Background: The prevalence of high-grade cervical intraepithelial neoplasia (CIN2+), especially invasive cancer, among Thai women with high-grade squamous intraepithelial lesion (HSIL) cytology was reported higher than in Western populations. The aim of this study was to evaluate the prevalence of underlying significant cervical lesions (CIN2+) in women with HSIL cytology.
Materials and Methods: A total of 4,487 women from the Woman Health Centre of Chulabhorn Hospital, Bangkok and 1,523 women from Bangkhayaeng District of Pathumthani province, Thailand, who participated in a cervical cancer screening program between July 2011 and August 2013, were recruited into the study. A total of 22 women (14 from Chulabhorn Hospital and 8 from Bangkhayaeng District) with HSIL cytology were recruited for colposcopic evaluations.
Results: Of the 22 women with HSIL cytology, the median age was 42 years (22 to 67 years). The majority of patients were multiparous (90.9%) and premenopausal (72.7%). Final pathological results were as follows: 20 (91.0%) with CIN 2, CIN3 or adenocarcinoma in situ; 0 (0%) with CIN 1; 1 (4.5%) with no epithelial lesion; and 1 (4.5%) with cervical cancer. No clinical factors were associated with CIN2+.
Conclusion: Rates of CIN 2+ at initial colposcopy following HSIL cytology in our population were very high (95.5%) and support the “see-and-treat” strategy for HSIL cytology management.

Keywords: Prevalence, Cervical intraepithelial neoplasia (CIN), High-grade squamous intraepithelial lesion (HSIL), See and treat, Thailand