Assessment of the validity of Pap smear cytology in the diagnosis of cervical intraepithelial neoplasia in Erbil city

Abstract

Background and objectives: Cervical smears can reduce both incidence and mortality rates from invasive cervical cancer. Despite its success, cervical cytology has important limitations. The aim of this study is to assess the validity of conventional Pap smear in diagnosis of cervical intraepithelial neoplasia in Erbil through comparison with colposcopy with or without cervical biopsy. Methods: A hospital-based study was carried out in Erbil Maternity Hospital from the 1st May to 31st December 2008. The study sample included 336 women attending the breast disease center for routine breast examination. Cervical Pap smear followed by colposcopic examination was done for each woman on the same day. Cervical punch biopsy was taken for those with abnormal colposcopic findings. Colposcopy with or without biopsy was considered as a gold standard diagnosis of cervical intraepithelial neoplasia (CIN). Results: Out of 336 women, 48 (14.3%) had abnormal cervical smear results, of which 43 (12.8%) of the total had low-grade cervical lesions and 5 (1.5%) of the total had high-grade cervical lesions. Colposcopy-directed biopsy revealed that 69 (20.5%) had abnormal findings of which 65 (19.3%) women had CIN I and 4 (1.2%) of the total had CIN II and III. The sensitivity and specificity of the cervical smear were 62.3% and 98.1%, respectively. The positive predictive value was 89.6% while the negative predictive value was 91%. The false negative percentage was 37.7%. The accuracy of the test was 90.8% and the degree of agreement between Pap smear and colposcopy with biopsy results was 90.2%. Conclusion: The high accuracy of cervical smear in this study and high agreement rate between cervical cytology and colposcopy indicates that conventional Pap smear is an important dependable screening test in spite of its low validity in terms of its sensitivity.