The promise and risk of a new technology: The Lehigh Valley Hospital's experience with liquid-based cervical cytology

Cytomorphological characteristics of glassy cell carcinoma of the uterine cervix: histopathological correlation and human papillomavirus genotyping

A retrospective analysis was performed to describe the cytomorphological and histopathological findings and human papillomavirus (HPV) genotypes for glassy cell carcinoma (GCC) of the uterine cervix. Five cases of cervical GCC, in which the glassy cell features constituted at least 95% of the specimen, were included. Four patients had stage IIB GCCs and one had stage IIIB GCC. All patients underwent concurrent chemoradiation therapy. Based on pretreatment cytology, only 1 of the 5 cases was correctly diagnosed as GCC. The remaining cases were diagnosed as carcinoma of undetermined type, adenocarcinoma, poorly differentiated carcinoma, or unsatisfactory for evaluation. Cytological specimens had moderate cellularity and contained small clusters of tumor cells admixed with amphophilic, granular tumor diathesis. The tumor cells possessed large, round to oval nuclei and abundant, granular, ground-glass cytoplasm. The nuclei exhibited prominent eosinophilic nucleoli. The cytoplasm displayed sharp margins and molding, resulting in “intercellular windows” between neighboring attached cells. HPV genotyping revealed that high-risk HPV types 18, 16, and 31 were detected in 3, 1, and 1 cases, respectively. Consistent with this finding, all cases exhibited block p16 positivity, confirming the association of HPV infection with GCC. In conclusion, a distinct cytoplasmic margin, the characteristic histopathological feature of GCC, was observed in liquid-based cytological preparations. We suggest that sharp cytoplasmic outlines with molding and intercellular windows are characteristic cytomorphological features of GCC. Detection of high-risk HPV in all cases strongly supported the notion that high-risk HPV is involved in the pathogenesis of GCC.

Cytologic detection of cervical abnormalities using liquid-based compared with conventional cytology: a randomized controlled trial

OBJECTIVE

To compare test positivity rates of liquid-based and conventional cytology.

METHODS

This study was a cluster randomized controlled trial with family practice as the unit of randomization, performed within the Dutch national cervical screening program. Women aged 30-60 years (n=89,784) recruited from 246 family practices were included. One-hundred twenty-two practices (49,222 individuals) were randomly assigned to the experimental arm, and 124 practices (40,562 participants), to the conventional arm. Inclusion was performed during a 3-year period between April 2003 and July 2006. Cytologic test positivity rates of liquid-based compared with conventional cytology was compared in terms of crude and adjusted odds ratios, applying a per-protocol analysis.

RESULTS

Crude ratios of the odds of test positivity rates of liquid-based compared with conventional cytology for atypical squamous cells of undetermined significance or more severe, low-grade squamous intraepithelial lesion or more severe, and high-grade squamous intraepithelial lesion or more severe were 0.95 (95% confidence interval [CI] 0.82-1.10), 1.00 (95% CI 0.83-1.20), and 0.97 (95% CI 0.77-1.22), respectively. Liquid-based cytology resulted in fewer unsatisfactory tests (odds ratio 0.30, 95% CI 0.23-0.38). The results did not change when the odds ratios were adjusted for age, study site, study period, and urbanization level. Of 128 women screened with liquid-based cytology, one unsatisfactory preparation is avoided.

CONCLUSION

This study found no statistically significant difference in cytologic test positivity rates between liquid-based and conventional cytology. However, liquid-based cytology resulted in significantly fewer unsatisfactory tests.

CLINICAL TRIAL REGISTRATION

Nederlands Trial Register, www.trialregister.nl, NTR1032

LEVEL OF EVIDENCE

I.

Longitudinal clinical evaluation of a novel antibody cocktail for detection of high-grade squamous intraepithelial lesions on cervical cytology specimens

CONTEXT

Although cervical cancer screening by cytology is successful, the test continues to show relatively poor operating characteristics. Cell cycle markers may enhance detection of high-grade squamous intraepithelial lesions.

OBJECTIVE

To determine the clinical usefulness of ProExC, an immunocytochemical assay for cell cycle components, performed on routine cervical cytology samples.

