Population-based cohort study assessing the efficacy of cervical cytology (Pap smear) and human papillomavirus (HPV) testing as modalities for cervical cancer screening.

In cervical cancer screening, several trials have shown that human papillomavirus (HPV) testing or combined HPV testing and cytology leads to earlier detection of cervical intraepithelial neoplasia Grade 3 or worse (CIN3+) compared with cytology alone. However, the availability of similar evidence in our country remains limited. In 2013, 34 local governments were selected to administer a cervical cancer screening program utilizing either cytology alone or in combination with HPV testing. We planned a cohort study to assess the effectiveness of HPV testing as a modality for cervical cancer screening. The primary outcome of this study was the incidence of CIN3+ in each group, as well as to assess the risks and benefits of receiving screening for women in both groups. These results will contribute to elucidating the details of the positive and negative impacts of introducing HPV testing into a population-based cervical cancer screening program in Japan.