HIV-positive men who have sex with men (MSM) are the main risk group for anal cancer. The abnormalities in the tissue are generally caused by the Human Papilloma Virus (HPV): a sexually transmitted virus.
It is generally assumed that screening for and treatment of Anal Intraepithelial Neoplasia (AIN) can prevent the development of anal cancer. In practice, these precancerous stages are called Anal Intraepithelial Neoplasia (AIN). Treatment depends on the stage of AIN, with numbers indicating the severity of the abnormality. To increase the chance of early detection, MSM HIV patients are invited to the AIN consultation hour.
AIN screening
AIN stands for: Anal Intraepithelial Neoplasia. This means that there is a preliminary stage of anal cancer. During AIN screening, we screen for precancerous anal cancer. This is done using High Resolution Anoscopy (HRA), a combination of proctoscopy and colposcopy, in which a camera that creates very detailed images of the mucous membranes of the rectum, the anal canal and the perianal region is inspected. Deviations can be detected here. During the examination, biopsies are taken of these abnormalities, which are assessed by the pathologist anatomist. The result is graded in: no abnormality, AIN 1, AIN 2 and AIN 3, respectively mild, moderate or severe dysplasia.
If no abnormality is found, someone will be re-screened after two years. With AIN 1, someone is called up again after a year to see if there is progression to AIN 2 or 3 or if the immune system has cleared the AIN 1 itself. If the pathologist detects an AIN 2 or 3, the patient is treated. The standard treatment at the moment is Electrocautery, in which the abnormalities are locally burned away.
It is generally assumed that screening for and treatment of AIN can prevent the development of anal carcinoma.
Risk groups
In the general population, the incidence of anal cancer is between 1 and 2 per 100,000 persons per year. HIV positive men who have sex with men (MSM) are the main risk group for anal cancer, with an incidence of 128-144 per 100,000 person/year. HIV negative MSM also have an increased risk. The majority of HIV positive MSM have AIN, of which more than half have AIN 2 and 3.
Anal carcinomas start from the perianal skin or the anal canal. Most anal carcinomas are squamous cell carcinomas. The abnormalities in the tissue are generally caused by the Human Papilloma Virus (HPV), a sexually transmitted virus with about 150 variants. About 15 of them are capable of causing cancer, with 16 and 18 appearing to be particularly involved in the development of anal cancer. These increase the risk of anal cancer, especially in people with an HIV infection. This is probably because the immune system is compromised, also locally in the gut.
Patients with chronic anorectal disorders (eg fistula, condylomata accuminata, proctitis) are also at increased risk.
AIN consultation hours in Jan van Goyen Medical Center
The consultation hour for screening for AIN takes place at the Dermatology outpatient clinic and is conducted by dermatologist Dr Annelinde Terlou and HIV nurse Marc van Wijk.
More information
If you want to know more about anal cancer, check out the website of www.kanker.nl
