Anal Intraepithelial Neoplasia (AIN)

AIN is often asymptomatic. However, when symptoms are noticeable, they can include:

• pain in your anus

• an itchy anus

• bleeding from your anus

• changes in the skin around your anus

It can sometimes be found in warts and other presumed benign skin tags or haemorrhoids and lesions, both in your anal canal or on the skin around your anus.

AIN is caused by exposure to HPV, an infection that’s passed through sexual contact. 

There are more than 100 strains of HPV, most of which are harmless. The virus often clears up on its own and doesn’t need treatment. However, there are a few types that can increase your risk of developing AIN if your body doesn’t clear them and they remain in your body. 

In women, the cause of AIN is similar to cervical changes (cervical intraepithelial neoplasia or CIN) detected on cervical smear tests. 

Risk factors

High-risk populations for this condition are:

• anyone who’s had genital warts at any time in their life

• men who have sex with men (MSM)

• people with immune suppression related to HIV

• people who’ve previously had an organ transplant

• people with inflammatory bowel disease (IBD)

• people who use steroids

• women who’ve had previous abnormal cervical screenings/smear tests

Your consultant will see you for an initial consultation. At this appointment, they’ll ask you about your medical history and symptoms, if you have any. A physical examination may be needed so they can check for any visible changes in your skin.

They’ll also need to run a test to confirm or rule out AIN. The test is called high-resolution anoscopy (HRA). In an HRA, your anal canal and rectum are examined using an anoscope (a small tube, around 5 inches long and the width of a finger). Your consultant will use a second device called a colposcope to closely examine the area. The test is the gold standard for diagnosis and surveillance of AIN in people who are at risk.

The test is essential for your consultant to make an accurate diagnosis and recommend the most effective treatment for you.

You can’t fully protect yourself against HPV, but you can follow these steps to try to reduce your risk:

1. Get the HPV vaccine if you’re eligible.

2. Use a condom or a dental dam during sex.

3. Have regular STI tests.

4. Stop smoking.

Remember that AIN is not cancer. And most cases of AIN don’t develop into cancer. Up to 25% of AIN cases clear up over time. But in some people, AIN will persist, probably due to a persisting HPV infection. Approximately 9% to 10% of people with AIN may progress to anal cancer.

Your consultant will tell you whether you’re at risk, and if so, whether you’ll need treatment to prevent or slow the progression of the abnormal cells.

However, if you have AIN and don’t seek treatment, it can develop into anal cancer.

Your treatment options will depend on your situation and the grade of your abnormal cells. AIN can be split into 3 grades:

• AIN I: slightly abnormal cells

• AIN II: moderately abnormal cells

• AIN III: severely abnormal cells

Monitoring

If you’re diagnosed with AIN, your consultant may enter you into a surveillance programme to monitor and treat the AIN to ensure it doesn’t progress to anal cancer. Surveillance may also involve taking small biopsies (samples) of the area affected at regular intervals.

Topical treatments

You may be recommended topical treatments such as Imiquimod, Cidofovir and 5-Fluorouracil. Ablative treatments such as electrocautery, laser therapy and radiofrequency ablation are also an option to treat AIN.

Vaccination

If you’ve been diagnosed with a type of HPV that’s associated with AIN, you may be considered for vaccination against multiple strains of HPV.

At Welbeck, our colorectal specialists are experts in their field and are dedicated to providing world-class care to every patient.

With access to colleagues across other specialties, our consultants are also able to refer within the Welbeck ecosystem if required to ensure you receive the treatment you need as quickly as possible, all under one roof.  

All appointments, testing, treatment, and follow-up appointments take place within our state-of-the-art facilities, enabling us to deliver accurate diagnostics and advanced treatments.

Your health is important to us, so we strive to offer same-day appointments whenever possible.

Our consultants are recognised by the major health insurance companies. If you have private health insurance, your treatment at Welbeck can begin once you have obtained authorisation. We also provide care to self-paying patients. Learn more about the different payment options at Welbeck.

Get in touch today to book an appointment.