Prevalence of non 16/18 high risk human papilloma virus as a quality metric in gynecological cytology

Abstract

AbstractHuman papillomavirus (HPV) is the most common sexually transmitted pathogen that causes anogenital disease. Cervical screening by cytology and HPV testing (co‐testing) are important in prevention of cervical cancer. The Bethesda System category of atypical squamous cells (ASC) is used when a neoplastic process cannot be confidently identified. In such cases, the differential diagnosis is broad and includes benign conditions. Monitoring of ASC/SIL ratio is a commonly used laboratory quality assurance measure to prevent over‐ or under‐use of this category. High risk human papillomavirus (hr‐HPV) has been used in conjunction with the ASC/SIL ratio in determining whether a particular pathologist is over/under‐using the indefinite category. However, the laboratory overall sample population prevalence rate of hr‐HPV subtypes has not been previously examined for association with the ASC rate. In this study, the relationships between ASC/SIL ratio and hr‐HPV prevalence rate and hr‐HPV subtypes (16/18 and non‐16/18) to the laboratory ASC prevalence were studied. The results demonstrate that HPV non‐16/18 is the main subtype which is associated with ASC‐US category. A large proportion of non‐16/18 HPV‐related cases are seen in young patients, which largely abates by the by fourth decade. In addition, there are differences in the ASC/SIL ratio for HPV 16/18 and non‐16/18 types. The overall ASC/SIL ratio is an average of the ASC/SIL rate for the non‐16/18 population and the HPV 16/18 population. Instead of basing the laboratory and practitioners' quality indicator solely on ASC/SIL ratio, the overall prevalence of HPV and its subtype ratio should also be reported as they are more reflective of laboratory performance.