DESIGN

Cervical cytology samples were collected using the SurePath method. Residual cells remaining after preparation of the Papanicolaou-stained slide were used to make a second slide for ProExC staining using an indirect polymer-based immunoperoxidase method. Only adequately cellular slides were evaluated for the presence of nuclear staining within cytologically abnormal epithelial cells. Results were correlated with clinical follow-up.

RESULTS

Six hundred twenty-four samples were satisfactorily cellular and stained. Correlation with clinical follow-up for subsequent cervical intraepithelial neoplasia 2+ on biopsy/high-grade squamous intraepithelial lesion on cytology (CIN 2+/HSIL) showed that 434 results were true negative, 78 true positive, 18 false-negative, and 94 false-positive, resulting in a sensitivity/specificity of 81%/82%. When ProExC results were combined with any level of cytologic atypia, sensitivity for CIN 2+/HSIL was 92% and specificity was 84%.

CONCLUSIONS

ProExC shows promise as an aid in enhancing the sensitivity and specificity of cervical cytology for subsequent CIN 2+/HSIL and may be useful in identifying those cervical lesions most apt to progress.

A rare case of primary lung adenocarcinoma detected by routine liquid-based cervical cytology

Cervical cytology is mainly used for the screening and detection of early cervical cancers and its precursors. Rarely, detection of malignant cells in cervical cytology specimens is the first manifestation of an extrauterine (EU) malignancy. We report a case of a 49-year-old female in which adenocarcinoma initially diagnosed on routine, liquid-based cervical cytology led to the detection of a primary lung cancer.

Direct comparison of liquid-based and conventional cytology in a South African screening trial

Our study directly compares the performance of liquid-based (LBC) and conventional cytology for detecting high-grade cervical intraepithelial neoplasia and cancer (CIN 2+) in high-risk, previously unscreened women. As part of a larger randomized clinical trial assessing the efficacy and safety of a "screen and treat" program for cervical cancer prevention, 5,652 South African women, aged 35 to 65 years, were screened using either ThinPrep or conventional Papanicolaou cytology. The cytology method used (i.e., ThinPrep or conventional) was rotated on a 6-month basis for the duration of the study. Directly following collection of the cytology specimen, all women underwent colposcopy with endocervical curettage and biopsy of all colposcopic abnormalities. Assessment of cytology and histology results was blinded and results were compared using histology-confirmed CIN as the "gold standard." The accuracy of LBC and conventional cytology was statistically equivalent, although the sensitivity of conventional cytology was at least 5 percentage points higher at all cutoff levels. For example, at a cytology cutoff level of low-grade squamous intraepithelial lesion, the sensitivity of LBC was 60.3% for CIN2+ vs. 69.1% for conventional cytology and specificity was 94.1% and 94.5%, respectively. LBC specimens were significantly less likely to be "satisfactory-but-limited-by" (6.5% vs. 27.9%) but significantly more likely to be unsatisfactory (2.2% vs. 0.8%). Thus, in this high-risk population, the sensitivity of LBC is no greater than the sensitivity of conventional cytology. Because of the higher unit cost of LBC, low resource settings should carefully consider the potential benefits and drawbacks of LBC before adopting this new technology.

Effect of study design and quality on unsatisfactory rates, cytology classifications, and accuracy in liquid-based versus conventional cervical cytology: a systematic review

BACKGROUND

Liquid-based cytology is reported to increase the sensitivity of cervical cytology and the proportion of slides that are satisfactory for assessment, in comparison with conventional cytology. Although some countries have changed to liquid-based cytology for cervical screening, controversy remains. We reviewed the published work to assess the performance of liquid-based cytology relative to conventional cytology in primary studies assessed to be of low, medium, or high methodological quality.

METHODS

56 primary studies were reviewed and assessed with strict methodological criteria. Liquid-based cytology and conventional cytology were compared in terms of the percentage of slides classified as unsatisfactory, the percentage of slides classified in each cytology category, and the accuracy of detection of high-grade disease. Data were examined for studies overall and in strata to examine the effect of study quality on results.

