High Resolution Anoscopy
What is High-Resolution Anoscopy?
High-Resolution Anoscopy (HRA) is a medical procedure used to closely examine the
bottom, known as the anus. It employs a specialized instrument called an anoscope,
which has a high-resolution camera attached, allowing for detailed visualization of the
area.
Why is HRA Performed?
HRA is typically performed to detect abnormalities in the anus and lower rectum, such as precancerous or cancerous lesions called squamous intraepithelial lesions (HSIL). It is commonly used for individuals at risk of anal cancer, including those with a history of human papillomavirus (HPV) infection, HIV, transplant surgery or a previous history of anogenital cancer or precancerous lesions.
How is HRA Done?
1. Preparation: Before the procedure, you can consider taking some paracetamol 30 minutes before your procedure.
Do NOT insert anything into your anus 24 hours before your HRA.
Do NOT use an enema or try to induce diarrhoea of any kind.
2. History: We will ask you questions about your health and ensure you understand the reasons for this examination. Any questions are welcomed.
3. Anal Cytology: We will first ask you to lie on your side on the examination table. A moist swab will be inserted in the bottom or anal canal to collect cells that will be examined under the microscope in the lab. This procedure lasts around 10 seconds.
4. Digital Rectal Examination: We will then examine the bottom or anus by inserting a lubricated finger to feel for any abnormalities.
5. HRA, Biopsy and Treatment:
◦ We will insert a gauze soaked in acetic acid (vinegar-like solution) into the bottom or anal canal and leave it in for 3-5 minutes. This stains any abnormal cells white and allows for the visualisation of abnormal pathology.
◦ We will then gently insert a lubricated anoscope (short plastic tube) into the bottom or anus to visualize the anal canal and lower rectum.
◦ A high-resolution camera magnifies the anal canal to detect any abnormalities in detail.
◦ If any suspicious lesions are identified, we will either take a biopsy under local anaesthetic (if not previously done). A biopsy involves removing a small piece of skin for testing.
◦ We may treat them with tri-chloroacetic acid (TCA) if you have already tried and failed treatment with either Aldara or 5-FU creams.
6. Aftercare: After the procedure, you may experience mild discomfort or minor bleeding. We will prescribe analgesia as required.
What are the benefits of HRA?
- Early detection of anal abnormalities, including precancerous and cancerous lesions.
- Precise visualization of the anal canal and lower rectum, allowing for accurate
diagnosis and treatment planning.
- Minimally invasive procedure with low risk of complications.
What are the risks and considerations of HRA?
While HRA is generally safe, there are some potential risks and considerations:
- Discomfort or minor bleeding during or after the procedure.
- Rarely, infection or injury to the anal canal or surrounding tissues.
- Biopsy-related risks, such as bleeding or infection from the bottom.
What is my follow-up?
Depending on the findings of the HRA, we may recommend further testing or treatment.
Regular follow-up appointments may be necessary to monitor any identified abnormalities or to assess the effectiveness of treatment.
Contact us
High-Resolution Anoscopy is a valuable tool for the detection and evaluation of anal abnormalities, particularly in individuals at high risk of anal cancer. If you have any questions or concerns about the procedure, don't hesitate to discuss them with us.
Contact Information: chelwest.anogenitaldysplasiaservice@nhs.net
References
1) Jay, Naomi. "High-resolution anoscopy: Procedure and findings." Seminars in Colon and Rectal Surgery. Vol. 28. No. 2. WB Saunders, 2017.
2) Palefsky, Joel M. "Practising high-resolution anoscopy." Sexual health 9.6 (2012): 580-586.
3) Brogden, D.R.; Lupi, M.E.; Warren, O.J.; Kontovounisios, C.; Mills, S.C. Comparing and contrasting clinical consensus and guidelines for anal intraepithelial neoplasia in diXerent geographical regions. Updates in surgery 2021, 73, 2047-2058.
4) Hillman, R.J.; Cuming, T.; Darragh, T.; Nathan, M.; Berry-Lawthorn, M.; Goldstone, S.; Law, C.; Palefsky, J.; Barroso, L.F.; Stier, E.A. 2016 IANS international guidelines for practice standards in the detection of anal cancer precursors. Journal of lower genital tract disease 2016, 20, 283-291
5) Lupi, Micol, et al. "Anal cancer in high-risk women: the lost tribe." Cancers 15.1 (2022): 60