Why should I screen patients for anal cancer?

Detection and removal of precancerous lesions (HSIL) can prevent progression to anal cancer. In people at higher risk for anal cancer, the benefits of anal cancer screening (ACS) likely outweigh the risks. ACS is NOT recommended in the general population because anal cancer incidence is very low; however, in groups at higher risk for anal cancer, ACS is recommended, usually with an age threshold for initiation.

Whom should I screen for anal cancer?

Target screening groups include people with HIV (PWH), solid organ transplant recipients who have received at least 10 years of immune suppression (SOTR), people with history of vulvar HSIL or vulvar cancer, men who have sex with men (MSM), and transgender women (TGW).

What age should the screening start?

We recommend screening start at age 35 for MSM and TGW with HIV, at age 45 for other men and women with HIV, and HIV-negative MSM and TGW. SOTRs should start screening 10 years post-transplant. Those with history of vulvar HSIL or cancer should start screening within 1 year of the diagnosis. This is not an exhaustive list of when screening should commence.  Please refer to the guidelines linked below for the full recommendations from the IANS guidelines (International Anal Neoplasia Society's consensus guidelines for anal cancer screening - Stier - 2024 - International Journal of Cancer - Wiley Online Library); there may be other national or local guidelines to consider.

How do I screen for anal cancer?

The initial ACS screen is to determine that your patient is in a high-risk group and is of the appropriate age to offer screening test(s). Next, patients can be further risk stratified by using anal cytology (“Pap”), high-risk HPV testing, or both. We recommend that digital anorectal exam be performed at the time of screening test specimen collection. Screened patients who meet referral criteria based on cytology and/or HPV results should be referred for high-resolution anoscopy (HRA). You can check with your HRA referral resource for their referral threshold. If HRA is not available, we do not recommend screening with cytology and high-risk HPV, rather we recommend digital anal rectal examination (DARE) alone. Abnormal findings on DARE should be referred to a colorectal surgeon, or if not available, to a general surgeon for further evaluation.

Which providers should be performing ACS?

Screening collection for cytology and high-risk HPV can be performed by any clinician. In some areas, swab collection may be performed by an RN (Registered Nurse) if that is within their scope of practice. HRA can be performed by clinicians (advanced practice providers or physicians) with specific training and certification.  These clinicians may practice in many specialties, including primary care, infectious disease, gastroenterology, surgery, or gynecology.

Should ACS be offered to any individual who engages in anoreceptive sex?

No. Screening should focus on high-risk groups. Anoreceptive sex alone, is not considered an independent risk factor for anal cancer at this time.

What is the interval for screening?

The optimum ACS interval has not been determined. Screening intervals may vary based on findings and local protocols. For people with persistently negative screening results, screening every 1-2 years is reasonable.

Can I screen for anal cancer with colonoscopy?

No. Colonoscopy does not adequately evaluate the anal canal. Anal cytology (Pap test) and high-resolution anoscopy (HRA) are the preferred screening tools.

Is anal HSIL a type of anal cancer?

No. Anal high-grade squamous intraepithelial lesion (HSIL) is a precancerous condition, not cancer. However, it has the potential to develop into cancer if untreated.  The lifetime risk of developing anal cancer with untreated HSIL is estimated to be ten percent.

How do I get reimbursed for anal cancer screening?

Reimbursement depends on your country’s healthcare system. In many places, reimbursement may be available for high-risk individuals under preventive care codes. Check with local health authorities or insurance providers.

Where can I learn to perform HRA?

If you have interest in becoming an HRA provider you can find information on the IANS website.

What steps are involved in setting up an HRA service?

Setting up an HRA service involves training clinicians, investing in the right equipment, and creating clear protocols for screening, biopsies, and follow-up. The service works closely with pathology and colorectal services to coordinate testing and care. “2016 IANS International Guidelines for Practice Standards in the Detection of Anal Cancer Precursors” — gives foundational standards for HRA services (J Low Genit Tract Dis. 2016 Oct;20(4):283-91. doi: 10.1097).