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10 slides generated from the cancer page, with a quiz from the open benchmark and speaker notes that cite the sources. Arrow keys move between slides; Print gives one slide per page.
Bowel cancer is rising in people under 50, for reasons that are still not understood, and it is usually found late because neither patients nor doctors expect it. Treatment is the same as in older adults and works as well stage for stage; the changes are earlier screening, genetic testing for everyone diagnosed young, and attention to fertility, work and family.
Early-onset colorectal cancer is defined by age under 50 at diagnosis. Birth-cohort analyses (Siegel and colleagues, 2017) showed that people born around 1990 have double the colon cancer risk and four times the rectal cancer risk of those born around 1950 at the same age, a rise seen across high-income countries and attributed to diet, obesity, antibiotics, the microbiome and other early-life exposures without any one cause proven; a colibactin mutational signature from pks-positive Escherichia coli acquired in childhood is enriched in early-onset tumours (Nature 2025). About one in six patients diagnosed under 50 carries a germline cancer-predisposition variant, half of them Lynch syndrome, so multigene germline testing is recommended for everyone in this group.
Most early-onset tumours are left-sided or rectal, microsatellite-stable and diagnosed at stage III or IV after months of rectal bleeding, iron deficiency or change in bowel habit that was attributed to haemorrhoids or irritable bowel. Stage for stage, outcomes are similar to older adults, and treatment follows the same pathways: surgery and stage-based adjuvant chemotherapy, total neoadjuvant therapy or organ preservation for rectal tumours, and genotype-directed therapy for metastatic disease. Young patients receive more intensive chemotherapy without evidence that it helps them more.
| Setting | Approach | Guideline |
|---|---|---|
| Screening and early diagnosis | Average-risk screening from age 45 (colonoscopy, faecal immunochemical test, stool DNA or blood test); earlier and more frequent colonoscopy for family history or a known syndrome; investigate rectal bleeding and iron deficiency promptly at any age. | not mapped |
| Diagnosis and staging | Germline multigene testing for every patient; mismatch repair, RAS, BRAF and HER2 testing; fertility counselling before treatment. | not mapped |
| Localised disease | As for colorectal and rectal cancer by stage: surgery, adjuvant FOLFOX or CAPOX for stage III, total neoadjuvant therapy or organ preservation for rectal tumours; no escalation on the basis of age alone. | not mapped |
| Metastatic disease | Genotype-directed therapy as for all metastatic colorectal cancer: checkpoint blockade if mismatch-repair deficient, encorafenib-cetuximab for BRAF V600E, HER2 or KRAS G12C combinations, otherwise chemotherapy with bevacizumab or an anti-EGFR antibody by sidedness. | not mapped |
| Survivorship | Structured exercise (CHALLENGE), long-term neuropathy and bowel function care, fertility and sexual health follow-up, financial and employment support. | not mapped |