Prevalence of High Grade Lesions in LSIL Pap Cases

Cervical cancer is the second most common cancer among women worldwide, with the estimated 493,000 new cases and 274,000 deaths in 2002 (Parkin et al., 2005). The incidence is much higher in developing countries. In Thailand, cervical cancer is the most common gynecologic cancer with the age-standardized incidence rate (ASR) of 19.5 per 100,000 per year (Pengsa and Jindawijak, 2003). Cervical cancer screening program is an important means for early cancer detection. Conventional cytologic Papanicolaou’s smear (Pap smear) has been the most widely used screening method for cervical cancer for several years. In 1988, the Bethesda system was adopted to reduce widespread confusion among laboratories and clinicians (National Cancer Institute Workshop, 1989). The system has been revised in 1991, and again in 2001, based on actual laboratory and clinical experience after its implement (Bethesda Workshop, 1992; Solomon et al., 2002). Major difference of Bethesda system is the introduction of squamous intraepithelial lesions (SIL) terminology in place of cervical intraepithelial neoplasia (CIN) of the World Health Organization (WHO)