FINDINGS

The median difference in the percentage of unsatisfactory slides between liquid-based cytology and conventional cytology was 0.17%. Only one small study was a randomised controlled trial. The classification of high-grade squamous epithelial lesion varied according to study quality (p=0.04), with conventional cytology classifying more slides in this category than did liquid-based cytology in high-quality studies (n=3) only. In medium-quality (n=30) and high-quality studies, liquid-based cytology classified more slides as atypical squamous cells of unknown significance than did conventional cytology when compared with low-quality studies (n=17; p=0.05). Only four studies provided sufficient verified data to allow estimation of sensitivity and specificity and comparison of test accuracy.

INTERPRETATION

We saw no evidence that liquid-based cytology reduced the proportion of unsatisfactory slides, or detected more high-grade lesions in high-quality studies, than conventional cytology. This review does not lend support to claims of better performance by liquid-based cytology. Large randomised controlled trials are needed.

An evaluation of liquid-based cytology and human papillomavirus testing within the UK cervical cancer screening programme

The aim of this study is to evaluate different options for introducing liquid-based cytology (LBC) and human papillomavirus (HPV) testing into the UK cervical cancer screening programme. These include options that incorporate HPV testing either as a triage for mild and borderline smear abnormalities or as a primary screening test. Outcomes include the predicted impact on resource use, total cost, life years and cost–effectiveness. Extensive sensitivity analysis has been carried out to explore the importance of the uncertainty associated with disease natural history and the impact of screening. Under baseline assumptions, the cost–effectiveness of different options for introducing LBC appears favourable, and these results are consistent under a range of assumptions for its impact on the diagnostic effectiveness of cytology. However, if we assume a higher marginal cost of LBC in comparison to conventional methods, primary smear testing options are predicted to be more cost-effective without LBC. Combined LBC primary smear and HPV testing with a 5-year interval is similar in both cost and effectiveness to the other 3-yearly options of primary smear testing or primary HPV testing alone. However, both primary HPV testing and combined options would give rise to a far greater risk of inappropriate colposcopy throughout a woman's lifetime.

Can Human Papillomavirus DNA Testing Substitute for Cytology in the Detection of High-Grade Cervical Lesions?

Context.—High-risk human papillomaviruses (HPVs) are causal factors of cervical carcinomas.

Objective.—To evaluate the sensitivity and efficiency of HPV DNA testing in comparison with conventional cytology for detection of cervical intraepithelial neoplasia (CIN) and cancer.

Design.—Both testing procedures were administered to 593 women, aged 14 to 88 years (average, 41.7 years), who were referred for abnormal cytology from January 2000 through December 2001 at Korea University Guro Hospital (Seoul, Korea). After histologic confirmation by either colposcopically directed biopsy or endocervical curettage, the efficiency of the detection methods for high-grade cervical lesion was evaluated for the following 3 data sets: HPV DNA testing, conventional cytology, and the 2 tests combined.

Results.—The sensitivity, specificity, and positive predictive, and negative predictive values for the detection of CIN 2 or higher were 92.4%, 52.4%, 49.3%, and 93.2% for HPV DNA testing; 76.3%, 65.8%, 52.8%, and 84.7% for cytology; and 97.8%, 36.7%, 49.2%, and 97.3% for the combined tests. Among the 151 patients diagnosed with CIN 2 or CIN 3, 137 patients (90.7%) were HPV positive, 116 patients (76.8%) were proven to have abnormal cytology, and 147 patients (97.6%) were positive for either HPV DNA testing or cytology. The sensitivity values for HPV DNA testing and cytology were 97.9% (46/47) and 74.5% (35/47), respectively, for invasive cervical cancer detection, and the combined tests showed 100% (47/47) sensitivity. Depending on the patient's age and the grade of the cervical lesion, HPV DNA testing proved to be significantly more sensitive than cytology for the primary detection of cervical abnormalities (P < .001).

Conclusion.—Human papillomavirus DNA testing for the detection of high-grade cervical lesions was more sensitive than cytology alone. In addition, the screening sensitivity can be further improved by combining cytology with HPV DNA testing. This approach is especially beneficial in detecting cancer precursors in women older than 60 years.

Cervical cytology automation: an update for 2003. The end of the quest nears?

