The incidence of anal cancer has increased significantly over the past three decades, particularly among HIV-infected individuals, with an estimated rate of 90 per 100,000 person-years. HSILs are known to precede the development of anal cancer, and research has shown that treating HSILs can reduce the risk of cervical cancer. However, there has been a lack of evidence to support the use of treatment to prevent anal cancer.
To address this, a phase 3 North American multicenter trial was conducted between 2014 and 2021. The trial included 4,151 HIV-infected patients aged 35 or older with HSILs of the anus, who were randomized to either receive HSIL treatment or active surveillance without treatment. Treatment consisted of thermodestruction or excision under anesthesia, and/or local administration of fluorouracil or imiquimod. All patients had a high-resolution anoscopy at least every 6 months and biopsies in case of HSIL and/or suspected cancer. The primary endpoint was progression to anal cancer.
The results of the study showed that after a median follow-up of 25.8 months, the rate of progression to anal cancer was 57% lower in the treatment group compared to the active surveillance group. Side effects from the treatments were rare. This study has conclusively demonstrated that treating HSILs can reduce the risk of anal cancer.
Given this evidence, it is recommended that individuals with HSILs of the anus receive treatment in order to reduce the risk of developing anal cancer. Furthermore, further research should be done to explore the efficacy of treatment options for HSILs of the anus, as well as the potential benefits of early detection and prevention of anal cancer.
