The ASCUS : SIL ratio and the reference laboratory pathologist

The value of monitoring human papillomavirus DNA results for Papanicolaou tests diagnosed as atypical squamous cells of undetermined significance: a College of American Pathologists Q-Probes study of 68 institutions

CONTEXT

Papanicolaou (Pap) tests are often diagnosed as atypical squamous cells of undetermined significance (ASC-US). Human papillomavirus (HPV) DNA testing has been proposed as a quality metric for this diagnosis.

OBJECTIVE

To measure the frequency of HPV positivity in Pap tests diagnosed as ASC-US and to examine laboratory variables that are associated with institutional deviation from the mean percent of HPV positivity.

DESIGN

As part of a College of American Pathologist Q-Probes program, 68 participating laboratories retrospectively identified approximately 50 consecutive ASC-US Pap tests that had HPV testing results.

RESULTS

The mean percentage of HPV positivity for ASC-US was 43.74% among institutions surveyed, but it had a broad distribution, with an SD of 17.77%. Associations were found for lower difference of the institutional mean from the surveyed interinstitutional mean percentage of positive HPV with (1) higher numbers of Pap tests in the past year that had HPV testing, (2) in-house HPV testing, and (3) teaching hospitals. All 3 factors correlated with a larger volume of Pap tests per institution. An association was found between patient age and the probability of a positive HPV result, indicating a dependence upon prevalence of HPV.

CONCLUSIONS

Larger volumes of Pap tests may offer an opportunity to gain greater comfort in interpreting Pap tests. While there is significant variability in interinstitutional HPV-positive rates in ASC-US Pap tests, monitoring the HPV-positive rate in ASC-US Pap tests is a valuable broad measure of quality. Performance beyond 2 SDs of the mean should prompt reassessment of diagnostic criteria used in the evaluation of Pap tests and/or investigation of the prevalence of HPV positivity in the population from which the Pap tests are obtained.

[Contribution of HPV sequences detection in cervical carcinoma screening]

At the present time, Human Papillomaviruses (HPV) is a leading cause of squamous intraepithelial lesions (SIL) and invasive carcinoma of the cervix. The aim of this article was to review the main taxonomic and epidemiologic data on HPV infection and to assess the potential clinical implications of the different HPV tests in staging women with borderline cytologies (ASC-US; ASC-H; LSIL); for follow-up after treatment of high-grade cervical intraepithelial neoplasia (CIN), for primary screening as the sole screening modality, or in association with cytology.

Human papillomavirus testing as a cytology gold standard: comparing Surinam with the Netherlands

Polymerase chain reaction to detect high-risk human papillomavirus has been suggested as a gold standard for cytology. The Netherlands and Surinam were prospectively compared in regard to the proportions of Negative, Atypical Squamous Cells of Undetermined Significance, and Squamous Intraepithelial Lesion smears that had detectable high-risk human papillomavirus. For the Netherlands, 14 600 negative, 270 Atypical Squamous Cells of Undetermined Significance and 120 Squamous Intraepithelial Lesion smears were evaluated by polymerase chain reaction. For Surinam, 150 negative, 50 Atypical Squamous Cells of Undetermined Significance, and 150 Squamous Intraepithelial Lesion smears were evaluated by polymerase chain reaction. In all, 4% of Dutch and 80% of Surinamese negative smears had detectable high-risk human papillomavirus (chi2=1313, P<0.00001). In total, 41.9% of Dutch and 84% of Surinamese Atypical Squamous Cells of Undetermined Significance smears had detectable high-risk human papillomavirus (chi2=28, P<0.00001). Totally, 67.5% of Dutch and 94% of Surinamese SIL smears had detectable high-risk human papillomavirus (chi2=30, P<0.00001). The Negative: Atypical Squamous Cells of Undetermined Significance odds ratio was 0.058 for the Netherlands and 0.762 for Surinam (chi2homog=31, P<0.00001). The Negative: Squamous Intraepithelial Lesion odds ratio was 0.020 for the Netherlands and 0.255 for Surinam (chi2homog=31, P<0.00001). The Atypical Squamous Cells of Undetermined Significance: Squamous Intraepithelial Lesion odds ratio was 0.347 for the Netherlands and 0.335 for Surinam (chi2homog=0.005, P>0.75). Human papillomavirus DNA testing may not be a suitable gold standard in general because its use would make specificity and sensitivity prevalence-dependent. A new statistic, the percent of Negative pap smears with detectable high-risk human papillomavirus, is posited, which may be important if human papillomavirus DNA testing is used clinically.