The field of cytology automation, through long investigation, trial and error, and finally, commercial success and failure, has arrived at the first levels of the "grail" of improvements in accuracy and productivity in cervical cytology screening. It remains to be seen how much further the road will lead toward so-called "diagnostic" instrumentation that would actually provide us with a fully automated system of "specimen in-diagnosis out" with little, or no, human input. Will commercial ventures or academic institutions continue to support investigations to further the applications that have been developed to date? This remains to be seen and is directly dependent on parallel processes that are detailed elsewhere in this issue. Will HPV vaccines eliminate the need for screening? Possibly, but probably not for many years [70]. Will more sensitive and specific genetic or protein markers (or combinations thereof) be found to be more accurate and cost-effective? Certainly the possibility of mass screening by high-risk HPV DNA testing, as a viable alternative, is being discussed at present. Despite all of these uncertainties, the present (or nearly available) technology has the potential to improve the practice of cervical cytology. Improvements in accuracy that are necessary to provide the highest possible level of patient care and to protect practitioners from unreasonable levels of medico-legal risk are a reality. Improvements in productivity that are necessary to help in the impending labor shortage in the field of cytotechnology are also a reality. Automation is clearly the short-term solution to the most difficult of the challenges that we face.

Performance of ThinPrep liquid-based cervical cytology in comparison with conventionally prepared Papanicolaou smears: a quantitative survey

OBJECTIVES

The goal of this study was to evaluate the performance of ThinPrep, a liquid-based cytology preparation technique, in comparison with conventionally prepared Papanicolaou smears in detecting cervical pathology.

METHODS

Forty-seven English-language articles published between January 1990 and September 2002 were identified through Medline and manual searches. After elimination of 5 nonprimary articles, 10 unpaired studies, 5 descriptive articles with insufficient or no data, and 3 articles with data that could not be recast into a consistent format, there remained 24 usable articles. Seventeen articles contained data comparing ThinPrep with conventional cytology for 35172 patients; and 10 articles compared cytology with histology or other gold standard diagnoses for 21752 patients. Three of these articles contained both types of comparisons. The standard cytology classification into negative, atypical, low-grade (LGSIL) and high-grade (HGSIL) squamous intraepithelial lesions, and carcinoma was applied; other categorization schemes were recoded as necessary. Concordance estimates, based on five-way and dichotomous (normal/abnormal) classifications, were obtained from the 17 studies containing paired cytology data. Sensitivity and specificity rates were obtained from the 10 studies with paired cytology and histology data.

RESULTS

The two methods tend to agree in 89 and 92% of cases based on the five-level and dichotomous classifications, respectively. ThinPrep was reported as normal in 93.5% of cases of normal conventional smears. The remaining 6.5% of ThinPrep slides were classified as follows: atypical, 4.55%; LGSIL, 1.56%; HGSIL, 0.36%; invasive cancer, 0.007%. Sensitivity rates, relative to histology, were 68% (conventional) and 76% (ThinPrep), and specificity rates were 79% (conventional) and 86% (ThinPrep).

CONCLUSION

ThinPrep tends to be more sensitive and specific than conventional smears in detecting cervical dysplasia. The increased sensitivity of ThinPrep results in increased cytologic diagnosis of cervical atypia, LGSIL, HGSIL, and invasive cervical carcinoma.

ThinPrep detection of cervical and endometrial adenocarcinoma: a retrospective cohort study

BACKGROUND

The current study was performed to compare the accuracy of the ThinPrep trade mark Papanicoloau (Pap) test with that of the conventionally prepared Pap smear in detecting cervical and endometrial adenocarcinomas.

METHODS

The subject group consisted of all ThinPrep cases of atypical glandular cells of undetermined significance (AGCUS) or adenocarcinoma diagnosed between March 1998 and March 2000. Conventional smears collected between January 1996 and January 1998, before laboratory conversion to the ThinPrep system, comprised the control group. Histologic follow-up was obtained.

