The use of conization to identify and treat severe lesions among prediagnosed CIN1 and 2 patients in Japan

OBJECTIVE: To evaluate the clinical efficiency of identifying patients with suspicious severe lesions by conization among prediagnosed cervical intraepithelial neoplasia (CIN) 1 and 2 patients in Japan. METHODS: The data in a Japanese nation-wide registry for cervical cancer (2009 and 2011) was collected to analyze the clinical efficacy of pre- and postdiagnosis for 13,215 Japanese women who underwent treatment by conization. Their preoperative and postoperative histologic findings and clinical outcomes were evaluated using standard statistical procedures including clinical and demographic characteristics. RESULTS: Almost half of 1,536 women who were treated by conization after the prediagnosis of CIN1 and 2 because the lesions showed no evidence of natural regression actually contained CIN1–2 (45.0%), CIN3 (47%), or invasive cancer (2.7%) in their cervical tissue. They underwent conization either for therapeutic (treatment) (78.5%) or diagnostic (21.5%) reasons. Invasive disease was diagnosed postoperatively more often in diagnostic cases (6.1%) than in therapeutic cases (2.8%). All the patients survived their diagnostic and therapeutic conization after approximately 30 months of follow up. CONCLUSION: Our study shows that the continuous observation of the prediagnosed CIN1 and 2 cases by the combination of cytology, colposcopy and histology in Japan has worked successfully to identify severe lesions by using conization as well in the process.