Chapter 07 — Anal Cancer, Anal Intraepithelial Neoplasia, and Non-Healing Anorectal Lesions

Purpose: any anorectal lesion that is indurated, ulcerated, bleeding, persistent, or recurrent is a possible cancer until a biopsy says otherwise — this chapter shows how to recognise it, whom to refer, and how fast.

🎨 INFOGRAPHIC / VISUAL BLUEPRINT — CHAPTER 07

• Chapter colour palette: Deep Rose (#9D174D) header bar, Blush (#FDF2F8) panels, Graphite (#1F2937) text.
• Hero graphic: Anal canal map showing the anal margin, the anal canal, and the transformation zone at the dentate line, with tumour types placed where they arise (squamous cell carcinoma, adenocarcinoma, melanoma), plus a horizontal “LSIL → HSIL → cancer” ladder and a large “4–6-week review” clock.
• Icon set: Magnifier, biopsy punch, HPV virion, shield (HPV vaccine), red ribbon (HIV), crossed-out cigarette, lymph-node cluster (groin), calendar with review date.
• Bedside aphorism banner: “If it is hard, ulcerated, or not healing, it is not “just piles” — biopsy it.”

1. Anal and Perianal Malignancies at a Glance

Anal cancer is uncommon in the general population, but its incidence is much higher in defined risk groups, and it is often diagnosed late because early symptoms — bleeding, pain, itch, a lump — are attributed to haemorrhoids or fissure.

Table 7.1 — Anal and perianal malignancies

2. Anal Intraepithelial Neoplasia — the Modern Terminology

The Lower Anogenital Squamous Terminology (LAST) system uses two tiers for HPV-related precursor lesions. Older terms still appear in reports and referral letters.

Table 7.2 — Squamous intraepithelial lesions

ℹ️ EVIDENCE HIGHLIGHT

Why this matters now [S]: in the ANCHOR randomised trial (Palefsky et al. 2022) of people living with HIV with biopsy-proven anal HSIL, treating HSIL reduced progression to anal cancer by 57% compared with active monitoring. This result underpins current screening recommendations for high-risk groups.

3. Who Should Be Offered Anal Cancer Screening (IANS 2024) [C]

The International Anal Neoplasia Society set screening start ages using anal cancer incidence thresholds. Screening uses anal cytology, high-risk HPV testing (with HPV 16 genotyping), or co-testing, together with a digital anal–rectal examination (DARE). Abnormal results lead to HRA. Availability of HRA varies widely between countries; follow local pathways [L].

Table 7.3 — Screening start points (IANS 2024)

Where HRA is not available, many programmes rely on regular DARE to detect early cancers in high-risk groups [C][L]. Screening is for people without symptoms — any symptomatic patient follows the diagnostic pathway in section 5, not the screening pathway.

4. Red-Flag Checklist for Non-Healing Perianal and Anal Lesions

Any single item below means an urgent specialist referral and a biopsy — not another cream.

5. Why Persistent Lesions Must Not Be Labelled “Haemorrhoids”

• Haemorrhoids are soft, compressible, and painless unless thrombosed; they do not ulcerate for weeks, become hard, or cause enlarged groin nodes.

• Treatments for “piles” can hide a cancer: steroid and anaesthetic creams improve symptoms temporarily, while banding, cautery, or excision without histology can delay diagnosis or compromise curative chemoradiotherapy.

• NICE NG12 (with DG56): an unexplained anal mass or unexplained anal ulceration warrants consideration of a suspected-cancer pathway referral, and does not need a faecal immunochemical test (FIT) first [S].

6. Safe Examination, Biopsy, and the Referral Pathway

Table 7.4 — From the first examination to the MDT

7. HPV Vaccination and Prevention

• HPV vaccination [S]: routine vaccination at age 11–12 (can start at 9), catch-up through age 26, and shared decision-making for adults aged 27–45 (ACIP 2019). WHO (2022) permits one- or two-dose schedules in young people, but recommends at least two, and ideally three, doses for people who are immunocompromised, including those living with HIV. National programmes differ — follow your national schedule [L].

