Science, Politics and Mammography: An International Focus

I n developed nations around the world, breast cancer is the most common cancer among women (excluding nonmelanoma skin cancers) and is the second leading cause of cancer deaths in women (after lung cancer).1 While the incidence of breast cancer has been steadily increasing in all of the developed nations, breast cancer mortality rates have been declining significantly over the same time period. This decline in mortality is generally attributed to earlier detection and more effective treatments. Early detection increases the likelihood that the cancer will be identified at a more treatable stage rather than at a later stage when the likelihood of metastases, for example, is greater. Since mortality rates are directly related to the stage at which the cancer is detected, early diagnosis affords the individual a greater chance of long-term survival. When a cancer is confined to the breast, the five-year survival rate is close to 100%.2 Although the mechanisms of breast cancer development are not fully understood, many factors, such as age, ethnicity, heredity, diet and socioeconomic status are known risk factors for this disease. But, having one or more of these risk factors does not necessarily mean that breast cancer will develop. The majority of women with breast cancer have no known risk factors, and many women who do have them are cancer-free. Risk is based on probability and population averages. It does not imply inevitability.