Validation of HPV triage in cytology-based cervical cancer screening for ASC-US cases using Japanese data.

OBJECTIVE: In Japan, cervical cancer screening consists of a cytology examination performed once every 2 years. We verified whether the risk of cervical intraepithelial neoplasia (CIN) 3 disease or higher (CIN3+) was equivalent to that of cytology negative cases (negative for intraepithelial lesion or malignancy [NILM]) for patients with a cytological diagnosis of "atypical squamous cells of undetermined significance (ASC-US)" who tested negative for human papillomavirus (HPV). METHODS: Data from a total of 22,925 cases who had undergone cervical cancer screening at least twice or who had completed follow-up examinations after cervical screening at a single facility between April 2013 and April 2018 were analyzed. The cumulative incidence of CIN3+ was calculated for each category of initial cytology finding and HPV result (NILM, > ASC-US, ASC-US/HPV (unknown), ASC-US/HPV+, and ASC-US/HPV-). The statistical analysis was conducted using the Cox proportional hazards model. RESULTS: The hazard ratio for the cumulative incidence of CIN3+ in 2 years relative to that for NILM cases was 2.7 (95% confidence interval=1.0-7.8) for > ASC-US cases, 0.5 (0.1-1.7) for ASC-US/HPV (unknown), 0.8 (0.3-2.4) for ASC-US/HPV+ cases, and 0.3 (0.1-1.0) for ASC-US/HPV- cases. CONCLUSION: Because the cumulative incidence of CIN3+ at 2 years for the ASC-US/HPV- cases was sufficiently low, compared with that of the NILM cases, we considered it reasonable and safe to perform HPV triage for ASC-US cases and to allow HPV-negative cases to return for their next screening in 2 years, which is the same follow-up schedule as that for NILM cases.

The first-round results of a population-based cohort study of HPV testing in Japanese cervical cancer screening: baseline characteristics, screening results, and referral rate.

OBJECTIVE: In 2013, a cohort study aimed to clarify the positive and negative effects of introducing the human papillomavirus (HPV) testing for population-based cervical cancer screening has been launched in Japan. This study included four screenings during the subsequent 7-year follow-up period. We aim to describe the results of the first round of this study on cervical cancer screening here. METHODS: This study began in September 2013 with recruitment completed in March 2016. Women aged 30-49 years were divided into 2 groups: those who received uterine cervical cytology alone in the first year (control group), or those who received a combination of cytology and HPV testing (intervention group), based on their age. After first screening, women with positive result of cytology or positive HPV test required referral. We summarized the results of the first round of cervical cancer screening. RESULTS: Of the 25,074 women who were eligible for the study, 13,845 women (55.2%) were screened with cytology alone; 11,229 women (44.8%) received a combination of cytology and HPV testing. After screening, 407 women (2.9%) in the control group and 1,003 women (8.9%) in the intervention group required referral, respectively. Adding HPV testing increased referral rate significantly (p<0.001). CONCLUSION: After first screening, introduction of HPV testing appears to contribute to significantly higher referral rates, suggesting that the number of colposcopies as a detailed examination may increase. These preliminary findings suggest that if HPV testing is introduced into screening, medical institutions need to be prepared for an increasing number of follow-up examinations.

National screening programs for cervical cancer in Asian countries.

Cervical cancer is still one of the most common female cancers in Asia and the leading cause of cancer-related deaths in low- and middle-income countries. Nowadays, national screening programs for cervical cancer are widely provided in Asian countries. We reviewed the National Cancer Screening Program (NCSP) in China, India, Indonesia, Japan, Korea, and Thailand. The NCSP were established at varying times, from 1962 in Japan to 2014 in Indonesia. The primary screening method is based on cytology in all countries except for India and Indonesia. In India and Indonesia, visual inspection of the cervix with acetic acid (VIA) is mainly used as a primary screening method, and a "see and treat" strategy is applied to women with a positive VIA result. The starting age of NCSP ranges from 18 years in China to 30 years in Thailand. The screening interval is 2 years in all countries except for China and Indonesia, in which it is 3 years. Uptake rates of NCSP vary from 5.0%-59.7%. Many women in low- and middle-income countries still do not participate in NCSP. To improve uptake rates and thereby prevent more cases of cervical cancer, Asian countries should continue to promote NCSP to the public using various approaches.