Epidemiology of cancer and aging.

The incidence of cancer increases with age. Given the increasing older population, one may expect that by the year 2030 about 70% of all malignancies will occur in individuals aged 65 and older. The following information is obtained from clinical epidemiology: the elderly are more vulnerable than are younger individuals to environmental carcinogens and may represent a natural monitoring system for new carcinogens in the environment; the biology of cancer may change with age, with some cancers becoming more aggressive (leukemias, lymphomas, ovarian) and others more indolent (breast, lung); most cancers present at a more advanced stage in the elderly, which suggests underutilization of screening and ignorance of symptoms; cancer affects preferentially healthy older individuals; and multiple cancers become more common with age. On the basis of these findings, preventative and therapeutic strategies for the elderly may be formulated.