High-risk human papillomavirus test in anal smears: can it optimize the screening for anal cancer?

Objective: The current method for screening anal cancer is anal cytology, which has low sensitivity. Since high-risk human papillomavirus (HR-HPV) is associated with almost 90% of cases of anal cancer, the objective of this study is to evaluate whether testing for HR-HPV can optimize the screening.

Design: Prospective study with patients enrolled in a screening program for anal dysplasia. Considering high-resolution anoscopy (HRA)-guided biopsy as the gold standard for diagnosis of high-grade squamous intraepithelial lesions, the diagnostic performance of anal cytology, HR-HPV testing, and the combination of both was calculated.

Settings: A single center for anal dysplasia.

Participants: A total of 364 patients (72% males, 82% HIV-positive).

Intervention: Patients underwent anal cytology, HR-HPV test, and HRA-guided biopsy of the anal canal.

Main Outcome Measures: Ability of cytology and HR-HPV test (individually and combined) to detect high-grade squamous intraepithelial lesions, and analysis of the cost of each diagnostic algorithm.

Results: Cytology alone was the cheapest approach, but had the lowest sensitivity [59%, 95% confidence interval (CI) 46-71%], despite of highest specificity (73%, 95% CI 68-78%). Cotesting had the highest sensitivity (85%, 95% CI 74-93%) and lowest specificity (43%, 95% CI 38-49%), and did not seem to be cost-effective. However, HR-HPV testing can be used to triage patients with normal and atypical squamous cells of undetermined significance cytology for HRA, resulting in an algorithm with high sensitivity (80%, 95% CI 68-89%), and specificity (71%, 95% CI 65-76%), allied to a good cost-effectiveness.

Conclusion: HR-HPV testing is helpful to optimize the screening in cases of normal and atypical squamous cells of undetermined significance cytology.