Anal Cancer
Symptoms, diagnosis and treatment information for anal cancer, including when to seek medical advice and what to expect from assessment and follow-up.
Anal cancer: symptoms, diagnosis and treatment
What is the anus?
The anus is the muscular opening at the end of the large bowel. The anal canal connects the anus to the rectum and is typically around 3–4 cm long.
How common is anal cancer?
Anal cancer is rare. Around 1,000 people are diagnosed each year in the UK. The most common type is squamous cell carcinoma.
Key message: Early diagnosis and treatment improve the chance of cure.
What causes anal cancer?
Several factors can increase risk, including:
- HPV (human papilloma virus)
- Sexual activity (risk is linked to anal HPV)
- Lowered immunity (e.g., immunosuppressive medicines or conditions such as HIV)
- Smoking
What are the symptoms of anal cancer?
- Bleeding from the anus
- Pain, discomfort and itching around the anus
- Small lumps around the anus (can be confused with piles/haemorrhoids)
- Difficulty controlling bowels (faecal incontinence)
- Mucus discharge
- Ulcers around the anus that can spread to buttock skin
Don’t wait. If you notice bleeding, persistent pain/itching, a new lump, or discharge, arrange an assessment—your GP can examine you and refer if needed.
How is anal cancer diagnosed?
Diagnosis usually starts with assessment and examination, followed by tests such as:
- Rectal (PR) examination
- Proctoscopy and biopsy
- Imaging including CT and MRI scans
- PET-CT in selected cases
- Endoanal ultrasound
What are the stages of anal cancer?
- Stage 1: smaller than 2 cm; limited to anus
- Stage 2: larger than 2 cm; no lymph node spread
- Stage 3: spread to nearby nodes and/or nearby organs
- Stage 4: spread to distant areas (e.g., liver)
How is anal cancer treated?
Treatment is usually led by a specialist team. The main approach is combined radiotherapy and chemotherapy (chemo-radiation). Surgery may be used in selected cases.
Will I need a colostomy?
Most patients treated for anal cancer do not need a colostomy. In some situations—such as persistent disease, recurrence, or unusual tumour types—more extensive surgery may be necessary.
What happens after treatment?
Side effects can occur for a time after treatment, but they often improve over months. Follow-up may continue for several years, and persistent symptoms can be referred for specialist support.
What do I do if I think I may have anal cancer?
Your GP is usually the best first step for assessment and referral. Private specialist assessment may also be available, including biopsy if appropriate.