The Impact of Triage for Atypical Squamous Cells of Undetermined Significance with Human Papillomavirus Testing in Cervical Cancer Screening in Japan

Abstract

Background: One of the features of cervical cancer screening using the combination of cytology and human<br />papillomavirus (HPV) testing is the triage for atypical squamous cells of undetermined significance (ASC-US). The<br />effectiveness of the triage has been recognized widely. However, there are few reports evaluating this triage process in<br />Japan. Material and Methods: We retrospectively examined the results of cytology and HPV co-testing for cervical<br />cancer screening in the Oyama area of Tochigi Prefecture between 2012 and 2014. Women who were ASC-US/HPV<br />positive and had cytologic abnormalities [low-grade squamous intraepithelial lesions (LSIL) or worse] were examined<br />by colposcopy. The results of the colposcopy testing were evaluated. In addition, we also examined the results of those<br />who underwent co-testing a year after a ASC-US/HPV-negative result. Results: A total of 21,342 women received<br />their first screening test during the study period, with 542 (2.5%) found to have ASC-US. Of the ASC-US-positive<br />women, 289 (53.3%) were also HPV positive. The prevalence of CIN+ (cervical intraepithelial neoplasia or higher)<br />in the ASC-US/HPV-positive group was 63.2%, with 81.8%, 16.4% and 4.8%. showing CIN 1, CIN 2 and CIN 3+,<br />respectively. The prevalence of CIN+ in the LSIL group was 66.8%, with the majority having a low risk CIN 1 (76.6%)<br />compared to CIN 2 (18.6%), and CIN 3+ (4.8%). No significant difference was observed between the LSIL and ASC-US/<br />HPV-positive groups. The prevalence of women diagnosed with CIN in the ASC-US/HPV-negative group, following<br />co-testing a year after colposcopy was low (3%). Conclusions: The ASC-US/HPV-positive group was comparable to<br />the LSIL group in terms of prevalence of CIN+ lesions. Furthermore, low CIN prevalence after one year in the ASCUS/<br />HPV-negative group provides confirmation that the screening interval could be extended. The application of HPV<br />triage (which is routine in other countries) to identify these groups would be of benefit in Japan.