ThinPrep Pap-smear and cervical intraepithelial neoplasia in reproductive-aged Thai women.

Objective: To estimate the incidence of abnormal cervical cytology by ThinPrep Pap-tests and cervical intraepithelial neoplasia (CIN) in young adult reproductive-aged Thai women.

Method: A total of 1254 women distributed in all regions of Thailand were monitored from 2002 through 2004. Women were screened for abnormal cervical cytology using the ThinPrep method every 6 months. Interpretation of cervical cytology was based on the Bethesda system, version 2001. Women who had the ThinPrep Pap results as atypical squamous cells of undetermined significance or worse underwent colposcopic examination. The ThinPrep and all cervical tissue samples obtained from diagnostic or therapeutic procedures were analyzed and reviewed by Covance Central Laboratory Service, Inc., Indianapolis, USA.

Result: The cumulative incidence of abnormal ThinPrep Pap-tests was as follows: 15.3 per 100 woman years (WY) (95% confidence interval [CI] 12.3, 18.9) at 6 months; 12.3 per 100 WY (95% CI 10.3, 14.6) at 12 months; and 11.6 per 100 WY (95% CI 10.0, 13.5) at 18 months. Of 1448.6 woman years of follow up, the incidence of CIN1 was 4.1 per 100 WY (95% CI 3.2, 5.3); CIN2 0.8 per 100 WY (95% CI 0.4, 1.4); and CIN3 0.6 per 100 WY (95% CI 0.3, 1.2).

Conclusion: The incidence of abnormal ThinPrep Pap-test and CIN in young adult Thai women had been reported. No comparable data is available.