RESULTS

One hundred eighty-six (0.17%) of 112,058 ThinPrep Pap tests were interpreted as AGCUS/adenocarcinomas, compared with 77 (0.09%) of 83,464 conventional smears (P < 0.001). The overall sensitivity of a ThinPrep AGCUS/adenocarcinoma smear in detecting either cervical or endometrial adenocarcinoma was increased (72.0% vs. 41.5%; P < 0.001). The ThinPrep Pap test was more sensitive in detecting endometrial adenocarcinomas (65.2% vs. 38.6%; P = 0.010) and there was a trend for a higher sensitivity in detecting cervical adenocarcinomas (87.1% vs. 55.5%; P = 0.108).

CONCLUSION

The ThinPrep Pap test is a more sensitive method of detecting cervical and endometrial adenocarcinomas than the conventional Pap smear.

In vitro adjuncts to the pap smear

The Pap smear has been recognized widely as the most effective cancer screening test in the history of medicine. It is widely believed that the use of this test has been responsible for the drastic reduction in the incidence and mortality of cervical cancer in the United States, Canada, and much of Western Europe in the last 50 years. Several adjuncts to the Pap smear including liquid based cytology, computer-assisted screening, human papilloma virus and molecular testing are discussed.

Long-term follow-up of women with atypical squamous cells of undetermined significance (ASCUS)

ASCUS is the most common epithelial abnormality diagnosed in cytology laboratories in the US. Recently, the clinical importance of this diagnosis has been seriously questioned, with some investigators advocating elimination of this diagnostic category. This might be inappropriate if the ASCUS designation does define a population that is at significant risk for the development of dysplasia. Cytology and surgical pathology reports for all patients diagnosed as ASCUS in our laboratory during 1990 were reviewed. Patients with previous dysplasia or carcinoma were excluded from analysis. The pathology reports for the subsequent 9.1 yr were obtained and follow-up data collected. In 1990, 15,860 cervical cytology cases were examined in our laboratory. A diagnosis of ASCUS was made in 1,117 cases (7.0%). After excluding 345 patients with previous dysplasia or human papillomavirus-related diagnoses and 129 patients with no follow-up specimens, 643 study patients remained. Among these, the mean number of subsequent cervical smears was 4.3 (range, 1-18). Subsequent histologic material was available for 134 (20.8%) patients and the mean number of surgical specimens was 1.5 (range, 1-10). Squamous intraepithelial lesion (SIL) or dysplasia was subsequently diagnosed in 197 patients (30.6%). High-grade squamous intraepithelial lesion (HSIL) or at least moderate dysplasia was diagnosed in 64 patients (10.0%). In 21 cases (3.3%) the high-grade dysplasia developed more than 2 yr after the first ASCUS diagnosis. Follow-up disclosed no cases of invasive carcinoma. Among ASCUS patients followed for up to 9 yr, 20% develop only low-grade SIL or mild dysplasia and 10% develop HSIL or moderate or severe dysplasia. ASCUS should be retained as a diagnostic category since it identifies a significant percentage of patients who are at an increased risk for the development of cervical dysplasia.

Liquid-based cytology: is this the way forward for cervical screening?

Liquid-based cytology (LBC) is currently being marketed as an alternative methodology to replace the conventional PAP smear in cervical cytology. A substantial body of literature exists in support of LBC, some of which is at least partially sponsored by product manufacturers. The majority of published literature in support of LBC employs Bethesda reporting terminology. In this study we have analysed published raw data and presented this in NHSCSP terminology. Claims relating to sensitivity, specificity and smear adequacy have then been considered with reference to this data. Our analysis of existing data does not support the nationwide implementation of LBC at present. Further studies are recommended in order to evaluate the place of this technology within the NHSCSP.

[Liquid phase cytology in the primary screening for cervical cancer: a multicenter study]

The aim of this six-centre, split-sample study was to compare ThinPrep fluid-based cytology to the conventional Papanicolaou smear. Six Cytopathology laboratories and 35 Gynaecologists participated. 5428 patients met the inclusion criteria. Each cervical sample was used first to prepare a conventional Pap smear, then the sampling device was rinsed into a PreservCyt vial, and a ThinPrep slide was made. Screening of slide pairs was blinded. On initial screening, 29% more ASCUS and 39% more low-grade squamous intraepithelial lesions (LSIL) and more severe lesions (LSIL+) were detected on the ThinPrep slides than on the conventional smears (p = 0.001). Independent and consensus review confirmed 145 LSIL + diagnoses; of these, 18% more had been detected initially on the ThinPrep slides than on the conventional smears (p = 0.041). The ThinPrep Pap Test is more accurate than the conventional Pap Test and has the potential to optimize the effectiveness of primary cervical cancer screening.

