Epidemiology
Presentations and Publications
Incidence and prevalence
Breast cancer was recognised by the Ancient Egyptians as long ago as 1600 BC. However, over the past 50 years it has become a major health problem affecting as many as one in eight women during their lifetime.
The burden of breast cancer is increasing in both developed and developing countries, and in many of the regions of the world, it is now the most frequently occurring malignant disease in women.
Each year the disease is diagnosed in over one million women worldwide and is the cause of death in over 400,000 women.
Breast cancer can occur in men, although the incidence is much lower, amounting to around 1% of all breast cancers.
Overall the incidence of breast cancer rises with age, increasing rapidly during the fourth decade of life and continuing to increase thereafter, but more slowly in the fifth, sixth and seventh decades.
In the USA, 75% of new diagnoses of breast cancer are in women aged 50 years or older, and the lifetime risk of a diagnosis of breast cancer is approximately 12.5%.
The incidence rates for breast cancer are similar in North America and the majority of other western industrialized countries.
In Japan and other Far Eastern countries, however, absolute incidence rates are lower for each age band and overall Japanese women are five times less likely to develop breast cancer than American women.
However, Japanese immigrants to the USA have been shown to lose this advantage within 1–2 generations, which suggests that environmental factors play a role in developing the disease. Furthermore, the risk advantage demonstrated by native Japanese women may be dissipating; with the incidence of breast cancer in Japan doubling between 1960 and 1985. This change may reflect the increasing adoption of Western lifestyles in Japan over the last 50 years.
Ethnicity also plays a role in the risk of developing breast cancer. Although breast cancer remains the leading cancer in black women in the USA, overall they have an incidence rate nearly 20% lower than that of American white women.
Morbidity and mortality
The prognosis of breast cancer depends upon its stage at diagnosis (Figure 1). Data from the UK shows that 5-year survival rates range from 84% in women diagnosed with stage I disease to 18% in women diagnosed with stage IV disease (Figure 2).
Despite the increasing incidence rates of breast cancer, morbidity and mortality rates are beginning to fall. Data from the USA and UK show that between 1987 and 1997 there was a substantial reduction in breast cancer mortality, both in middle age (approximately 25%) and to a lesser extent in old age.
The suddenness of this decrease suggests that it is due to improvements in the way that the disease has been diagnosed and treated.
Figure 1. Staging classification of breast cancer
Link to more detailed information on Staging classification
For a link to disease progression slides click here
Figure 2. Breast cancer 5-year survival rates (UK, 1975-80) by stage at diagnosis
link to slides on survival data
Presentations for this page
Generations of Hope Through Breast Cancer Treatment - Professor M Baum (3882 kb)
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To download a presentation, simply right click on the link, and choose "Save Target As".
Publications for this article
- Breast cancer in older women
Author(s): I.S. Fentiman.
Journal: Breast Cancer Online. August 2002. 5(8).
- Ethnic Differences in Breast Cancer Characteristics.
Author(s): W.M. Butler & J. Cunningham.
Journal: Breast Cancer Online. May 2001. 4(5).
- New imaging techniques: role of digital mammography.
Author(s): M.R. Del Turco & B. Lazzari
Journal: Breast Cancer Online. May 2001. 4(5).
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