“My dad died young of bowel cancer and the hospital said it ran in the family — do I need testing? I’m only 22”

A strong family history of EARLY-onset bowel cancer across relatives, described as hereditary, suggests an inherited colorectal-cancer syndrome — notably FAMILIAL ADENOMATOUS POLYPOSIS (FAP) or Lynch syndrome (HNPCC) — and warrants a priority clinical-genetics referral (BSG/ACPGBI/UKCGG 2020); MUTYH-associated polyposis (autosomal recessive) and attenuated FAP are other possibilities. FAP (APC gene) is AUTOSOMAL DOMINANT, causing hundreds-to-thousands of colonic ADENOMATOUS POLYPS from adolescence with a near-100% lifetime colorectal-cancer risk if untreated, and extra-colonic features (duodenal/desmoid tumours, CHRPE, osteomas, thyroid); each child of an affected parent has a 50% chance of inheriting the faulty gene. Discuss PRESYMPTOMATIC GENETIC testing (often the family’s causative mutation is known and can be tested for) via clinical genetics, counselling that testing is the patient’s choice (right to know/not know, psychological and practical implications; ABI Code 2018 on insurance; cascade testing of relatives with consent, GMC Confidentiality 2017) and that early identification enables life-saving surveillance. For confirmed carriers, management is intensive surveillance and prevention — colonoscopy from age 12 to 14, usually prophylactic COLECTOMY when polyp burden warrants (late teens or early adulthood), and upper-GI (duodenal) surveillance — which dramatically reduces colorectal-cancer death. Distinguish LYNCH syndrome (far fewer polyps, earlier-onset colorectal cancer, and associated endometrial and other cancers, with its own surveillance including daily aspirin per NICE NG151 and gynae advice). Support the anxious young person, respect autonomy, and refer to clinical genetics; if the patient has bowel SYMPTOMS, assess and refer via the NICE NG12 pathway for symptomatic suspected colorectal cancer, with FIT where indicated — but an asymptomatic inherited-risk screening request follows the priority genetics pathway, not a suspected cancer pathway referral.