Homerton Anogenital Neoplasia Service

Anal Intraepithelial Neoplasia

AIN is short for anal intraepithelial neoplasia and it is often referred to as ‘anal precancer’, as some forms of it can be serious, but, it is important to be clear that it is not cancer

• Neoplasia: microscopic cell changes seen as cells undergo the process of becoming cancerous
• Intraepithelial: the abnormal cells have not got further than the epithelium or the lining of the anus

If you have been told you have AIN it is likely that it has been found due to a biopsy that has been taken, on an anal smear test, or, on looking with a microscope at the peri-anus (the skin around the anus) and the anal canal.

What causes AIN?
In 90% of cases, AIN is linked to infection with the human papillomavirus (HPV). HPV infection is extremely common. Not everyone who comes into contact with the HPV virus will get AIN. HPV virus also causes warts. Not everyone who has had warts will develop AIN.

Why do some people infected with HPV get AIN and some do not?
Not everything is known yet about AIN.
We know that immunosuppression of any kind weakens the body’s defences against the HPV virus and makes AIN more likely, often some years later. This includes

• HIV infection (even if well-controlled)
• Organ transplants
• Inherited immune defects
• Immune-suppressing drugs 

AIN is more common in those who practise receptive anal sex, especially men who have sex with men (MSM), and are HIV positive. Smoking is a known risk factor for AIN and anal cancer. However, some people have AIN without any risk factors.

It is hoped that the HPV vaccine will eventually make AIN rare, however as far as we know at present, once you have been infected with HPV (which most sexually active people have been), the vaccine will not work to treat or prevent AIN.

How should AIN be treated?
A study (ANCHOR) was reported in 2022 and it  concluded that actively treating anal AIN/HSIL significantly reduced the chance of progression to anal cancer .

At present, we suggest

1. If you have low-grade AIN then you do not need treatment. We will suggest that testing is repeated in the future.
2. If you have high grade AIN or HSIL then we will suggest follow up with assessments including HRA.
3. For persistent areas, and wide areas of AIN, topical treatment can be used: imiquimod (Aldara), Catephen and 5 fluorouracil (5FU) are all types of cream (creams you apply yourself) that can be prescribed for use for 3-4 months. This treatment is most successful for AIN on the external skin.
4. In certain cases TCA (Trichloroacetic Acid) treatment is offered. It is painted on to the treatment area in clinic by one of the doctors or nurses, over several visits.
5. In some cases, laser ablation of the AIN/HSIL is suggested. The ANCHOR study has confirmed that actively treating AIN/HSIL with methods such as laser is more likely to prevent anal cancer than just close observation.

Referral
Patients are referred to the HANS service by a specialist and occasionally their GP. At present, it is not possible for people to refer themselves to the service. 

Assessments
Once a referral is made, then the patient is contacted with an appointment for an assessment. Every effort is made to see patients for assessment at the earliest possible time.

The patient is sent an appointment date and time. If it is not convenient then a new appointment can be made, but this may be some time later.

During the assessment appointment, the doctor will ask questions about the patient's medical history and will make an examination. If necessary, the doctor will take biopsies for a specific diagnosis. 

Your next appointment
Following the assessment appointment and possible biopsies, there will be a gap of 4-8 weeks. During this time the clinicians review the assessment and biopsy results and decide on the next stage. There are 3 possible outcomes:

1. The patient is discharged: The doctors have reviewed the examination results and decided that there is no need to return.
2. The patient may be put on surveillance: The doctors have reviewed the examination results and decided that they would like to keep an eye on the patient who is sent an appointment, usually for 6 months later.
3. The doctors have reviewed the examination results and decided that the patient should be offered treatment. The clinician will contact the patient and explain the treatment that is recommended and an appointment is made. There are different kinds of treatments and the clinician will explain the recommended treatment.

More detailed information about the HANS service, the methods of examination and forms of treatment, is available from the menu below.

High resolution anoscopy, or HRA, is a procedure that allows for examination of the anal canal and surrounding skin using a microscope similar to a colposcope (used in the examination of the neck of the womb). This procedure is used to check for abnormal cells that have a higher likelihood of turning into cancer.