• Stop smoking: smoking increases persistence of HPV infection and anal cancer risk.

• HIV care: effective antiretroviral therapy and regular review; screening as in Table 7.3.

• Condoms reduce, but do not eliminate, HPV transmission.

Algorithm 7.1 — Non-healing or suspicious anorectal lesion

[ANAL OR PERIANAL LESION: ULCER, MASS, PLAQUE, OR "PILE"]
|
+-- Inspect + palpate + DRE + anoscopy + check BOTH groins
|
+-- ANY RED FLAG? induration, heaped edge, mass, contact
|   bleeding, pigment, lateral/painless ulcer, groin nodes,
|   chronic fistula with new mass or mucus, high-risk patient
|     -> YES: URGENT suspected-cancer referral (no FIT needed)
|        do NOT band, excise, or cauterise; offer HIV test
|        record size, site, distance from the verge
|        -> specialist biopsy / EUA -> MRI pelvis + CT
|           (or PET-CT) -> MDT
|
+-- No red flag and a benign cause is clear
|     -> treat it (fissure, haemorrhoid, dermatitis, wart)
|     -> REVIEW at 4-6 weeks
|        +-- healed -> discharge with safety-net advice
|        +-- not healed, recurred, or changing
|              -> treat as a RED FLAG: urgent referral
|
+-- High-risk person with NO symptoms (HIV, transplant,
    prior vulvar HSIL/cancer, MSM or TW)
      -> offer screening per IANS 2024 where available
         (cytology and/or hrHPV + DARE) -> HRA if abnormal

8. Dangerous Mimics

Table 7.5 — Benign-looking lesions that may be malignant

9. Role-Targeted Action Boxes

🚑 ER DOCTOR ACTION BOX

• Do not discharge an ulcerated or indurated anal mass as a “thrombosed pile”. Document size, site, and groin nodes; refer urgently with a named follow-up route.
• Tumour emergencies: heavy bleeding (resuscitate, direct pressure, surgical review), obstruction, perforation, or an abscess around a tumour — same-day surgical review; send drained tissue for histology.
• Offer an HIV test when anal cancer or HSIL is suspected.

🩺 FAMILY MEDICINE / GP CLINIC BOX

• Apply the 4–6-week rule: any anal lesion treated as benign must be re-examined; if it has not healed, refer urgently for biopsy.
• Refer an unexplained anal mass or ulcer on the suspected-cancer pathway — no FIT needed (NICE NG12/DG56).
• Ask about previous cervical, vulvar, or vaginal HPV disease, HIV, transplant, and smoking. Check cervical screening and HPV vaccination status.

🏥 ER & WARD NURSE CARE AND SBAR BOX

• Safety-net and track: give the patient a written review date; confirm urgent referrals and biopsy results are received and acted on.
• Communicate with care: offer a chaperone, explain each step, and signpost psychological and cancer-nurse support once a diagnosis is made.

💊 CROSS-SPECIALTY PRESCRIBING TRAP

• Repeat prescriptions of haemorrhoid creams without re-examination can mask cancer for months.
• Immunosuppressants (transplant, biologics) increase the risk of persistent HPV disease; such patients need a lower threshold for examination and referral.

⛔ NEVER DO THIS

• Never band, cauterise, or excise a suspicious anal lesion without histology.
• Never call an ulcer that has not healed after 6–8 weeks a “chronic fissure” without specialist review.
• Never forget the groins — inguinal nodes change staging and urgency.
• Never omit an HIV test in a patient with anal SCC or HSIL.

📝 COMMON DOCUMENTATION ERROR

• “Haemorrhoids” recorded for a firm 3 cm lesion, with no size, site, distance from the verge, or nodal examination.
• No safety-net date and no record of who will chase the biopsy result.

