{"entity":{"id":"early-onset-colorectal","kind":"cancer","name":"Early-onset colorectal cancer (under 50)","aka":["Young-onset colorectal cancer","Colorectal cancer in adults under 50","Early-age-onset colorectal cancer","Bowel cancer in young adults"],"tldr":"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.","summary":"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.\n\nMost 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.\n\nThe policy response has been earlier screening: the American Cancer Society lowered the starting age for average-risk adults from 50 to 45 in 2018 and the US Preventive Services Task Force followed in 2021; European programmes are debating the same step, and polygenic risk scores may set individual starting ages. For patients, the distinct needs are fertility preservation before pelvic radiotherapy and oxaliplatin, sexual and stoma counselling, financial and employment support, and enrolment in the cohort studies trying to explain the rise.","asOf":"2026-09-17","wikipedia":"https://en.wikipedia.org/wiki/Colorectal_cancer","links":[{"label":"Wikipedia","url":"https://en.wikipedia.org/wiki/Colorectal_cancer"},{"label":"NCCN Guidelines: Colon Cancer","url":"https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1428"}],"tags":["subtype-page"],"related":[],"cancers":[],"sections":[],"technologies":["colorectal-screening","germline-testing","exercise-oncology","ai-endoscopy-detection"],"targets":["kras","braf","her2","pd1"],"drugs":["shield","cologuard","folfox","capox"],"companies":[],"institutions":[],"pathways":["colorectal-cancer-signalling"],"terms":["lynch-syndrome","msi","fit-test","colonoscopy","sidedness"],"trials":["challenge","nordicc","eclipse-shield"],"people":["chadwick-boseman","michael-bretthauer"],"bottlenecks":[],"keyPapers":[],"journals":[],"dependsOn":[],"notes":[],"group":"gastrointestinal","burden":"Roughly one in ten colorectal cancers in high-income countries is now diagnosed before 50, and incidence in this age group has risen by about 2 percent a year in the United States since the mid-1990s while falling in older adults; most are left-sided or rectal and diagnosed at a later stage.","subtypes":["Sporadic early-onset colorectal cancer (the large majority; mostly left colon and rectum, microsatellite-stable)","Hereditary early-onset colorectal cancer (Lynch syndrome, familial adenomatous polyposis and other germline variants, about one in six)","Early-onset rectal cancer (fertility, sexual function and stoma questions loom larger)","Mismatch-repair deficient early-onset tumours (immunotherapy as in other dMMR disease)"],"biomarkers":["Multigene germline panel for every patient diagnosed under 50","Mismatch repair / microsatellite status","RAS, BRAF V600E and HER2 as for all colorectal cancer","Colibactin (pks+ E. coli) mutational signature (research)","Iron deficiency and rectal bleeding as presenting signs at any age"],"standardOfCare":[{"setting":"Screening and early diagnosis","approach":"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.","refs":["colorectal-screening","fit-test","colonoscopy","shield","cologuard"],"guideline":{"version":"NCCN Guidelines: Colon Cancer","url":"https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1428"}},{"setting":"Diagnosis and staging","approach":"Germline multigene testing for every patient; mismatch repair, RAS, BRAF and HER2 testing; fertility counselling before treatment.","refs":["germline-testing","lynch-syndrome","msi","histopathology-ihc"],"guideline":{"version":"NCCN Guidelines: Colon Cancer","url":"https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1428"}},{"setting":"Localised disease","approach":"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.","refs":["folfox","capox","total-neoadjuvant-therapy","organ-preservation","rapido"],"guideline":{"version":"NCCN Guidelines: Colon Cancer","url":"https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1428"}},{"setting":"Metastatic disease","approach":"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.","refs":["pembrolizumab","encorafenib","tucatinib","sotorasib","bevacizumab","cetuximab"],"guideline":{"version":"NCCN Guidelines: Colon Cancer","url":"https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1428"}},{"setting":"Survivorship","approach":"Structured exercise (CHALLENGE), long-term neuropathy and bowel function care, fertility and sexual health follow-up, financial and employment support.","refs":["exercise-oncology","challenge"],"guideline":{"version":"NCCN Guidelines: Colon Cancer","url":"https://www.nccn.org/guidelines/guidelines-detail?category=1&id=1428"}}],"stateOfArt":["Screening now starts at 45 in the United States, the first policy response to the rise.","Universal germline testing in patients under 50 finds a hereditary syndrome in about one in six.","Mutational signatures are beginning to point at childhood exposures, including colibactin-producing bacteria."],"history":[{"year":2017,"title":"Siegel and colleagues show a birth-cohort rise in colon and rectal cancer in young adults","refs":["colorectal-screening"]},{"year":2017,"title":"Pearlman: about one in six patients under 50 carries a germline predisposition variant","refs":["germline-testing","lynch-syndrome"]},{"year":2018,"title":"American