In June, a study supported by the National Cancer Institute found that for people with HIV, early treatment of precancerous anal lesions caused by human papillomavirus (HPV) can cut rates of anal cancer incidence by more than half. These findings from the Anal Cancer/HSIL Outcomes Research (ANCHOR) study are creating secondary prevention options for those at risk for anal cancer who have not received the HPV vaccine. We look into the history of the study and what its work means for those at risk for anal cancer.