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)

Synopsis

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.