Imiquimod for Anal High Grade Intraepithelial Neoplasia: A Systematic Review

Area of Science:

• Oncology
• Dermatology
• Virology

Background:

• Anal High Grade Squamous Intraepithelial Lesion (HSIL) is a condition requiring effective treatment.
• Imiquimod is a topical immune response modifier with potential therapeutic applications.

Purpose of the Study:

• To systematically review the efficacy of imiquimod for treating anal HSIL.
• To evaluate treatment response rates and safety profiles of imiquimod in anal HSIL patients.

Main Methods:

• A systematic literature search was conducted across major electronic databases.
• Studies reporting imiquimod use for anal HSIL were included up to December 2024.
• Data from 5 studies (2 RCTs, 3 prospective non-randomized) involving 126 HIV-positive men were analyzed.

Main Results:

• Complete response (CR) rates for imiquimod treatment ranged from 14.3% to 78.6%, with partial response (PR) rates between 21.4% and 67%.
• Perianal HSIL demonstrated significantly higher CR rates (71.4%–100%) compared to intra-anal HSIL (10.8%–33.3%).
• A second course of imiquimod yielded incremental response rates.

Conclusions:

• Imiquimod is a safe treatment option for anal HSIL, especially for perianal lesions.
• High recurrence rates and lack of long-term efficacy data necessitate further investigation.
• Current data do not include women or HIV-negative patients.