Early treatment of screen-detected anal high-grade squamous intraepithelial lesions reduces progression to cancer

Reference

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

Synopsis

Persons living with human immunodeficiency virus (HIV) are at the highest risk of anal cancer. Although not yet addressed by the US Preventive Services Task Force, some clinicians recommend screening for anal cancer in this group using a liquid-based anal cytology analogous to screening for cervical cancer in women and high-resolution anoscopy. This study invited persons 35 years and older living with HIV to come in for 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 persons who were screened, 4459 were given a diagnosis of high-grade squamous intraepithelial lesions (HSIL) and were randomized to receive immediate treatment or active surveillance. Treatment was selected by the clinician and could include ablative or topical therapies (5-FU, imiquimod). 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 173/100,000 person-years versus 402/100,000 person-years, and overall incidences of progression of 0.9% versus 1.8% (number needed to treat [NNT] = 111 over 26 months). There were more serious adverse events in the immediate treatment group including pain, infection related to biopsy, and skin ulceration, but these were rare.