In a randomized clinical trial with 4,446 participants, known as the Anal Cancer/HSIL Outcomes Research (ANCHOR) study, researchers found that by removing high-grade squamous intraepithelial lesions (HSIL), chances of progression to anal cancer were significantly reduced.
The trial is the first to show such findings and was performed at 21 clinical sites around the United States. Results are being prepared for peer-reviewed publication and are being shared now because of the public health importance of the findings.
The study caps decades of research into the history, prevention and treatment of anal cancer and its precursors. It also provides important information for developing standard of care guidelines for people at high risk of anal cancer, including screening for and treatment of anal HSIL, said lead investigator Joel Palefsky, MD, a professor of medicine at UCSF.
“ANCHOR data show for the first time that, like cervical cancer, anal cancer can be prevented even in high-risk populations, such as people living with HIV, who often have HSIL that can be difficult to treat,” Palefsky said. “Although the study was performed in people living with HIV, the results suggest that anal cancer prevention could be similarly possible in other groups known to be at increased risk of anal cancer, including women with a history of vulvar or cervical cancer, men who have sex with men who are HIV-negative, and men and women who have immunosuppression for reasons other than HIV infection.”
Palefsky established the world’s first clinic devoted to anal cancer prevention in 1991 at UCSF. Now known as the UCSF Anal Neoplasia Clinic Research and Education Center, it is currently based at the UCSF Medical Cancer at Mount Zion in San Francisco.
In the study, people living with HIV aged 35 years and older who had the precursor lesion were randomized into two groups: treatment of the lesion or active monitoring of the lesion without treatment.
Most often, treatment consisted of a technique performed in physician offices called hyfrecation (electrocautery), in which an electric current was targeted directly to areas of the HSIL to remove them. Participants were re-evaluated every three to six months, and rates of anal cancer were compared between the two groups.
The incidence of anal cancer is very high among people with HIV and is similar to cervical cancer: both have a strong association with human papillomavirus and are preceded by HSIL.
Cervical cancer prevention programs to find and treat cervical HSIL are the standard of care and highly effective in reducing the risk of developing cervical cancer. The investigators noted that the principal reason to consider HSIL treatment is to reduce the risk of developing anal cancer. The ANCHOR study will provide key information in guiding recommendations to make anal cancer prevention programs the standard of care for people at high risk of anal cancer.