📨 REFERRAL URGENCY BOX

The Patient in Front of You — Chapter 07 Mini-Case

🧑‍⚕️ THE PATIENT IN FRONT OF YOU

A 52-year-old woman has had “piles” for 6 months, treated with three different creams. She now has bleeding and pain on sitting. She was treated for cervical intraepithelial neoplasia grade 3 ten years ago and smokes 15 cigarettes a day. On examination there is a 2 cm indurated ulcer with heaped edges at the left lateral anal margin, and a firm 1.5 cm left inguinal lymph node.

Step 1 Recognise the red flags: induration, heaped edge, lateral ulcer, groin node, and a history of HPV-related cervical disease.

Step 2 Do not treat as haemorrhoids: stop the creams; no banding or excision.

Step 3 Refer urgently on the suspected-cancer pathway with size, site, distance from the verge, and nodal findings documented; offer an HIV test; check cervical screening.

Step 4 Expected pathway: specialist biopsy confirms SCC; MRI pelvis and CT or PET-CT stage the disease; the MDT plans chemoradiotherapy; smoking-cessation support begins now.

Board-Style Question — Chapter 07

A 41-year-old man who has sex with men and has lived with HIV for 12 years (undetectable viral load on antiretroviral therapy) asks about anal cancer prevention. He has no anal symptoms and a normal examination. What is the most appropriate advice?

• A. No screening is needed unless symptoms develop
• B. Offer anal cancer screening now (anal cytology and/or high-risk HPV testing with a digital anal–rectal examination), with high-resolution anoscopy if abnormal
• C. Colonoscopy every 5 years from now
• D. Annual serum CEA measurement

Answer and explanation

• ❌ A Waiting for symptoms misses the window to treat HSIL before it becomes cancer.
• ✅ B Correct. IANS 2024 recommends starting screening at age 35 for MSM and transgender women living with HIV. The ANCHOR trial showed that treating HSIL reduces progression to anal cancer by 57%.
• ❌ C Colonoscopy screens for colorectal neoplasia and does not assess the anal transformation zone adequately for HSIL.
• ❌ D CEA is not a screening test for anal cancer.

Ten-Item Rapid Revision Checklist — Chapter 07

• 01 I know anal SCC is HPV-related and usually treated with chemoradiotherapy, not surgery.
• 02 I can name the main risk groups: HIV, MSM, transplant, prior HPV-related cancer or HSIL, smoking.
• 03 I use LSIL/HSIL terminology and know HSIL is the true precursor.
• 04 I know the IANS 2024 screening start ages.
• 05 I apply the red-flag checklist to every non-healing lesion.
• 06 I review every “benign” anal lesion at 4–6 weeks.
• 07 I examine both groins.
• 08 I never band, cauterise, or excise a suspicious lesion without histology.
• 09 I offer an HIV test when anal cancer or HSIL is suspected.
• 10 I promote HPV vaccination according to the national schedule.

Five Most Dangerous Mistakes — Chapter 07

1. ⚠️ Repeating haemorrhoid creams for months for an indurated ulcer.
2. ⚠️ Excising a “pile” that is actually an anal cancer, without histology.
3. ⚠️ Missing inguinal nodes because the groins were not examined.
4. ⚠️ Treating a non-resolving “thrombosed pile” conservatively and missing melanoma.
5. ⚠️ Failing to track an urgent referral or biopsy result.

Suggested Figure and Table Captions for the Medical Illustrator — Chapter 07

• Figure 7.1. Anal canal anatomy: anal margin, anal canal, and transformation zone, with sites of SCC, adenocarcinoma, and melanoma.
• Figure 7.2. Clinical appearance: benign chronic fissure versus indurated ulcerating anal SCC.
• Figure 7.3. The LSIL → HSIL → SCC ladder with LAST terminology.
• Figure 7.4. Groin examination for inguinal lymph nodes.
• Table 7.1. Anal and perianal malignancies.
• Table 7.2. Squamous intraepithelial lesions.
• Table 7.3. IANS 2024 screening start points.
• Table 7.4. From the first examination to the MDT.
• Table 7.5. Benign-looking lesions that may be malignant.
• Algorithm 7.1. Non-healing or suspicious anorectal lesion.