Liquid-based cervical cytologic smear study and conventional Papanicolaou smears: a metaanalysis of prospective studies comparing cytologic diagnosis and sample adequacy

OBJECTIVE

We sought to evaluate the cytologic diagnosis and sample adequacy of the liquid-based cervical cytologic smear (ThinPrep) compared with that of the conventional Papanicolaou smear.

STUDY DESIGN

Prospective studies of ThinPrep and conventional Papanicolaou smears were analyzed for cytologic diagnosis and sample adequacy. Computerized databases, references in published studies, and index reviews published in English were used to identify direct-to-vial and split-sample clinical trials of cervical smears performed by conventional and liquid-based techniques. Only published studies that used the Bethesda system nomenclature with clearly documented outcome data were included. Each trial was assessed for the quality of its method, inclusion and exclusion criteria, adequacy of randomization, sampling protocols, definition of outcome, and statistical analyses.

RESULTS

Twenty-five studies met inclusion criteria for this review. Odds ratios with 95% confidence intervals were calculated for each outcome. Estimates of odds ratios and risk differences for dichotomous outcomes were calculated by use of random and fixed-effects models. Homogeneity was tested across the studies. Results indicate that the ThinPrep test is as good as or superior to the conventional Papanicolaou smear in diagnosing uterine cervical premalignant abnormalities. Also the ThinPrep test provides improved sample adequacy when compared with the conventional Papanicolaou test.

CONCLUSION

The ThinPrep test improved sample adequacy and led to improved diagnosis of low-grade and high-grade squamous intraepithelial lesions. However, there is no difference in the rate of atypical cells of undetermined significance diagnosis between ThinPrep and conventional smear groups. The added cost of ThinPrep cytologic screening and, hence, its cost-effectiveness are not evaluated in this study.

Should the cytologic diagnosis of "atypical squamous cells of undetermined significance" be qualified? An assessment including comparison between conventional and liquid-based technologies

BACKGROUND

The diagnosis of atypical squamous cells of undetermined significance (ASCUS) remains an enigma for the treating physician, because it encompasses both benign, reactive, as well as preneoplastic and possibly neoplastic conditions. To address this problem, The Bethesda System recommends qualifying the ASCUS diagnosis. This study analyzes the difference in the follow-up results between the various groups of patients with an ASCUS diagnosis as outlined by the Criteria Committee: favor premalignant (ASCUS-P), favor reactive (ASCUS-R), and unqualified (ASCUS-C). The outcome, based on follow-up biopsies and/or cytologies, for both the conventional Papanicolaou smear (CS) and liquid-based (LB) methodologies is compared.

METHODS

The CS and LB biopsies and/or cytologies included 590 patients and 137 patients, respectively, who had an initial diagnosis of ASCUS. The final outcome after subsequent biopsy and cytology within a 1-year period for each methodology was tabulated. Furthermore, the addition of qualifiers for each diagnosis was tabulated for both cytology and biopsy follow-up and compared between CS and LB technologies.

RESULTS

For CS, 29 patients (8.6%) were found to have squamous intraepithelial lesions (SIL) on subsequent cytologic smears, and 176 patients (63.7%) had SIL on biopsy follow-up. For LB, these numbers were 17 patients (19.1%) and 56 patients (65.1%), respectively. Regardless of the qualification used in the initial CS biopsy or cytology, over 90% of the subsequent smears resulted in a benign diagnosis. Biopsy outcomes after CS diagnoses of ASCUS-P, ASCUS-R, and ASCUS-C showed SIL in 80%, 53%, and 66% of patients, respectively. For LB diagnoses, subsequent smears detected SIL in 33% of patients with a diagnosis of ASCUS-P, 22% of patients with a diagnosis of ASCUS-R, and 12% of patients with a diagnosis of ASCUS-C. Biopsy outcomes after LB diagnoses of ASCUS-P, ASCUS-R, and ASCUS-C showed SIL in 68%, 64%, and 66% of patients, respectively.

