Marianne U. Prey

The AutoPap system for primary screening in cervical cytology. Comparing the results of a prospective, intended-use study with routine manual practice.

OBJECTIVE To evaluate the effectiveness of the AutoPap System in detecting abnormal and normal cervical smears when used in a primary screening/quality control mode, as compared with currently established laboratory practices. STUDY DESIGN Slides were obtained prospectively and were initially processed in the routine fashion with cytotechnologist screening followed by 10% random quality control rescreening. Slides were then processed on the AutoPap System and allocated into the following groups: (1) approximately 25% of the lowest-ranking slides were placed in the laboratorys archives as within normal limits; (2) the remaining approximately 75% of slides were subjected to manual screening. Approximately 15% of the highest-ranking slides in this group underwent quality control rescreening. For each slide needing manual screening, the cytotechnologist was supplied with a report giving the ranking score of that slide. All discrepant slides for either adequacy or diagnosis were subjected to a truth-determination process. The results obtained from the two arms of the protocol were then compared. RESULTS The AutoPap System-assisted arm of the study was superior to the current practice arm for the identification of abnormal slides at the level of atypical squamous cells of undetermined significance and above (ASCUS+), low grade squamous intraepithelial lesion (LSIL) and higher LSIL+. AutoPap System-assisted practice was equivalent to current practice for the identification of unsatisfactory and satisfactory but limited by slides. All results showed statistical significance. In addition, AutoPap System-assisted practice in the study indicated improved specificity of diagnosis. CONCLUSION AutoPap System-assisted practice shows superior sensitivity and specificity when compared to current practice. Its clinical use as a primary screening device should improve the overall practice of cervical cytology as well as provide potential enhancement in overall laboratory productivity.

Epithelial Cell Abnormalities: Squamous

Our understanding of preinvasive HPV-associated squamous lesions supports only two conceptual divisions: HPV infection and true precancer. Transient infections generally regress over the course of 1–2 years, and lesions with HPV persistence are associated with an increased risk of developing a cancer precursor (precancer) or invasive cancer. This concept led to the introduction of the two-tiered nomenclature of low-grade squamous intraepithelial lesion (LSIL) and high-grade squamous intraepithelial lesion (HSIL), by the Bethesda System (TBS) in 1988. The 2014 Bethesda update maintains this dichotomous reporting terminology for the squamous intraepithelial lesions. Since the focus of cervical cancer screening is primarily the detection of HSIL, this chapter has been substantially expanded to include problematic patterns and mimics that may lead to locator and/or interpretation errors of non-neoplastic changes as HSIL/ASC-H or vice versa.

Cytologic features of high-grade squamous intraepithelial lesion in ThinPrep Papanicolaou test slides: comparison of cases that performed poorly with those that performed well in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology

CONTEXT Conventional Papanicolaou (Pap) test slides of high-grade squamous intraepithelial lesions (HSILs) that are frequently misdiagnosed are known to have relatively few dysplastic cells. Whether this is true of cases of HSIL in ThinPrep Pap Test specimens is not known. OBJECTIVE To determine if cases of HSIL in ThinPrep specimens that are frequently missed have relatively few dysplastic cells. DESIGN The cytologic features of 16 ThinPrep cases of HSIL that performed poorly in the College of American Pathologists Interlaboratory Comparison Program were compared with 22 ThinPrep Pap Test cases that performed extremely well. RESULTS Significantly more cases that performed poorly had fewer than 250 dysplastic cells (13/16) than cases that performed well (3/22) (P <.001). CONCLUSION ThinPrep Pap Test cases with a diagnosis of HSIL that performed poorly in this program had significantly fewer dysplastic cells than those that performed well.

Cytologic Features of High-Grade Squamous Intraepithelial Lesion in Conventional Slides: What Is the Difference Between Cases That Perform Well and Those That Perform Poorly?

CONTEXT Previous studies have suggested that cases of high-grade squamous intraepithelial lesion in conventional smears and in ThinPrep specimens that are frequently misinterpreted as normal have relatively few small and hypochromatic dysplastic cells. OBJECTIVE To determine the cytologic differences between conventional Papanicolaou slides of high-grade squamous intraepithelial lesion that perform poorly and those that perform well. DESIGN We compared the cytologic features of 22 cases of conventional smears with high-grade squamous intraepithelial lesion that performed poorly in the College of American Pathologists Interlaboratory Comparison Program in Gynecologic Cytology with 45 cases of conventional smears that performed extremely well. RESULTS Cases that performed poorly were significantly more likely to have 50 or fewer single dysplastic cells (P = .003) and to have only small dysplastic cells (P = .01). Cases that performed well were also more likely to have more than 500 dysplastic cells (P = .002), to exhibit the presence of large dysplastic cells (P < .001), and to be keratinized (P = .03). Hypochromasia and the number of groups of dysplastic cells were not correlated with performance. CONCLUSIONS Conventional smears with high-grade squamous intraepithelial lesion with 50 or fewer single dysplastic cells, no large dysplastic cells, and lacking keratinization are highly associated with poor performance in this program.

