What is the recommended follow-up for anal Human Papillomavirus (HPV) infection?

Follow-Up Recommendations for Anal HPV Infection

Currently, there is insufficient evidence to recommend routine anal cancer screening with anal cytology in the general population, but annual digital anorectal examination (DARE) is recommended for high-risk individuals. 1

Risk Stratification for Follow-Up

The approach to anal HPV follow-up should be based on risk factors:

High-Risk Groups Requiring Regular Screening:

• Men who have sex with men (MSM) with HIV infection: Begin screening at age 35 with highest risk (80-131 cases per 100,000 person-years) 1, 2
• Men with HIV infection: Begin screening at age 45 (40-60 cases per 100,000 person-years) 1, 2
• Women with HIV infection: Begin screening at age 45 (20-30 cases per 100,000 person-years) 1, 2
• MSM without HIV infection: Begin screening at age 45 (14 cases per 100,000 person-years) 1, 2
• Solid organ transplant recipients: Begin screening 10 years post-transplant 2
• Women with history of vulvar precancer or cancer: Begin screening within 1 year of diagnosis 2

Moderate Risk Groups (Consider Screening with Shared Decision-Making):

• Persons aged ≥45 years with history of cervical/vaginal HSIL or cancer 2
• History of perianal warts 2
• Persistent (>1 year) cervical HPV16 2
• Autoimmune conditions 2

Recommended Screening Methods

Digital Anorectal Examination (DARE):

• Recommended annually for high-risk individuals, particularly persons with HIV infection and MSM without HIV with a history of receptive anal intercourse 1
• Acceptable to patients with low risk for adverse outcomes 1
• Purpose: To detect masses on palpation that could indicate early anal cancer 1

Anal Cytology:

• Not routinely recommended for general population due to insufficient evidence 1
• May be considered in specialized clinical centers for high-risk populations 1
• Sensitivity limitations: 55-89% sensitivity and 40-67% specificity for detecting HSIL 1, 3
• Important caveat: Should only be implemented if referrals to high-resolution anoscopy (HRA) and biopsy are available 1

HPV DNA Testing:

• May be used in combination with cytology (co-testing) to improve sensitivity 3
• Higher sensitivity (96-100%) but lower specificity (16-36%) compared to cytology alone 3
• Algorithm options:
  • Algorithm A: Benign cytology/HPV16/18 positive or ASCUS/hrHPV positive 3
  • Algorithm B: Benign or ASCUS/hrHPV positive (highest sensitivity at 97-100%) 3

Follow-Up Protocol for Abnormal Results

For Abnormal Anal Cytology:

• Referral to high-resolution anoscopy (HRA) for abnormal cytologic results (e.g., ASC-US, LSIL, or HSIL) 1
• HRA with biopsy for definitive diagnosis of high-grade squamous intraepithelial lesions (HSIL) 1
• Monitoring response to therapy and surveillance for evidence of progression using HRA 1

For High-Risk Individuals Without Abnormal Results:

• Annual DARE is recommended for ongoing surveillance 1
• Consider co-testing with anal cytology and HPV DNA testing in specialized centers with access to HRA 3, 2

Special Considerations

Women with Concurrent Cervical HPV:

• Higher risk of anal HPV: Women with cervical HR-HPV have 4 times higher odds of anal HR-HPV infection 4
• Consider anal screening: Particularly for women with persistent cervical HPV16 or history of cervical/vulvar dysplasia 4, 2
• Clearance rates: While anal oncogenic HPV genotypes have higher clearance than acquisition rates (51.2% vs 14.8%), the prevalence and incidence of anal HSIL remain high 5

HPV Vaccination:

• Recommended for prevention: HPV vaccination is recommended for all females aged 9-26 years and all males aged 9-21 years 1
• Males aged 22-26 years should also be vaccinated if not vaccinated at younger ages 1
• Efficacy: HPV vaccines demonstrate high efficacy against anal infections and anal intraepithelial neoplasia 6
• Important note: Even with vaccination, screening as per guidelines is still recommended 6

Common Pitfalls to Avoid

• Don't assume low risk despite negative initial screening; follow-up is still important for high-risk individuals 1
• Don't implement cytology screening without access to HRA and biopsy services 1
• Don't delay evaluation of abnormal screening results in high-risk individuals 1
• Don't rely on a single screening method alone; consider combination approaches for higher sensitivity 3