People Living With HIV at Increased Risk for Anal Cancer: NCI Study

Anal cancer incidence rates have been increasing for years in the United States and people living with HIV are at an increased risk of developing anal cancer.

A recently published study titled “Impact of HIV on Anal Squamous Cell Carcinoma Rates in the United States, 2001-2015” that was published in the Journal of the National Cancer Institute examined the trend, and the researchers shared some ideas about what might be done about it.

Meredith Shiels

“In prior analyses, we showed that during 1980-2005 in the U.S., 28% of anal cancers among men and 1% of anal cancers among women occurred among people with HIV,” said study author Meredith Shiels, Ph.D., M.H.S., a senior investigator in the Division of Cancer Epidemiology and Genetics of the National Cancer Institute. “We sought to extend this analysis to 2001-2015 and estimate the fraction of the general population anal squamous cell carcinomas, the major histologic subtype of anal cancer, that occurred among people living with HIV in the U.S.”

The researchers also sought to understand how anal squamous cell carcinomas (SCCs) among people with HIV have influenced trends over time in anal SCC incidence rates.

Data was obtained from a linkage of HIV and cancer registries in a dozen U.S. regions. The

proportion of anal SCCs occurring among people living with HIV was estimated by sex, age group and race and ethnicity.

The National Cancer Institute’s HIV/AIDS Cancer Match Study is the world’s largest study of cancer among people living with HIV and 44 % of individuals living with HIV in the U.S. reside in the regions included in the study, Shiels said. “This study is ideal because it includes a large number of people living with HIV and also includes general population cancer registry data for comparison.”

The findings showed that during 2001-2015, for men, 32.5% of anal SCCs occurred in people with HIV, while for women, 3% occurred in people with HIV. The fraction of anal SCCs among people with HIV was greatest in the 20-49 age group and in Black and Hispanic individuals. Shiels noted the disproportionate burden of HIV among Black and Hispanic individuals in the U.S. and that it is likely attributable to socio-ecological factors that influence HIV prevention and treatment outcomes.

“Among men, but not women, increases in rates of anal SCC between 2001-2009, followed by a nonsignificant downward trend, were strongly influenced by anal SCCs among people with HIV,” Shiels said. “Public health measures aimed at preventing anal SCCs among people living with HIV could substantially reduce anal SCCs in the U.S. population.”

Though anal cancer is rare in the general population, it is a leading cancer site among people with HIV. Therefore, the research team stressed that more research focused on the prevention, early detection and treatment of anal cancer is needed in this population.

“It is important to note that human papilloma virus (HPV) vaccination protects against anal cancer, and more research is needed to understand the effectiveness of HPV vaccination among people living with HIV,” Shiels said.