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Anal CancerJune 2022Summary reviewed May 2026

What the ANCHOR Trial Found — Treating Anal Pre-Cancer in People With HIV

ANCHOR enrolled 4,446 people living with HIV who had biopsy-proven anal high-grade pre-cancer lesions. After about two years, treating those lesions cut the rate of progression to anal cancer compared with watchful waiting.

What the trial was testing

The ANCHOR enrolled 4,446 patients with anal cancer. The study was sponsored by AIDS Malignancy Consortium and tracked outcomes across the full group of patients who matched the trial's eligibility profile.

It was a large trial designed to confirm whether the treatment works well enough for wider use. Trials at this stage are designed to produce evidence regulators and physicians can act on — not just observations to follow up later.

What the results showed

57% lower rate of anal cancer with treatment vs. active monitoring.

New England Journal of Medicine · 2022 · NCT02135419

These findings — that of progression to anal cancer over two years with treatment of high-grade lesions — were published in the New England Journal of Medicine and represent the headline result of the study.

Researchers tracked outcomes across 4,446 patients enrolled in the trial. The result was consistent enough across the group that the team felt confident reporting it.

What this means for patients

For patients with anal cancer, this result changes the calculus on what to ask their care team about. Whether it changes day-to-day care depends on factors like disease subtype, prior treatments, and where the patient is in their care journey.

What you can do now

The treatments tested (office-based ablation, topical fluorouracil, or imiquimod) are all available now. Major guidelines now recommend that adults living with HIV aged 35 and older get screened for anal pre-cancer with anal cytology and high-resolution anoscopy. Ask an HIV specialist or colorectal surgeon about screening.

Eligibility for the treatments mentioned above depends on specific test results and clinical history. Bring this summary, the trial name, and your most recent labs or pathology report to your next visit.