Implementation of primary HPV testing in Japan.

Cervical cancer screening has been shifting from primary cytology to primary HPV testing worldwide as primary HPV testing is more sensitive than primary cytology. To the best of our knowledge, the current study is the first in Japan to examine the feasibility of primary HPV testing. One of the disadvantages of this shift is that hrHPV-/≥LSIL/CIN2+ (high-risk HPV negative cancers or pre-cancerous lesions with abnormal cytology results) can be missed. The objectives of the present study are to clarify in detail CIN2+ missed by this shift and to evaluate the feasibility of primary HPV testing in Japan. Data from 115,273 women who underwent co-testing with cytology and HPV testing in cancer screening were used in the current study. The cases with hrHPV-/≥LSIL ('hrHPV-/≥L-SIL' include CIN2-, in contrast, 'hrHPV-/≥L-SIL/CIN2+' doesn't include CIN2-) were analysed in detail. Women with hrHPV-/≥LSIL comprised 0.3% of the total. The prevalence of CIN2, CIN3, SCC or cervical adenocarcinomas in the lesions with HPV-/≥LSIL was 0.03% in the cancer screening group. Only one case of 14 cervical adenocarcinomas in ≥LSIL was hrHPV-. The prevalence of cancer missed by the shift in patients >50 years of age was significantly higher compared with patients younger than 49 years. In conclusion, the prevalence of CIN2+, which might be missed by the shift from primary cytology to primary HPV testing, was remarkably low in this Japanese cancer screening. The data indicated that primary HPV testing, which was more sensitive for CIN2+ than primary cytology, was a feasible method that can be used in Japan. In particular, primary HPV testing should be introduced for women <50 years old.