What Do I Need to Know About HRA (High-Resolution Anoscopy)
If you’re concerned about your risk of anal cancer or have been advised to undergo High-Resolution Anoscopy (HRA), it’s important to understand what the procedure involves and why it matters.
This article explains what HRA is, who may benefit from it, and what to expect before, during, and after the procedure.
What is High-Resolution Anoscopy (HRA) and why is it important?
High-Resolution Anoscopy (HRA) is a specialised procedure used to examine the anal canal and perianal area for precancerous lesions and early anal cancer. It uses a magnifying instrument to provide a detailed view, essential to be able to detect and treatment of anal pre-cancer, also known as high-grade squamous intraepithelial lesions (HSIL) or ‘AIN’. The procedure is very similar to colposcopy, which aims to identify HSIL of the cervic. HRA is particularly important for high-risk populations in Melbourne, including men who have sex with men and people living with HIV, as early intervention can significantly reduce cancer progression.
Who needs an HRA?
People at high-risk of developing anal cancer should undergo screening, initially involving a digital anorectal exam (DARE) and swabs. If the results from this initial screen are positive, or if there is evidence of HSIL for other reasons (such as found on a haemorrhoid that has been removed), the next step is to perform a HRA.
High-risk groups include:
People living with HIV
Gay, bisexual and other men who have sex with men
Trans women
Individuals with a history of anal warts or HSIL
Anyone with a history of vulvar, vaginal, or cervical cancer or pre-cancer
If you fall into to any of these categories, it’s essential to discuss screening with your doctor. For more information of anal cancer screening, see Dr Marino’s blog ‘Anal Cancer – What Is It, Am I at Risk and Should I Be Screened?’.
Where is HRA performed?
HRA is most commonly performed in a clinic setting. A comfortable, dedicated clinic space ensures a smooth and comfortable patient experience. If clinic resources are minimal, HRA can also be carried out at the Hospital in an operating theatre. Mostly, it is carried out under local anaesthetic (so you are fully awake), but some patients will require a general anaesthetic (you are asleep). If this is the case, you will need to go to the operating theatre for your HRA.
What are you looking for in HRA?
During HRA, your anoscopist aims to identify anal high-grade squamous intraepithelial lesions (HSIL), which can lead to anal cancer. Removing these lesions helps prevent cancer development. Sometimes, early cancers are also identified. Since HSIL is almost always microscopic, magnification is crucial. We use acetic acid (weak vinegar) and Lugol’s iodine during the examination to highlight abnormal cells. Accurately identifying subtle changes suggestive of HSIL can be challenging, which is why becoming a skilled high-resolution anoscopist requires specialised training and experience.
What happens if you find something abnormal?
If an abnormality, such as HSIL, is detected during the HRA, your anoscopist will take a biopsy to confirm their suspicions. Depending on where the abnormality is, local anaesthetic may first be injected using a tiny needle (the same as what's used when you go to the dentist) so it is not painful, but you may still feel some pressure and discomfort. Results can take 2-3 weeks. We want to be sure what we are looking at is disease, before we go ahead and treat. If HSIL is confirmed, your anoscopist will notify you of your results and arrange to bring you back for a ‘treatment HRA’. The HRA is performed in the same way, but instead of taking biopsies, the diseased area is treated.
How do you treat pre-cancer (HSIL)?
Treatment for HSIL may involve several options, including topical therapies (creams) and ablative therapies like laser treatment or cauterization. Most commonly, we ablate (burn) the lesion (abnormal tissue) down to healthy layers, as HSIL only affects the top few layers of cells. If there’s concern that the lesion might contain early cancer, we may excise (cut out) the abnormal tissue. Topical therapies are almost never used on their own, but are good for shrinking down large areas of HSIL. The treatment approach will depend on the size, number, location, and extent of the lesions, and your anoscopist will explain the best course of action for your situation. Deciding on the best course of action can be difficult! This is why comprehensive training for high-resolution anoscopists is essential.
Will I need further HRAs?
Yes, if HSIL or other abnormalities are found, you will require follow-up HRAs to ensure the lesions are resolved. Due to the complex interplay between your immune system, HPV, and cell changes, HSIL can come and go. It’s not uncommon for some HSIL to remain within or near treated areas, or even appear in entirely new locations. Multiple HRAs may be needed to treat all HSIL, and even after treatment, new lesions can develop, making ongoing monitoring essential. Typically, a diagnostic HRA is performed six months after treatment. Depending on subsequent findings and other factors, the duration between HRAs may be increased.
What does the HRA procedure involve?
The HRA procedure begins with counselling and obtaining your consent. During the procedure, you’ll be positioned comfortably either with your legs up in stirrups or on your side, and a lubricated plastic tube (‘anoscope’) is placed in your anus and used to open skin folds within your anus to facilitate a thorough assessment. The colposcope is focused within your anus to give a magnified view. Once the anal canal is inspected, the area around the anus (perianus) is examined in a similar fashion but does not require the plastic tube. Suspicious lesions are biopsied in a diagnostic HRA, and biopsy-proven disease is treated in a treatment HRA. You can go home the same day after the procedure, once follow-up has been arranged.
If you’re concerned about your risk of anal cancer or think you may need an HRA, please consult your doctor. Dr Marino is an LGBTQIA+ friendly colorectal surgeon in Melbourne with specialised training in high-resolution anoscopy. He would be pleased to see you with a referral.
