Synopsis
Recognise symptomatic and screen-detected colorectal cancer, use FIT without delaying red-flag assessment, obtain complete colonoscopic histology and site-specific staging and coordinate endoscopic, surgical, radiation, systemic, genetic and survivorship care.
- Right-sided cancer commonly produces iron-deficiency anaemia, fatigue and vague pain; left-sided disease more often causes altered habit and obstruction, and rectal cancer causes bleeding, urgency and tenesmus.
- Use quantitative FIT to triage appropriate symptomatic patients, but a low result does not overrule a rectal or abdominal mass, persistent unexplained symptoms, iron deficiency or strong clinical concern.
- The diagnostic reference standard is complete colonoscopy with biopsy, careful lesion localisation and assessment for synchronous neoplasia; CT colonography is the principal alternative when colonoscopy is incomplete or unsuitable.
Key red flags
Peritonism, fever, shock, free air or rapidly worsening abdominal pain suggests perforated cancer and needs emergency surgery and antibiotics.
Absolute constipation, marked distension, faeculent vomiting, peritonism, sepsis or free air requires urgent CT and colorectal surgical care.
Investigation priorities
Measure faecal haemoglobin to prioritise colorectal investigation in adults with compatible lower-GI symptoms.
Stage liver, lung, peritoneal, nodal and locally invasive disease and identify potentially resectable metastases.
Management branches
An adult has rectal bleeding, altered bowel habit, iron deficiency, weight loss or compatible abdominal symptoms.
- Assess haemodynamic state, obstruction, abdominal and rectal masses and full-blood-count evidence of iron deficiency, activating emergency care when unstable.
- Request quantitative FIT where appropriate and refer at the current threshold, but refer or investigate persistent red flags and masses regardless of a low result.