In a nationwide retrospective cohort from The Netherlands (pop. ~17 million), a recent study (RM de Voer et al. Clin Gastroenterol Hepatol 2021; 19: 1642-1651. Full Text: Clinical, Pathology, Genetic, and Molecular Features of Colorectal Tumors in Adolescents and Adults 25 Years or Younger) characterizes the clinical and genetic features of colorectal cancer (CRC) in individuals <26 years of age (aka AYA group) from 2000-2017.

Key findings:

• There were 139 patients in the AYA group identified: 9 (ages 10-15), 26 (ages 16-20), and 104 (ages 21-25)
• Overall, the AYA group represents 0.1% of all CRC cases. However, AYA cases were much more likely to be at an advanced stage at diagnosis (66% at stage 3 or 4 compared with 46% of adults with CRC in The Netherlands).
• Negative predictors for outcomes included age <16 yrs, signet ring cell carcinoma histology, and advanced stage at diagnosis.
• Genetic tumor risk syndromes were identified in 39% and IBD was noted in 8.4% of the AYA group. The genetic risk is underestimated as the authors did not test for all CRC-predisposing genes. Lynch syndrome was the most common genetic disorder (identified in 22 patients) followed by familial adenomatous polyposis (identified in 5 patients)

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