Editorial comment

摘要

Renal cell carcinoma (RCC) has a steadily increasing incidence in the United States.1 The change in incidence and natural history of RCC is often attributed to the widespread use of abdominal imaging and the incidental detection of small renal masses. However, the etiology of sporadic RCC remains poorly understood. The authors present an analysis of Surveillance, Epidemiology, and End Results program data and should be commended for applying an age-period-cohort model to RCC. These data confirm the association between increasing age and the incidence of RCC. Period effects were identified that may represent the increasing use of abdominal imaging or other trends in medical practice. Notably, cohort effects, independent of patient age and treatment year, were also associated with the incidence of RCC. The authors point out that cohort effects may include "exposures, dietary factors, and habits specific to birth generations" that modify the risk of RCC. Cohort effects have also been demonstrated in kidney cancer mortality as well as in the incidence of testis cancer. ' Cohort effects, including the increased prevalence of obesity, diabetes, and metabolic syndrome, are likely to continue to drive the incidence of RCC in the United States.