brand logo

Am Fam Physician. 2022;106(5):585

Clinical Question

Does early treatment of screen-detected anal high-grade squamous intraepithelial lesions in patients living with HIV reduce the likelihood of progression to invasive anal cancer compared with active surveillance?

Bottom Line

Immediate treatment of screen-detected anal high-grade squamous intraepithelial lesions reduces the likelihood of progression to invasive anal cancer (number needed to treat = 111 over 26 months). The study was not powered to detect a reduction in mortality. (Level of Evidence = 1b)


People with HIV are at the highest risk of anal cancer. Although not addressed by the U.S. Preventive Services Task Force, some clinicians recommend screening for anal cancer in this group using liquid-based anal cytology (similar to screening for cervical cancer) and high-resolution anoscopy. The study invited people 35 years and older with HIV to receive anal cancer screening. The median age was 51 years, 78% were men, and 42% were Black. Groups were balanced at the start of the study, and analysis was by intention to treat. Of 10,723 people who were screened, 4,459 were given a diagnosis of anal high-grade squamous intraepithelial lesions and were randomized to receive immediate treatment or active surveillance.

Treatment was selected by the clinician and could include ablative or topical therapies (e.g., fluorouracil, imiquimod [Aldara]). All participants received high-resolution anoscopy to evaluate for recurrence (treatment group) or progression (active surveillance group). Follow-up and adherence to the assigned treatment was excellent. Anal cancer detected during the median 26-month follow-up period occurred significantly less often in the treatment group than in the active surveillance group (9 vs. 21). This corresponds to rates of progression to anal cancer of 173 per 100,000 person-years vs. 402 per 100,000 person-years and overall incidences of progression of 0.9% vs. 1.8% (number needed to treat = 111 over 26 months). More serious adverse events occurred in the immediate treatment group, including pain, infection related to biopsy, and skin ulceration, but these were rare.

Study design: Randomized controlled trial (nonblinded)

Funding source: Government

Allocation: Concealed

Setting: Outpatient (any)

Reference: Palefsky JM, Lee JY, Jay N, et al.; ANCHOR Investigators Group. Treatment of anal high-grade squamous intraepithelial lesions to prevent anal cancer. N Engl J Med. 2022;386(24):2273-2282.

Editor's Note: Dr. Ebell is deputy editor for evidence-based medicine for AFP and cofounder and editor-in-chief of Essential Evidence Plus, published by Wiley-Blackwell.

Already a member/subscriber?  Log In


From $145
  • Immediate, unlimited access to all AFP content
  • More than 130 CME credits/year
  • AAFP app access
  • Print delivery available

Issue Access

  • Immediate, unlimited access to this issue's content
  • CME credits
  • AAFP app access
  • Print delivery available
Purchase Access:  Learn More

POEMs (patient-oriented evidence that matters) are provided by Essential Evidence Plus, a point-of-care clinical decision support system published by Wiley-Blackwell. For more information, see Copyright Wiley-Blackwell. Used with permission.

For definitions of levels of evidence used in POEMs, see

To subscribe to a free podcast of these and other POEMs that appear in AFP, search in iTunes for “POEM of the Week” or go to

This series is coordinated by Natasha Pyzocha, DO, contributing editor.

A collection of POEMs published in AFP is available at

Continue Reading

More in AFP

More in Pubmed

Copyright © 2022 by the American Academy of Family Physicians.

This content is owned by the AAFP. A person viewing it online may make one printout of the material and may use that printout only for his or her personal, non-commercial reference. This material may not otherwise be downloaded, copied, printed, stored, transmitted or reproduced in any medium, whether now known or later invented, except as authorized in writing by the AAFP.  See permissions for copyright questions and/or permission requests.