Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.
2 min synopsisUK scopeSources checked 27 Aug 2026Clinical review pending
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Perianal sepsis, obstruction or major bleeding
Systemic toxicity from an abscess or fistula, necrotising infection, uncontrolled tumour haemorrhage, severe treatment enterocolitis or rare complete obstruction requires urgent resuscitation and source control.
Action: Use ABCDE care, provide analgesia, fluids, blood products and broad-spectrum antibiotics when infection is possible and obtain urgent colorectal, acute-oncology and radiology input for drainage or diversion that preserves later oncological options; do not delay sepsis treatment while obtaining cancer staging.
Synopsis
Recognise anal canal and margin cancer without attributing persistent symptoms to haemorrhoids, obtain sphincter-preserving tissue and site-specific staging and deliver definitive chemoradiation, delayed response assessment and salvage or metastatic care.
Most anal canal cancers are HPV-associated squamous-cell carcinomas and are biologically and therapeutically distinct from low rectal adenocarcinoma.
Persistent bleeding, pain, ulcer, lump, discharge, pruritus or continence change requires inspection, digital rectal examination and inguinal-node palpation; haemorrhoids do not close the differential.
The diagnostic reference standard is adequate biopsy, often during examination under anaesthesia, while preserving sphincter anatomy and avoiding an uncontrolled excision that compromises later treatment.
Key red flags
Persistent anal bleeding, pain, ulcer, lump, discharge, pruritus or change in continence requires digital and visual examination even when haemorrhoids are known.
Perianal sepsis
Fever, fluctuance, spreading erythema or crepitus requires immediate antibiotics and colorectal source control before detailed elective staging.
Investigation priorities
01
First-line anorectal and inguinal examinationFirst stepFirst line
Define site, size, fixation, sphincter relation, vaginal or prostate involvement and regional nodes before biopsy.
Management branches
Persistent symptomExamine before attributing to benign disease
Anal bleeding, pain, lump, discharge, pruritus or continence change persists or recurs.
Inspect perianal skin, perform digital rectal examination, proctoscopy and bilateral groin examination and assess sepsis, immune suppression and HPV-related history.
Arrange urgent colorectal assessment and biopsy under local or general anaesthesia, using drainage and antibiotics first when uncontrolled abscess or necrotising infection is present.
Key medicines
Mitomycin and capecitabine with radiotherapyA common UK radical protocol gives mitomycin 12 mg/m² intravenously on radiotherapy day 1, maximum 20 mg, plus capecitabine 825 mg/m² orally twice daily on each radiotherapy treatment day; use the exact centre protocol.
Carboplatin and paclitaxel for advanced diseaseA common 28-day regimen gives carboplatin AUC 5 intravenously on day 1 and paclitaxel 80 mg/m² intravenously on days 1, 8 and 15 for up to six cycles, modified for marrow, neuropathy and response.
National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.