# ANCHOR: treating anal high-grade squamous intraepithelial lesions to prevent anal cancer in people living with HIV

Source: https://onco.cc/key-papers/paper-anchor-anal-hsil-treatment-nejm-2022/  
OnCo record `paper-anchor-anal-hsil-treatment-nejm-2022` (Key paper). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Treating anal precancer, mostly by burning it off in the clinic, cut the number of people with HIV who went on to develop anal cancer by more than half compared with watching and waiting. It is the first randomised proof that treating an HPV precancer outside the cervix prevents cancer.

## Summary

Randomised trial of 4,459 people living with HIV aged 35 or older with biopsy-proven anal high-grade squamous intraepithelial lesions (HSIL), assigned to treatment (office-based electrocautery or infrared coagulation, topical fluorouracil or imiquimod, or excision) or to active monitoring with high-resolution anoscopy every six months.

The trial was stopped early for efficacy: 9 participants in the treatment arm and 21 in the monitoring arm progressed to anal cancer, a rate of 173 against 402 per 100,000 person-years, a 57 percent reduction. The result made screening and treatment of anal HSIL a recommendation for people living with HIV.

## Fields

- Kind: Key paper
- Last checked: 2026-09-18
- Journal: New England Journal of Medicine
- Year: 2022
- DOI: 10.1056/NEJMoa2201048
- Authors: Palefsky JM, Lee JY, Jay N, et al.
- Findings: Progression to anal cancer in 9 treated versus 21 monitored participants; 173 versus 402 cases per 100,000 person-years.; A 57 percent reduction in the rate of anal cancer, meeting the stopping boundary at a planned interim analysis.
- What it means: People living with HIV who have anal HSIL should be offered treatment rather than observation, and screening programmes to find those lesions are now justified. High-resolution anoscopy capacity is the limiting step.
- Caveats: Only people living with HIV were enrolled; the benefit in other high-risk groups is inferred.; Recurrence of HSIL after treatment was common, so surveillance continues after treatment.

## Sources

- N Engl J Med 2022: https://doi.org/10.1056/NEJMoa2201048
- PubMed: https://pubmed.ncbi.nlm.nih.gov/35704479/

## Connected records

- cancers: [Anal high-grade squamous intraepithelial lesions (precursor)](https://onco.cc/cancers/anal-hsil-precursor/)
- drugs: [Fluorouracil (5-FU)](https://onco.cc/drugs/fluorouracil/)
- journals: [New England Journal of Medicine](https://onco.cc/journals/nejm/)

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