HRA is an outpatient procedure. It is usually well tolerated with only mild, if any discomfort. The microscope/colposcope provides magnification of up to 40 times. With it, the clinician performing the exam can detect any abnormal cells.

Taking a biopsy
After careful and thorough examination, the clinician may decide to take a biopsy. This is a small sample of tissue (4mm size) that is sent to the laboratory for analysis. A local anaesthetic will be given before the biopsy to minimise any discomfort. Healing of the biopsy sites occurs over 4-7 days, usually without any scarring.

Biopsy results
Once the clinicians receive the biopsy results, they will send you a letter and a copy to your GP.  If they have suggested treatment, then the HANS office will write to you with an appointment.

The High Resolution Multi-Zonal procedure

We ask you to remove the lower half of your clothes and you are given a gown. 

Before examination of the ano-genital skin the clinician will perform an anal cytology test (smear test) . This involves gently inserting a fine thin brush into the anal canal to obtain cells from the lining of the anus to be looked at under a microscope. 

High resolution examination of the ano-genital skin uses a microscope to visually highlight areas of disease in the anatomical zones. 

A cotton swab covered with mild (5%) acetic acid will be applied to the genital zones.

The acetic acid on the cotton swab will cause any abnormal cells to turn white; these are called ‘Acetowhite’ areas.  

The colposcope provides magnification of up to 30 times. With it, the clinician performing the examination can detect any abnormal cells (areas) 

Should you wish, you can watch what is happening on the screen.  All procedures are performed using sterile or single-use equipment   

The genital zones 

The clinician will begin the multi-zonal high resolution assessment by examining all the genital zones. 

Following detailed examination of the external zones the clinician will insert a lubricated speculum to assess the vaginal canal and cervix if indicated. 

The clinician may perform a cervical cytology ‘pap smear’ at this point in the examination depending on your cervical screening history. 

Acetic acid will then be applied. Using magnification provided by the colposcope, your clinician will carefully check for patterns that appear when abnormal cells present. When the cells change from their normal colour to a white colour this is known as  “acetowhite change”. 

In addition to examining inside the vagina, the external vulval skin and peri-anal skin is also examined with application of additional acetic acid using the colposcope. 

Digital anorectal examination; DARE. 

When examining the anus, the clinician will firstly examine the anal canal with a finger to feel inside for any lumps or abnormal features. They will also examine the skin around the anus for any abnormalities 

A thin hollow tube called a proctoscope will be coated with a lubricant mixed with anaesthetic cream (Emla) and inserted about two inches into the anus to enable examination of the anal canal. 

The procedure is usually very well tolerated with mild, if any, discomfort. Significant risks such as bleeding or infection are extremely rare. If you do feel discomfort the clinician is also able to provide ‘gas and air’ as required. 

Taking a biopsy

After careful and thorough examination, the specialist may recommend that a biopsy is taken(a small sample of tissue that is sent to the laboratory for analysis). 

 A local anaesthetic will be injected before the biopsy is taken to help minimize any discomfort.A brown solution (Monsel’s) may be applied to the biopsy site after removal to stop any minimal bleeding.

The tissue sample removed during the biopsy will then be sent to a pathologist for further examination. 

In three to four weeks the specialists will contact you with your results and decide on possible treatments or further follow up. At this point a letter is sent out to you and a copy to your GP / Referring doctor.  

HPV stands for the human papillomavirus. It is a very common virus that is spread by direct contact, and infects skin cells and moist membranes that line different parts of the body, including the mouth, throat and genital area.

There are over one hundred types of HPV and about 40 of these can affect the genital area. Some types of HPV can cause skin warts and verrucas but many types do not cause any problems or harm at all

Most adults get HPV at some point in their lives, and in most cases your body will get rid of the virus without you ever knowing you had it. However, HPV is also linked to the development of abnormal cells. If left untreated, these abnormal cells may go on to develop into cancer.

What are the symptoms of HPV, anal warts and anal dysplasia? 

