Multiple primary malignancies.

As the incidence and prevalence of cancer increase with age, it is reasonable to expect that the incidence and prevalence of multiple primary malignancies will increase as well. We ask here whether age is a risk factor for multiple primary malignancies and whether a special phenotype of older individual at increased risk of cancer may be identified. The main sources of information are autopsy series and tumor registries, which indicate that the prevalence and risk of multiple primary malignancies increase with age as expected, but that it is not possible to identify a particular phenotype that is at increased risk of multiple primary malignancies, among older individuals. It is also noted that the risk of endometrial cancer in association with breast cancer seems to increase in women aged 70 and older. Our conclusions are affected by the limitation of the sources themselves. These include for autopsy studies referral bias and overestimate of risk due to occult neoplasms, and for tumor registries, the quality and comprehensiveness of the registry and the evolution of diagnostic techniques overtime. Prospective follow-up of older cancer patients, involving measurement of circulating cytokines, whose concentration increases with age, and study of the genotype of older individuals, may provide new information about whether certain older individuals are at increased risk for multiple primary neoplasms.