, but at the moment there is no clear consensus on this subject. This effect has generally been seen if breast feeding continues for long periods, which may not always be possible in our society. There are many other positive effects of breast feeding for both mother and baby.

What about diet?
The incidence of breast cancer is higher in countries that eat a high-fat diet, though it's difficult to say whether diet is relevant in an individual woman. However, being obese appears to increase the risk of developing the disease in post-menopausal women because it increases the levels of circulating oestrogens. Healthy eating guidelines advise cutting down on fat to improve our general health.

Exercise
Some studies suggest that exercise can reduce the risk of developing breast cancer, and, as with diet, can help to reduce obesity and improve general health. Whilst the link with breast cancer is not clear, we should all take some form of regular exercise.

Alcohol
An increasing body of evidence suggests that drinking alcohol increases the risk of developing breast cancer, but further research is needed to establish how the two are linked. Government guidance suggests that women consume no more than 14 units of alcohol per week. The suggested limit is slightly higher for men at 21 units per week.

Does injury cause breast cancer?
No, but sometimes a woman may notice a lump after a knock because she feels her breasts more carefully.

What about stress?
At present there is no evidence that stress can increase the risk of a woman developing breast cancer. Research is continuing to investigate.

Further Reading:
Breakthrough.org.uk
National Breast Cancer.Org