Performance of Siriraj Liquid-Based Cytology: a Single Center Report Concerning over 100,000 Samples

Background: To evaluate the performance of Siriraj liquid-based cytology (LBC) for cervical neoplasiascreening after increasing use of this technology. Materials and
Methods: Cytological reports of 103,057Siriraj-LBC specimens obtained in 2007-2009 were compared with those of 23,676 specimens obtained in 2006.
Results: Comparing with the year 2006, the 2007-2009 patients were slightly older (43.4±12.yr vs 42.7±12.2yr, p <0.001), and their specimens had much lower proportion of unsatisfactory slides (OR=0.06, 95%CI0.04-0.09) with comparable detection rates (3.96% vs 3.70%, p=0.052) but different proportions of variouscytological abnormalities (p<0.001). The 2007-2009 Siriraj-LBC had a negative predictive value (NPV) forcervical intraepithelial neoplasia 2+ (CIN2+) of 97.6% and an overall positive predictive value (PPV) of 43.9%.The PPV for CIN2+ varied with types of abnormal cytology, from 13.7% to 93.8% in atypical squamous cellsof undetermined significance (ASCUS), low-grade squamous intraepithelial lesion (LSIL), atypical squamouscells cannot exclude HSIL (ASC-H), high-grade squamous intraepithelial lesion (HSIL), atypical glandularcells (AGC), to squamous cell carcinoma (SCC), respectively. The PPVs for CIN2+ in ASCUS and LSIL werecomparable, but the PPV for CIN1 was higher for LSIL than for ASCUS (41.63% vs 16.32%).
Conclusions:Siriraj-LBC has demonstrated a stable detection rate and NPV for CIN2+ of >95% since the first year of use.The comparable PPVs for CIN2+ of ASCUS and LSIL suggests that these two conditions may undergo similarmanagement; other cytological abnormalities need immediate evaluation.