Breast cancer risk factors

BREAST CANCER: RISK FACTORS

 

A cancer is a collection of cells which are growing and multiplying uncontrollably. Cancer of the breast is the most common type of cancer affecting women, followed by cancer of the uterus, lung and bowel.
Breast cancer is not a single entity; there are various cancers which can develop in the breast, many of which respond well to treatment and are not immediately life threatening. Early detection and diagnosis are important, as treatment of a small breast tumour at an early stage of development may have a better outcome than for most other types of cancer.
Some 75 per cent of breast cancers occur in women over the age of 40; only 2 per cent develop in those younger than 30. The vast majority form in the upper outer quadrant of the breast, and are relatively slow-growing tumours. The life expectancy of a woman receiving no treatment is about 3 years, although many women live with untreated tumours for 10 years or more.
Approximately 1 in 12 women in the UK will develop a breast cancer at some time during their lives. Although this figure may seem high, it is less surprising when compared with the figure of 1 in 3 or 4 people developing some form of cancer. However, this statistic needs to be put in context: the most common form of cancer in the UK is cancer of the skin, which in the majority of cases can be treated successfully.
Most of the risk factors associated with the development of breast cancer have been identified by large epidemiological studies, and the actual added risk these pose is usually very small. Many factors are not accepted by all experts as genuine risks. It has also to be borne in mind that women with all the risk factors may not develop breast cancer; and those with none may do so.
The two biggest risk factors are being a woman, and increasing age. Others may include a family history of breast cancer, having children at a late age, not breast-feeding children, or not having children at all. The most convincing evidence points towards a genetic predisposition in some women, especially those who develop breast cancer at an early age, some factors in the environment, possibly diet related, and the female hormone oestrogen. Different factors may play a part in different women, and some women are more prone to developing breast cancer than others.
Although mammography of young breasts is unreliable, breast screening should ideally begin at the age of 35 for women with substantial risk factors, rather than at 50 as is currently normal in the UK. Some large centers run special clinics for women in the higher risk categories. It is also very important that women in these categories learn the techniques of breast self-examination and of breast awareness.
Although there is controversy about the role of the various possible risk factors, the one thing that does seem clear is that the cause of breast cancer (and of many other cancers) is multi-factorial - various different factors combining together in an individual to result in its development. Environmental factors probably act through specific genes in those at risk.     *17/39/5*