APC of Breast Diseases: Breast Cancer - Epidemiology, risk factors, and GeneticsBMJ 1994; 309 doi: https://doi.org/10.1136/bmj.309.6960.1003 (Published 15 October 1994) Cite this as: BMJ 1994;309:1003
- K M McPherson,
- C M Steel,
- J M Dixon
With 570 000 new cases in the world each year, breast cancer remains the commonest malignancy in women and comprises 18% of all female cancers. The incidence among women aged 50 approaches two per 1000 women per year, and the disease is the single commonest cause of death among women aged 40-50, accounting for about a fifth of all deaths in this age group. In the United Kingdom, where the age standardised incidence and mortality is the highest in the world, there are more than 15 000 deaths each year, and the incidence is increasing slowly, particularly among elderly women, by about 1-2% a year.
Of every 1000 women aged 50, two will recently have had breast cancer diagnosed and about 15 will have had a diagnosis made before the age of 50, giving a prevalence of breast cancer of nearly 2%.
Risk Factors for Breast cancer
Age The incidence of breast cancer increases with age, doubling about every 10 years until the menopause, when the rate of increase slows dramatically. Compared with lung cancer, the incidence of breast cancer is higher at younger ages. In some countries there is a flattening of the age-incidence curve after the menopause.
Age adjusted incidence and mortality for breast cancer varies by at least a factor of seven between countries. The difference between Far Eastern and Western countries is diminishing but is still about fivefold. Studies of migrants from Japan to Hawaii show that the rates of breast cancer in migrants assume the rate in the host country within one or two generations, indicating that environmental factors are of greater importance than genetic factors.