Anal high-grade squamous intraepithelial lesions, also known as aHSIL, is caused by chronic infection with the human papillomavirus (HPV). While high-grade squamous intraepithelial lesionsabnormality (HSIL), when untreated, is generally associated with cervical cancer, anal HSIL and cervical HSIL share cytopathologic features, and are both described using the Bethesda classification system.
According to recent data, from a multi-site study supported by the National Cancer Institute at the National Institutes of Health, demonstrates that the disease, which precedes anal cancer, is increasing in both incidence and prevalence. The same data shows that prevalence of HSIL is much higher in women living with HIV than previously reported.
A new strategy needed
The results of the study, conducted by researchers from the AIDS Malignancy Consortium, call for new strategies to be developed for wider screening of women living with HIV, who have disproportionally higher rates of anal cancer compared to the general population of women. The study appears in Clinical Infectious Diseases.
To determine the true prevalence of anal HSIL in women living with HIV in the United States, the researchers, for the first time, conducted a full anal evaluation including a high-resolution anoscopy, an examination of the anus under magnification, with directed biopsy on all 256 female study participants.
The participating women did not only include those who had an abnormal screening test or triage. The prevalence of anal HSIL was 27%, substantially higher than previous study estimates, which ranged between 4 – 9%.
“We believe most prior studies of anal HSIL prevalence in women living with HIV underrepresented the true percentage because only individuals with abnormal anal cytology underwent high-resolution anoscopy in past studies, compared to all the participants in this new study,” noted Elizabeth Chiao, MD, MPH, the co-author and principal investigator of the study.
Chiao is a professor of medicine in the section of infectious diseases at Baylor College of Medicine and with the Houston VA Center for Innovations in Quality, Effectiveness and Safety.
The study was conducted at 12 academic medical centers across the United States, with the participants recruited between 2014 and 2016. The mean age of participants was 49.4 years, 64% were non-Hispanic black, and 67% were former or current smokers, and 56% reported ever having anal sex with a man.
The median CD4 T-cell count was 664 cells/μL. The prevalence of anal histologic HSIL (hHSIL) was 27% (95% confidence interval [CI], 22%–33%). There was a strong concordance (240/254) between local and consensus pathologists for hHSIL vs. less than hHSIL (κ = 0.86 [95% CI, .79–.93]).
The researchers found that a CD4 count of ≤200 cells/μL was the strongest predictor of consensus anal hHSIL diagnosis (adjusted odds ratio [aOR], 10.34 [95% CI, 3.47–30.87]). History of anoreceptive intercourse was also associated with hHSIL (aOR, 2.44 [95% CI, 1.22–4.76]).
“The high prevalence of anal cancer precursors and invasive anal cancer among women living with HIV calls for greater screening in this population,” said lead author Elizabeth A. Stier of Boston Medical Center, who also is an associate professor of obstetrics and gynecology at Boston University School of Medicine.
“Because optimal screening strategies are still not yet known, prevention of anal cancer among this population should focus on identifying cost-effective strategies for the detection and management of anal cancer precursors,” Stier added.
Screening women living with HIV for anal cancer has been recommended by national organizations, including the American Cancer Society, the Infectious Diseases Society of America and the American Society of Colon and Rectal Surgeons.
 Pineda CE, Welton ML. Management of anal squamous intraepithelial lesions. Clin Colon Rectal Surg. 2009;22(2):94–101. doi:10.1055/s-0029-1223840
 Stier EA, Lensing SY, Darragh TM, Deshmukh AA, Einstein MH, Palefsky JM, Jay N, et al. Prevalence of and Risk Factors for Anal High-grade Squamous Intraepithelial Lesions in Women Living with Human Immunodeficiency Virus. Clin Infect Dis. 2019 Jul 11. pii: ciz408. doi: 10.1093/cid/ciz408. [Epub ahead of print][Article]