Cancer Society lowers the screening start age to 45","refs":["colorectal-screening"]},{"year":2021,"title":"US Preventive Services Task Force recommends screening from 45","refs":["colorectal-screening","fit-test"]},{"year":2025,"title":"Colibactin mutational signature found enriched in early-onset tumours (Nature)","refs":["colorectal-screening"]}],"pipeline":["idea-prev-prs-screening-start-age","idea-prev-reflex-germline-testing","shield","colorectal-screening","idea-prev-blood-crc-test-for-non-responders"],"openProblems":["The cause of the rise is unknown; no exposure has been proven.","Diagnostic delay in young adults with rectal bleeding remains long.","Whether screening should start at 45, 40 or by individual risk is unsettled outside the United States.","Fertility, sexual function and financial toxicity are poorly measured in trials."],"parent":"colorectal"},"route":"/cancers/early-onset-colorectal/","neighbours":{"technology":[{"id":"ai-endoscopy-detection","kind":"technology","name":"AI polyp detection in colonoscopy","route":"/technologies/ai-endoscopy-detection/"},{"id":"colorectal-screening","kind":"technology","name":"Colorectal cancer screening (colonoscopy, FIT, stool DNA, blood)","route":"/technologies/colorectal-screening/"},{"id":"exercise-oncology","kind":"technology","name":"Exercise & lifestyle oncology","route":"/technologies/exercise-oncology/"},{"id":"germline-testing","kind":"technology","name":"Germline (hereditary) testing","route":"/technologies/germline-testing/"},{"id":"histopathology-ihc","kind":"technology","name":"Histopathology & immunohistochemistry","route":"/technologies/histopathology-ihc/"}],"target":[{"id":"braf","kind":"target","name":"BRAF","route":"/targets/braf/"},{"id":"her2","kind":"target","name":"HER2","route":"/targets/her2/"},{"id":"kras","kind":"target","name":"KRAS","route":"/targets/kras/"},{"id":"pd1","kind":"target","name":"PD-1","route":"/targets/pd1/"}],"drug":[{"id":"bevacizumab","kind":"drug","name":"Bevacizumab","route":"/drugs/bevacizumab/"},{"id":"capox","kind":"drug","name":"CAPOX (capecitabine, oxaliplatin)","route":"/drugs/capox/"},{"id":"cetuximab","kind":"drug","name":"Cetuximab","route":"/drugs/cetuximab/"},{"id":"cologuard","kind":"drug","name":"Cologuard","route":"/drugs/cologuard/"},{"id":"encorafenib","kind":"drug","name":"Encorafenib","route":"/drugs/encorafenib/"},{"id":"folfox","kind":"drug","name":"FOLFOX (5-FU, leucovorin, oxaliplatin)","route":"/drugs/folfox/"},{"id":"pembrolizumab","kind":"drug","name":"Pembrolizumab","route":"/drugs/pembrolizumab/"},{"id":"shield","kind":"drug","name":"Shield","route":"/drugs/shield/"},{"id":"sotorasib","kind":"drug","name":"Sotorasib","route":"/drugs/sotorasib/"},{"id":"tucatinib","kind":"drug","name":"Tucatinib","route":"/drugs/tucatinib/"}],"pathway":[{"id":"colorectal-cancer-signalling","kind":"pathway","name":"Colorectal cancer (KEGG map)","route":"/pathways/colorectal-cancer-signalling/"}],"term":[{"id":"colonoscopy","kind":"term","name":"Colonoscopy","route":"/terms/colonoscopy/"},{"id":"fit-test","kind":"term","name":"Faecal immunochemical test (FIT)","route":"/terms/fit-test/"},{"id":"lynch-syndrome","kind":"term","name":"Lynch syndrome","route":"/terms/lynch-syndrome/"},{"id":"msi","kind":"term","name":"Microsatellite instability (MSI-H) / mismatch repair deficiency (dMMR)","route":"/terms/msi/"},{"id":"organ-preservation","kind":"term","name":"Organ preservation (watch-and-wait, bladder-sparing, larynx preservation)","route":"/terms/organ-preservation/"},{"id":"sidedness","kind":"term","name":"Sidedness (left vs right colon)","route":"/terms/sidedness/"},{"id":"total-neoadjuvant-therapy","kind":"term","name":"Total neoadjuvant therapy (TNT, rectal cancer)","route":"/terms/total-neoadjuvant-therapy/"}],"trial":[{"id":"challenge","kind":"trial","name":"CHALLENGE (CCTG CO.21)","route":"/trials/challenge/"},{"id":"eclipse-shield","kind":"trial","name":"ECLIPSE (Shield blood test)","route":"/trials/eclipse-shield/"},{"id":"nordicc","kind":"trial","name":"NordICC (Nordic-European Initiative on Colorectal Cancer)","route":"/trials/nordicc/"},{"id":"rapido","kind":"trial","name":"RAPIDO","route":"/trials/rapido/"}],"person":[{"id":"chadwick-boseman","kind":"person","name":"Chadwick Boseman","route":"/people/chadwick-boseman/"},{"id":"michael-bretthauer","kind":"person","name":"Michael Bretthauer","route":"/people/michael-bretthauer/"}],"idea":[{"id":"idea-prev-reflex-germline-testing","kind":"idea","name":"Automatic germline testing for every cancer type where it changes care","route":"/ideas/idea-prev-reflex-germline-testing/"},{"id":"idea-prev-blood-crc-test-for-non-responders","kind":"idea","name":"Offer the blood test for bowel cancer only to people who refuse stool tests or colonoscopy","route":"/ideas/idea-prev-blood-crc-test-for-non-responders/"},{"id":"idea-prev-prs-screening-start-age","kind":"idea","name":"Use a polygenic risk score to set when screening starts","route":"/ideas/idea-prev-prs-screening-start-age/"}],"cancer":[{"id":"aya-cancers","kind":"cancer","name":"Adolescent and young adult cancers (ages 15 to 39)","route":"/cancers/aya-cancers/"},{"id":"colorectal","kind":"cancer","name":"Colorectal cancer","route":"/cancers/colorectal/"}]}}