Comparative evaluation of efficacy and safety of high-resolution anoscopy (HRA)-guided topical treatment (trichloroacetic acid, TCA) vs. surgical treatment (electrocautery, ECA) in HIV-positive patients for human papillomavirus (HPV)- induced AIN, an anal cancer precursor. The primary hypothesis is that cost-saving and simple TCA treatment is non-inferior to the current best option therapy with ECA. TCA treatment would also be possible in the normal setting of a doctor´s office without extensive specialization and without complex technical equipment.

Anal human papillomavirus (HPV)-infection and HPV-induced AIN, an anal cancer precursor, are very frequent in HIV-positive patients (HIV+), especially in men who have sex with men (MSM), but also in women. Consequently, HIV+ have a strongly increased risk for anal cancer. Screening for and treatment of AIN are recommended in HIV+, although only two RCT on AIN treatment have been published. We plan a multicenter, unblinded, non-inferiority RCT that evaluates the efficacy and safety of 2 high-resolution anoscopy (HRA)-guided treatment options for AIN: topical application of trichloroacetic acid (TCA) and surgical treatment with electrocautery (ECA).

ECA was the best option for intra-anal AIN in a recent randomized controlled trial (RCT). TCA, an inexpensive and established therapy for genital warts, has been evaluated for AIN only in a retrospective pilot study that showed clearance rates comparable to those found for ECA, with possibly less adverse events (AE). Our primary hypothesis is that cost-saving and simple TCA is non-inferior to ECA. 2800 HIV+ will be screened by HRA in 9 proctological centers and 560 HIV+ with histologically confirmed intra-anal AIN will be randomized (1:1) to receive up to 4 treatments with TCA or ECA within 12 weeks. The primary efficacy endpoint is clinical (HRA) and histological resolution of AIN 4 weeks after the last treatment. Secondary endpoints comprise recurrence of AIN 24 weeks after end of therapy, the number of interventions, AE, and the influence of HPV parameters such as anal HPV-types, viral load and HPV-oncogene-mRNA.

Inclusion Criteria:

• HIV positive patients
• Legally eligible patients and age ≥ 18 years
• Sufficient knowledge of the German language, spoken and written
• Patient is willing and able to appear regularly to the treatment- and follow-up appointments
• Clinically visible AIN-lesion, which was confirmed by histopathology (findings not older than 2 weeks after the date of collection and removal date no longer than 16 weeks prior to baseline)
• Written informed consent

Exclusion Criteria:

• Currently diagnosed anal cancer or anal cancer in anamnesis (within the last 5 years)
• Acute life-threatening disease
• Participation in a proctologic study within the last 30 days
• Participation in this study at an earlier date
• Simultaneous participation in another clinical trial, which excludes the participation in this study
• Simultaneous topical and systemic treatments wtih medications that affect the study outcome, such as immunomodulatory substances: Interferone, imiquimod or systemic glucocorticosteroids
• lactation
• Pregnancy: In patients of childbearing age, a pregnancy has to be ruled out by pregnancy test or other suitable methods.
• Women of childbearing potential without adequate contraceptive protection.
• Contraindication for using trichloroacetic acid or electrocautery
• Patients in whom general anesthesia in the treatment of AIN is necessary already at study start
• Other serious intra-anal and proctologic disorders, which make additional proctologic or systemic treatments necessary, which influence the study result, such as an active Crohn's disease, which must be treated locally and systemically with immunosuppressives or an active proctitis.
• Patients who have been vaccinated before baseline against HPV