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 neoplasia screening after increasing use of this technology.


METHODS
Cytological reports of 103,057 Siriraj-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 ± 12.2 yr, p <0.001), and their specimens had much lower proportion of unsatisfactory slides (OR=0.06, 95%CI 0.04-0.09) with comparable detection rates (3.96% vs 3.70%, p=0.052) but different proportions of various cytological abnormalities (p<0.001). The 2007-2009 Siriraj-LBC had a negative predictive value (NPV) for cervical 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 cells of undetermined significance (ASCUS), low-grade squamous intraepithelial lesion (LSIL), atypical squamous cells cannot exclude HSIL (ASC-H), high-grade squamous intraepithelial lesion (HSIL), atypical glandular cells (AGC), to squamous cell carcinoma (SCC), respectively. The PPVs for CIN2+ in ASCUS and LSIL were comparable, 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 similar management; other cytological abnormalities need immediate evaluation.
Department of Obstetrics and Gynecology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok, Thailand E-mail : chaopotong@yahoo.co.th.
Suthi
S
Sangkarat
Somsak
S
Laiwejpithaya
Manee
M
Rattanachaiyanont
Pattama
P
Chaopotong
Mongkol
M
Benjapibal
Weerasak
W
Wongtiraporn
Sujera
S
Laiwejpithaya
D000328:Adult; D002294:Carcinoma, Squamous Cell / Q000175:diagnosis / Q000473:pathology; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D006801:Humans; D018307:Neoplasms, Squamous Cell / Q000175:diagnosis / Q000473:pathology; D002583:Uterine Cervical Neoplasms / Q000175:diagnosis / Q000473:pathology; D014626:Vaginal Smears / Q000379:methods; D002578:Uterine Cervical Dysplasia / Q000175:diagnosis* / Q000473:pathology*