CONCLUSIONS

There appears to be no statistically valid benefit from a clinical point of view in qualifying an ASCUS interpretation by either CS or LB, except for CS evaluation of patients with a diagnosis of ASCUS-P.

Liquid-based cytology for primary cervical cancer screening: a multi-centre study

The aim of this six-centre, split-sample study was to compare ThinPrep fluid-based cytology to the conventional Papanicolaou smear. Six cytopathology laboratories and 35 gynaecologists participated. 5428 patients met the inclusion criteria (age > 18 years old, intact cervix, informed consent). Each cervical sample was used first to prepare a conventional Pap smear, then the sampling device was rinsed into a PreservCyt vial, and a ThinPrep slide was made. Screening of slide pairs was blinded (n = 5428). All non-negative concordant cases (n = 101), all non-concordant cases (n = 206), and a 5% random sample of concordant negative cases (n = 272) underwent review by one independent pathologist then by the panel of 6 investigators. Initial (blinded) screening results for ThinPrep and conventional smears were correlated. Initial diagnoses were correlated with consensus cytological diagnoses. Differences in disease detection were evaluated using McNemar's test. On initial screening, 29% more ASCUS cases and 39% more low-grade squamous intraepithelial lesions (LSIL) and more severe lesions (LSIL+) were detected on the ThinPrep slides than on the conventional smears (P = 0.001), including 50% more LSIL and 18% more high-grade SIL (HSIL). The ASCUS:SIL ratio was lower for the ThinPrep method (115:132 = 0.87:1) than for the conventional smear method (89:94 = 0.95:1). The same trend was observed for the ASCUS/AGUS:LSIL ratio. Independent and consensus review confirmed 145 LSIL+ diagnoses; of these, 18% more had been detected initially on the ThinPrep slides than on the conventional smears (P = 0.041). The ThinPrep Pap Test is more accurate than the conventional Pap test and has the potential to optimize the effectiveness of primary cervical cancer screening.

Liquid-based cervical-cell collection with brushes and wooden spatulas: a comparison of 100 conventional smears from high-risk women to liquid-fixed cytocentrifuge slides, demonstrating a cost-effective, alternative monolayer slide preparation method

Our purpose was to demonstrate that 17.5-mm liquid-based cytocentrifuge circle-slides made using a Hettich (Andreas Hettich Co., Tuttlingen, Germany) cytocentrifuge are at least as efficacious as conventional smears for detecting cervical abnormalities. One hundred conventional smears were collected with cytobrushes and wooden spatulas from high-risk women. Both devices were then placed into CytoRich Red (AutoCyte, Inc., Burlington, NC). Cells were concentrated from CytoRich Red by centrifugation and suspended in CytoRich Yellow. Two 17.5-mm circle-slides were produced, compared to each other in order to test reproducibility of diagnoses between slides, and compared to conventional slides. Sixty-five normals, three ASCUS, three LSIL, and two HSIL matched. Overall, cytocentrifugation yielded 27 additional findings among 25 cases. Also, it downgraded one conventional ASCUS to normal (immature metaplasia and chronic inflammation) and one conventional HSIL to normal (transitional cell metaplasia). Cytocentrifugation of 14 conventional normals afforded four ASCUS and 10 LSIL. Cytocentrifugation of 11 conventional ASCUS afforded nine LSIL and two HSIL (one with AIS). One HSIL + AIS was found with a conventional HSIL. Cytobrushes and wooden spatulas can be used to collect material for liquid-based cervico-vaginal cytology if they are placed into CytoRich Red. Hettich cytocentrifuge slides were more reliable than conventional smears in presenting well-dispersed, sharply imaged cells, affording greater diagnostic sensitivity and certainty. Compared to previous split-sample studies, three different outcomes were noted: 1) the endocervical component was consistently well-represented; 2) AIS was seen more often in liquid-based slides; and 3) the liquid-based slide did not underdiagnose its conventional companion. The liquid-based preparations downgraded one ASCUS to normal and one conventional HSIL to transitional-cell metaplasia. Histology correlation of these two cases agreed with the liquid-based cytology diagnoses, which validates their specificity. These improvements are ascribed to differences in fixation and processing. The low cost, ease of operation, and reusable chambers of the Hettich cytocentrifuge make it a cost-effective liquid-based cytology instrument, especially for small to intermediate-size laboratories. The claims that this paper makes must be proven by additional studies, and test implementation needs to be scrutinized by appropriate regulatory agencies whose standards may vary from country to country. Diagn. Cytopathol. 2000;22:86-91.

