The Rise in Early-Onset Cancer in the US Population—More Apparent Than Real

Importance: Rising rates of early-onset cancer have generated substantial media coverage and public concern. In response, early-onset cancer has become a federal research priority, and clinical guidelines have shifted to recommend earlier screening for some cancers. Yet, it remains unclear whether rising rates represent a true increase in cancer occurrence or that these may instead be explained by increased diagnostic scrutiny. Observations: In aggregate, the 8 cancers with the fastest-rising incidence (>1% per year) in US adults younger than 50 years (thyroid, anus, kidney, small intestine, colorectum, endometrium, pancreas, and myeloma) have doubled in incidence since 1992, while the aggregate mortality for these cancers has remained flat. Colorectal and endometrial cancer showed a slight rise in mortality; for the others, stable or declining mortality alongside rising diagnoses suggests that greater detection (rather than more disease) accounts for the trend. In some cancers, such as thyroid and kidney cancer, overdiagnosis is well documented. For others, incidental detection or earlier diagnosis may explain the trends. While not among the fastest growing (0.6% per year), breast cancer remains the most common early-onset cancer, and despite rising diagnoses in women younger than 50 years, mortality has decreased by approximately half. Conclusions and Relevance: The rise in early-onset cancer incidence does not consistently signal a rise in the occurrence of clinically meaningful cancer. While some of the increase in early-onset cancer is likely clinically meaningful, it appears small and limited to a few cancer sites. Much of the increase appears to reflect increased diagnostic scrutiny and overdiagnosis. Interpreting rising incidence as an epidemic of disease may lead to unnecessary screening and treatment while also diverting attention from other more pressing health threats in young adults.