• Patients with “dormant” HPV infection or a small number of anal warts usually have no symptoms. Other patients may notice small growths in the anal area that may increase in size or number. They may experience anal itching, burning or tenderness, anal bleeding, or anal discharge. In some patients, the warts may become very large and cause pain, significant discharge and odour, or interfere with the ability pass bowel movements.
• In men, genital warts mainly appear on the penis and scrotum.
• In women, they tend to be seen on the vulva, vagina and cervix.
• Both sexes may be affected in the perineum, around the anal area and inside the anal canal.

How is HPV treated?
There are three main treatments for HPV related disease: chemical destruction, immune therapy, and surgical treatment. The clinician will advise the best treatment based upon their examination and the biopsy results.

It is important to realise that regardless of the treatment, recurrence of HPV is common. Skin cells outside of the visible area of disease may already be infected and not be detectable until new warts form. 

Is there an HPV vaccine?
At the time of writing,  the Gardisil 9 vaccine, protecting against 9 HPV types, has replaced Cervarix and the original Gardisil. HPV vaccination is part of the national vaccination programme and is currently given to girls and boys around the age of 12 years.

If you missed your vaccination at school -you remain eligible to receive the vaccine up until your 25th birthday.

The HPV vaccine is also available to:

• Men who have sex with Men (MSM) up to and including 45 years of age 
• Some transgender individuals; sex workers; men and women living with HIV infection

contact your local sexual health clinic or GP for more details.

HPV vaccine - NHS

What is a biopsy and how is it taken?

A biopsy is a tiny sample of tissue taken from the body. At Homerton Anogenital Neoplasia Service you may be recommended to have a biopsy at the time of your assessment to find out more information and to plan correct treatment for your condition. Biopsies may be needed from the anus, peri-anal skin, vulva, vagina or cervix. You will be asked if you are happy to go ahead with a biopsy. If you are concerned or do not wish to have a biopsy, please discuss this with the clinician assessing you.

We will give you local anaesthetic to numb the skin before the biopsy. After the biopsy there will be a small amount of bleeding. We use Monsel’s solution or silver nitrate to stop the bleeding. Rarely, a stitch is needed.

Biopsy samples are sent to the laboratory for further analysis.

What happens after a biopsy? 

After a biopsy:

• The local anaesthetic wears off after 30-60 minutes. You can take simple pain killers such as paracetamol.
• You should rest following the biopsy. Light exercise may continue but avoid heavy work and exercise for a few days or until the area has healed.
• You can expect some discomfort, light bleeding, mild discharge and sometimes some localised swelling and bruising. 
• Please contact the nursing team (020 8510 5296) or your GP if you experience:
  • heavy bleeding or bleeding that doesn’t stop after a week
  • discharge with an unpleasant smell
  • a fever, feel unwell or develop a temperature higher than 38C
  • increasing pain/bruising
  • a very painful, very hot, very red and swollen wound

For urgent advice if you feel very unwell you can attend your local Emergency Department

Aftercare:

• Avoid sex for 1 week, or until comfortable (which could be as early as 48 hours later UNLESS you have had a vaginal biopsy when you should wait 1 week).
• For external biopsies, it can sooth the area to sit in a warm bath with a tablespoon of salt in the bathwater (sitz bath).
• You may shower as usual, but do not linger in the bath or add bubbles. Keep the area dry and clean. Gently pat the affected skin dry – do not rub vigorously. Avoid perfumed products until the area has healed.
• Swimming can be resumed once the biopsy site has healed.
• You can usually return to all your normal activities and work straight away or as soon as you feel well enough. You should discuss this with your nurse or doctor.

If you have had an anal/perianal biopsy:

• Keep your poo soft by eating a high fibre diet and drinking extra fluids. You should aim to open your bowels regularly.
• You may feel like you need to pass poo or keep going to the toilet. These are normal sensations and are usually mild. 

When will I get my results? 

It usually takes 4-6 weeks. We will write to you and your GP with the results and a recommended follow-up plan.

 Who can I contact for more information? 

If you have any further questions or concerns, please contact the clinic on 020 8510 5296 or email our administration team at:  huh-tr.hanshomerton@nhs.net 

HRA-HPV-AIN

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