Epidemiology and Mechanisms of the Increasing Incidence of Colon and Rectal Cancers in Young Adults

Gastroenterology. 2020 Jan;158(2):341-353. doi: 10.1053/j.gastro.2019.07.055. Epub 2019 Aug 5.


In contrast to the decreasing incidence of colorectal cancer (CRC) in older populations, the incidence has nearly doubled in younger adults since the early 1990s. Approximately 1 in 10 new diagnoses of CRC are now made in individuals 50 years or younger. Patients' risk of CRC has been calculated largely by age and family history, yet 3 of 4 patients with early-onset CRC have no family history of the disease. Rapidly increasing incidence rates in younger people could result from generational differences in diet, environmental exposures, and lifestyle factors. We review epidemiologic trends in CRC, data on genetic and nongenetic risk factors, and new approaches for determining CRC risk. These may identify individuals likely to benefit from early screening and specialized surveillance.

Keywords: Colorectal Cancer; Early-Age Onset; Epidemiology; Risk Factors.

Publication types

  • Research Support, N.I.H., Extramural
  • Review

MeSH terms

  • Age Factors
  • Age of Onset
  • Colonic Neoplasms / diagnosis
  • Colonic Neoplasms / epidemiology*
  • Colonic Neoplasms / prevention & control
  • Early Detection of Cancer / standards*
  • Humans
  • Incidence
  • Life Style*
  • Mass Screening / standards*
  • Patient Selection
  • Practice Guidelines as Topic
  • Rectal Neoplasms / diagnosis
  • Rectal Neoplasms / epidemiology*
  • Rectal Neoplasms / prevention & control
  • Risk Assessment
  • Risk Factors
  • Survival Analysis
  • Survival Rate
  • United States / epidemiology
  • Young Adult