Anal squamous cell carcinoma is HPV-related (types 16 and 18 in 80–90% of cases) and its incidence is rising — particularly in HIV-positive MSM where the risk is 80-fold higher than the general population. It typically presents as a perianal lump, ulcer, or persistent pain, and is often misdiagnosed as a haemorrhoid, fissure, or wart for months. Treatment is with the Nigro chemoradiotherapy protocol (5-fluorouracil + mitomycin C + radiotherapy) — 80% 5-year survival with localised disease, falling to 30% with metastatic disease. Early diagnosis is therefore critical. Any suspicious perianal lump that does not clearly have a benign explanation should be biopsied or referred for colorectal assessment.

The distinction between a prolapsing haemorrhoid and a rectal prolapse is clinically important and sometimes missed. Haemorrhoids prolapse as separate cushions with radial folds; full-thickness rectal prolapse produces a single large, fleshy, concentric-ringed structure. Rectal prolapse is associated with significant pelvic floor weakness — often in elderly multiparous women or those with neurological conditions affecting the pelvic floor. It requires colorectal surgical assessment. Grade III and IV haemorrhoids (requiring manual reduction or permanently prolapsed) also require colorectal referral for banding or haemorrhoidectomy — they cannot be managed conservatively indefinitely. Haemorrhoid grading: Grade I — bleed only; Grade II — prolapse + spontaneous reduction; Grade III — prolapse + manual reduction needed; Grade IV — permanently prolapsed, irreducible.

Condylomata acuminata (genital and anal warts) are caused by HPV — most commonly low-risk types 6 and 11. However, high-risk types (16, 18) can co-infect or be present separately, and anal warts require GUM referral for HPV typing, treatment, and anal cancer surveillance rather than simple topical treatment by the GP. In HIV-positive patients, warts are often more extensive, more rapidly growing, and more likely to harbour high-risk HPV. Imiquimod 5% cream (self-applied BD 3 nights/week × 16 weeks) is effective for external warts — it is an immune response modifier, not a cytotoxic agent. Podophyllotoxin 0.15% cream (Warticon) or 0.5% solution — applied BD × 3 days, 4 days rest, repeat × 4–5 cycles. Neither should be used inside the anal canal — internal warts require specialist treatment.

Examination with straining (the Valsalva manoeuvre) is essential for assessing anal lumps — haemorrhoids and rectal prolapse may not be visible at rest but become apparent with increased intra-abdominal pressure. The most effective way is to examine the patient on a left lateral position and ask them to bear down as if opening their bowels. Alternatively, a commode examination is even more effective — the patient sits on the commode, strains, and the examiner inspects from behind. This simple manoeuvre can reveal Grade III/IV haemorrhoids and rectal prolapse that would be invisible at rest. Many GP examinations miss prolapsing lesions because straining is not incorporated into the examination.

Rubber band ligation (banding) for Grade II–III haemorrhoids is one of the most effective and cost-efficient outpatient procedures in colorectal surgery — 80% success rate, minimal recovery time, can be performed in an outpatient setting without anaesthesia. It works by placing a tight rubber band at the base of the haemorrhoidal cushion above the dentate line (painless region), causing ischaemia and fibrotic obliteration of the haemorrhoid within 7–10 days. GPs should refer Grade II–III haemorrhoids to colorectal for banding rather than managing indefinitely with topical creams — creams treat symptoms only and do not address the underlying haemorrhoidal tissue. HALO (Haemorrhoidal Artery Ligation Operation) — Doppler-guided arterial ligation — is increasingly used for Grade III–IV haemorrhoids as an alternative to haemorrhoidectomy with faster recovery.

The 72-hour rule for thrombosed external haemorrhoid (TEH) is an important clinical decision point — before 72 hours, surgical excision (not simple incision) dramatically reduces pain, swelling, and time to resolution, and can be performed under local anaesthesia. After 72 hours, the oedema surrounding the thrombus makes surgical access more difficult and the risk of incomplete excision and residual skin tag increases. The spontaneous resolution trajectory means most TEHs resolve over 2–3 weeks conservatively. GPs who see a TEH within 72 hours should refer urgently for same-day surgical excision — this is a simple, highly effective intervention that provides immediate relief. Warning the patient that it will hurt for 2–3 weeks if managed conservatively is an important part of informed consent.

The Nigro chemoradiotherapy protocol (originally described in 1974) cures 85% of anal SCC without surgery — this is remarkable given that abdominoperineal resection (which removes the entire anus and creates a permanent colostomy) was the only treatment previously. The key insight was that anal SCC, unlike colorectal adenocarcinoma, is a radiosensitive tumour that responds excellently to combined chemoradiotherapy. GPs should be aware of this because patients often fear they will need a colostomy — reassuring them that the primary treatment is non-surgical and that surgery is reserved for non-responders is an important part of communication. The main acute toxicities are radiation proctitis and skin desquamation — GPs manage these supportively with barrier creams, sitz baths, analgesia, and stool softeners.

Gardasil 9 is now available on the NHS for MSM up to age 45 years via GUM clinics — this is a significant public health intervention given the 80-fold increased anal cancer risk in HIV-positive MSM. GPs should check HPV vaccination status in all MSM patients and direct them to GUM for vaccination if not completed. Even in already sexually active individuals, vaccination provides benefit against HPV types they have not yet been exposed to. The U=U (Undetectable = Untransmittable) principle for HIV is scientifically robust — the PARTNER and PARTNER2 studies demonstrated zero HIV transmissions in couples where the HIV-positive partner was on effective ART with an undetectable viral load. GPs communicating this to patients reduces stigma and improves HIV medication adherence.

Anal warts that do not respond to two standard treatment cycles must be biopsied — treatment failure may indicate the presence of high-risk HPV, early Buschke-Löwenstein tumour (giant condyloma — locally invasive but rarely metastatic), or anal intraepithelial neoplasia (AIN) progressing towards anal SCC. Buschke-Löwenstein tumour presents as a very large cauliflower-like perianal mass and can be confused with a large condyloma acuminatum — it is locally destructive and requires surgical excision. Any condyloma acuminatum that is unusually large (>2 cm), rapidly growing, or causing functional symptoms should be referred urgently rather than treated empirically.