Comparison of Visual Inspection with Acetic Acid (VIA) and Papanicolau (PAP) Smears for Cervical Cancer Screening in Nakhonpathom Hospital

Abstract

Objective : To compare the sensitivity, specificity, positive and negative predictive values (PPV and NPV), accuracy, false positive rate and false negative rate of visual inspection with acetic acid (VIA) and Pap smear.

Materials and method : This was a cross-sectional study. A total of 1,000 women aged 20-60 years who attended to the outpatient gynecologic clinic in Nakhonpathom hospital from 1st April 2010 to 31^st December 2010 were examined by PAP smear, VIA and colposcopy. Distinct acetowhite areas touching the squamo-columnar junction (SCJ) were categorized as VIA positive cases. ASCUS or worse lesions by cytology were considered as positive smears . Those women who showed positive test result with either VIA or PAP smear or both tests were further subjected to colposcopy direct biopsy and histology were taken as gold standard to compare the performance of VIA and PAP. Those for whom histology revealed no pathology or reactive/reparative change or inflamation were considered as negative and HPV or worse lesions by pathology were considered as positive.

Result : Of the total of 1,000 women , PAP smear was positive (for atypia or worse lesions) in 234 women (23.4%), VIA was positive in 378 women (37.8%) and gold standard was positive in 269 women (26.9%), These were 97 cases of HPV, 78 cases of CIN1, 22 cases of CIN2, 49 cases of CIN3, 16 cases of carcinoma in situ, 5 cases of SCC and 2 cases of AIS. The sensitivity, specificity, PPV, NPV, accuracy, false positive rate and false negative rate of the VIA and the Pap smear were 93.3, 82.6, 66.4, 97.1, 85.5, 17.4 and 6.7% ; 64.3, 91.7, 73.9, 87.5, 84.3, 8.3 and 35.7%, respectively.

Conclusion: Screening for cervical precancerous and cancerous lesions using visual inspection aided by acetic acid may be a suitable low-cost and a feasible alternative modality for control of cervical cancer in a resource poor setting.