The 2001 Bethesda system: Terminology for reporting results of cervical cytology

The Bethesda System for reporting the results of cervical cytology was introduced in 1988 and revised in 1991 using the actual laboratory and clinical experience with the system. After 10 years of widespread use and advances in biologic understanding of cervical neoplasia, it was felt important to reexamine this terminology. After extensive internet web-based discussion groups on various aspects of the System, a workshop was held at the National Cancer Institute in Bethesda, Maryland, with participation from a broad range of constituents including cytologists, pathologist, clinicians, epidemiologists, patient advocates, and attorneys. This consensus statement is the report of this workshop. The following table (Table 1) is an abstract of the consensus statement.

Scientific issues related to the cytology proficiency testing regulations

The member organizations of the CETC feel strongly that there are significant flaws associated with the proposed proficiency test and its implementation. The most immediate modifications include lengthening the required testing interval, utilizing stringently validated and continuously monitored slides, changing the grading scheme and changing the focus of the test from individuals to laboratory level testing, as described above. Integration of new computer-assisted and location-guided screening technologies into the testing protocol is necessary for the testing program to be compliant with the current CLIA law. The regulation also needs to be flexible enough to accommodate new technologies that are implemented in laboratory practice, education and administration of the test. The changes recommended in this document address the most immediate technical and scientific concerns with the current implementation of PT for gynecologic cytology. The CETC will be submitting a subsequent document, following full review of the current regulations, with recommendations for changes, justifications and impact.

Cytologic features of squamous cell carcinoma in ThinPrep slides: evaluation of cases that performed poorly versus those that performed well in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology

CONTEXT Although the cytologic features of squamous cell carcinoma in ThinPrep specimens are well known, whether these features are different in cases that are easily identified than in cases that are more difficult to identify is not known. OBJECTIVE To determine the cytologic features of squamous cell carcinoma in ThinPrep specimens that are easy to identify versus those that are difficult. DESIGN The cytologic features of 6 cases of squamous cell carcinoma that performed poorly in the College of American Pathologists Interlaboratory Comparison Program were compared with 14 cases that performed extremely well. RESULTS After evaluation of multiple criteria, 7 different cytologic features were analyzed based on review by a consensus panel blinded to the performance of the cases. The feature that was most strongly associated with cases that performed poorly was the presence of Trichomonas vaginalis (5/6 [83%] vs 0/14; P <.001). The presence of marked nuclear pleomorphism was more common in cases that performed well (4/14 [28%] vs 0/6; P =.27), but was not significant. The number of tumor cells, the number of normal cells, and the presence of keratinization, pleomorphism, nucleoli, and diathesis were not significant. The most common misdiagnosis after Trichomonas vaginalis was reparative change. CONCLUSIONS The presence of Trichomonas is characteristic of cases of squamous cell carcinoma in ThinPrep slides that are often misdiagnosed in this program. While Trichomonas is identified by participants in some of these cases, a significant percentage of participants interpreted the findings as reparative, without identifying the organism. These results emphasize the importance of distracting factors, whether identified or not, in evaluating gynecologic cytology.

Non-Neoplastic Findings

The category “negative for intraepithelial lesion or malignancy” is used for specimens that show a spectrum of nonneoplastic changes, including those associated with protective and reactive responses to inflammation, hormonal alterations, and colonizing or infectious organisms. Recognition of the wide variety of normal cellular presentations is key for the accurate discrimination from neoplastic conditions. Many characteristic patterns of reaction in normal cells can be important clues to the underlying causative process. Some of these patterns have features which are also seen in neoplasia, hence recognition of the key reactive changes is essential for overall accuracy. An expanded variety of “normal” findings as well as non-neoplastic mimics of classic epithelial abnormalities are included in this chapter, providing a more complete representation of the morphologic variations that can be encountered in cervical cytology preparations.

Computer-Assisted Interpretation of Cervical Cytology

Automated screening devices have the potential to increase both the sensitivity and the specificity of the cervical cancer screening process. In addition, productivity gains may be achieved with their use. In the era of HPV vaccine use, when prevalence of high-grade squamous intraepithelial lesions in the population is expected to decline, the sensitivity of manual screening will also decline. Thus, automation with its potentially superior sensitivity for rare-event detection may play an important role in morphology-based screening and triage. The increase in the prevalence of disease as presented to the screener via focused selection of important fields of view, or via selection of high-risk slides for manual review, has the potential to maintain the level of sensitivity needed to continue effective manual-based morphologic screening. Several new US Food and Drug Administration approvals in the field of automated cervical cytology screening have occurred in the past decade. These have included the so called “location-guided screening” devices that identify areas at highest risk for containing potential abnormalities—essentially providing a prescreened slide. This chapter provides an overview of the currently used systems and updates recommendations, which now include the reporting items for “location-guided screening” devices in addition to those previously covered in the second edition of this atlas.