ThinPrep Pap Test. Accuracy for glandular disease.
ABSTRACT Although the ThinPrep Pap Test is replacing conventional Pap smears in many clinical practices, experience with the identification of glandular lesions is limited. In this study, ThinPrep cytology of glandular lesions was evaluated in a large, inner city teaching hospital with high rates of glandular abnormality.
Six months of ThinPrep diagnoses in 1998, following nearly 100% conversion of the laboratory to the ThinPrep Pap Test, were compared to January-December 1997 conventional smear diagnoses for glandular disease. Biopsy confirmation was evaluated for these cases. Findings on all biopsy-confirmed glandular cases were also compared to findings on cytology.
Similar overall rates of glandular cytology were found. For conventional smears (12 months), 46 cases were diagnosed out of 43,289 smears (0.11%). For ThinPrep cytology (six months), 36 cases were diagnosed out of 25,783 slides (0.14%, P = NS). In the year 1997, 9 biopsy-confirmed conventional smear diagnoses of adenocarcinoma in situ (AIS) or adenocarcinoma were noted versus 10 for six months of 1998 for the ThinPrep method. A statistically significant reduction in the number of miscellaneous nonglandular (squamous) biopsy diagnoses were found with ThinPrep glandular cytology (14 vs. 4 cases, P < .05). For known biopsy-confirmed glandular cases of AIS or adenocarcinoma, a statistically significant reduction in the cytology false negative rate was noted with the ThinPrep method (17 vs. 4 cases, P < .02).
The ThinPrep method provides more accurate diagnoses of glandular disease, with an increase in both sensitivity and specificity for glandular lesions.
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ABSTRACT: BACKGROUND The Royal College of Pathologists of Australasia Cytopathology Quality Assurance Program offers external testing in gynecologic cytology to Australasian and international laboratories. Laboratory interpretation of conventional Papanicolaou (Pap) smears is compared with interpretation of liquid-based cervical cytologic (ThinPrep) samples.METHODS Conventional Pap smears and ThinPrep samples were distributed to participating laboratories annually over 9 years (from 2004 to 2012), and a range of entities was tested. Target responses and major error rates and diagnostic trends over time were explored.RESULTSIn total, 23,373 conventional Pap smears and 14,104 ThinPrep samples were reported. Both Australasian (P = .003) and international (P < .001) laboratories achieved a higher percentage of the target diagnosis of squamous dysplasia with ThinPrep samples. Australasian laboratories more accurately diagnosed endocervical adenocarcinoma in situ with conventional smears (P = .036), whereas international laboratories performed better with ThinPrep samples (P = .006). Sampling of the lower uterine segment was more accurately diagnosed by both Australasian (P < .001) and international (P = .001) laboratories using conventional Pap smears. Significant improvements in achieving the target diagnosis over time for squamous dysplasias using both modalities were observed for Australasian and international laboratories (P < .001 for both). There was improvement in diagnosing high sampling using ThinPrep for both groups (P = .001 and P = .015, respectively). Australasian performance declined over time in reaching the target of normal (no infections) for both conventional (P = .001) and ThinPrep (P < .001) techniques and for international laboratories with the ThinPrep technique (P < .001).CONCLUSIONS Participation in external proficiency testing in cervical cytology allows an analysis of performance, the identification of areas of diagnostic difficulty, a review of trends over time, and the highlighting of topics for ongoing education. Cancer (Cancer Cytopathol) 2014. © 2014 American Cancer Society.Cancer Cytopathology 12/2014; 123(2). DOI:10.1002/cncy.21498 · 3.81 Impact Factor