Performance of a fluid-based, thin-layer papanicolaou smear method in the clinical setting of an independent laboratory and an outpatient screening population in New England

BACKGROUND

A patented, fluid-based, thin-layer method for preparation of Papanicolaou (Pap) smears (ThinPrep Pap test) has been reported to be significantly more effective than the conventional smear invented by George Papanicolaou. We tested this position by comparing the cytologic diagnosis and specimen adequacy results obtained using the ThinPrep method with data from conventional Pap smears obtained from a similar population.

METHODS

Test results of 56 339 ThinPrep specimens were compared with results from 74 756 conventional smear cases obtained from the same sources in a corresponding period of the previous year.

RESULTS

The use of ThinPrep for cervicovaginal cytology produced a 75.14% increase in the detection of low-grade squamous intraepithelial lesions and higher diagnoses. Detection of low-grade squamous intraepithelial lesions increased by 71.65% (from 1.58% to 2.71%), and detection of high-grade squamous intraepithelial lesions increased by 102.54% (from 0.26% to 0.52%). There was a 39.11% decrease in the atypical squamous cells of undetermined significance-intraepithelial lesion ratio (from 2.07 to 1.26). There were also marked decreases in the number of specimens categorized as "satisfactory but limited," owing to obscuring inflammation (-94.34%), obscuring blood (-99.84%), and poor fixation (-99.25%).

CONCLUSION

ThinPrep produced increased detection of premalignant precursors while improving specimen adequacy.

ThinPrep Pap Test: performance and biopsy follow-up in a university hospital

BACKGROUND

The ThinPrep Pap Test (TP), a liquid-based cervical cytology preparation, was approved for use in the U.S. in 1996. The purpose of this study was to compare TP performance and biopsy follow-up studies with a similar population of high risk patients sampled by conventional Papanicolaou (Pap) smear (CS).

METHODS

Diagnostic and specimen adequacy interpretations for 2727 TP direct-to-vial Pap tests from a high risk university hospital practice were compared with 5000 CS preparations from the same physicians taken 1 year previously. Biopsy follow-up studies for the categories of squamous intraepithelial lesion (SIL), carcinoma, and atypical squamous cells of undetermined significance (ASCUS) for each time period and technique were contrasted.

RESULTS

The SIL/carcinoma detection rate increased from 7.7% to 10.5% (P < 0.01) and the ASCUS rate decreased from 12.5% to 6.9% (P < 0.01); the percentage of satisfactory but limited specimens decreased from 19.4% to 10.5% (P < 0.01). Low grade SIL cases increased by 57% (P < 0.01) whereas the 26% increase in high grade SIL cases was not statistically significant. Greater than 90% of ungraded SIL, high grade SIL, and carcinoma cases had abnormal biopsies by both the TP and CS methods. The number of biopsy-confirmed high grade dysplasias and carcinomas was similar in the two groups. A low grade SIL detected by TP was less likely to have an abnormal biopsy (70% vs. 85% for CS). Nevertheless, the 57% increase in low grade SIL diagnoses by TP resulted in more TP patients with dysplastic biopsy diagnoses. Follow-up studies for ASCUS cases diagnosed by either TP or CS were similar, and 21-24% of patients eventually were found to have dysplasia.

CONCLUSIONS

The TP technique appears to lead to the increased detection of low grade SIL lesions, decreased satisfactory but limited samples, and fewer equivocal specimens. No increase in biopsy-confirmed high grade dysplasias and carcinomas was found. Follow-up studies for the ASCUS category were nearly identical to those for CS.