Use of the Thin Prep Pap Test in clinical practice

Endoscopic ultrasound-guided fine needle aspiration with liquid-based cytology preparation in the diagnosis of metastatic small-cell carcinoma in the pancreas

Pancreatic metastasis is extremely rare, particularly from small-cell lung cancer (SCLC). Studies on the role of endoscopic ultrasound-guided fine needle aspiration (EUS-FNA) with liquid-based cytology (LBC) in the diagnosis of metastatic small-cell carcinoma in the pancreas have been rarely conducted. We report herein a case of pancreatic metastasis from SCLC diagnosed using EUS-FNA with LBC (ThinPrep). A 71-year-old man presented with chief complaints of hemoptysis and jaundice over the past 1 month. Lung & pancreas tumors with multiple liver nodules were detected on computed tomography. The aspirated material from the pancreas using EUS-FNA was prepared as a cytologic specimen with ThinPrep method, which revealed scattered and clustered "small blue cells" with scant cytoplasm and stippled chromatin with frequent apoptotic bodies. Immunocytochemical staining of the cellblock material revealed strong positivity for CD56 and thyroid transcription factor-1. Endobronchial biopsy for lung mass revealed nests of small, round, blue tumor cells with hyperchromatic nuclei showing salt and pepper chromatin, scant cytoplasm, and brisk mitotic activity. Therefore, a diagnosis of metastatic small-cell carcinoma to the pancreas with an extensive stage was finally made.

Comparison of Unsatisfactory Samples from Conventional Smear versus Liquid-Based Cytology in Uterine Cervical Cancer Screening Test

BACKGROUND

Cervical cytology for uterine cervical cancer screening has transitioned from conventional smear (CS) to liquid-based cytology (LBC), which has many advantages. The aim of this study was to compare the proportion of unsatisfactory specimens from CS versus LBC at multiple institutions including general hospitals and commercial laboratories.

METHODS

Each participating institution provided a minimum of 500 Papanicolaou (Pap) test results for analysis. Pap tests were classified according to the participating institution (commercial laboratory or general hospital) and the processing method (CS, ThinPrep, SurePath, or CellPrep). The causes of unsatisfactory results were classified as technical problems, scant cellularity, or complete obscuring factors.

RESULTS

A total of 38,956 Pap test results from eight general hospitals and three commercial laboratories were analyzed. The mean unsatisfactory rate of LBC was significantly lower than that of CS (1.26% and 3.31%, p = .018). In the LBC method, samples from general hospitals had lower unsatisfactory rates than those from commercial laboratories (0.65% vs 2.89%, p = .006). The reasons for unsatisfactory results were heterogeneous in CS. On the other hand, 66.2% of unsatisfactory results in LBC were due to the scant cellularity.

CONCLUSIONS

Unsatisfactory rate of cervical cancer screening test results varies according to the institution and the processing method. LBC has a significantly lower unsatisfactory rate than CS.

Comparison of Unsatisfactory Samples from Conventional Smear versus Liquid-Based Cytology in Uterine Cervical Cancer Screening Test

BACKGROUND

Cervical cytology for uterine cervical cancer screening has transitioned from conventional smear (CS) to liquid-based cytology (LBC), which has many advantages. The aim of this study was to compare the proportion of unsatisfactory specimens from CS versus LBC at multiple institutions including general hospitals and commercial laboratories.

METHODS

Each participating institution provided a minimum of 500 Papanicolaou (Pap) test results for analysis. Pap tests were classified according to the participating institution (commercial laboratory or general hospital) and the processing method (CS, ThinPrep, SurePath, or CellPrep). The causes of unsatisfactory results were classified as technical problems, scant cellularity, or complete obscuring factors.

RESULTS

A total of 38,956 Pap test results from eight general hospitals and three commercial laboratories were analyzed. The mean unsatisfactory rate of LBC was significantly lower than that of CS (1.26% and 3.31%, p = .018). In the LBC method, samples from general hospitals had lower unsatisfactory rates than those from commercial laboratories (0.65% vs 2.89%, p = .006). The reasons for unsatisfactory results were heterogeneous in CS. On the other hand, 66.2% of unsatisfactory results in LBC were due to the scant cellularity.

CONCLUSIONS

Unsatisfactory rate of cervical cancer screening test results varies according to the institution and the processing method. LBC has a significantly lower unsatisfactory rate than CS.

Unsatisfactory rate in liquid-based cervical samples as compared to conventional smears: A study from tertiary care hospital

Background:

Developed countries adopted liquid-based cytology (LBC) cervical cytology, partly because of its lower proportions of unsatisfactory (U/S)/inadequate samples. This study was carried out to evaluate effect on the rate of U/S samples after introduction of LBC in our laboratory.

Materials and Methods:

An audit of U/S cervical samples was performed, which included split samples (n = 1000), only conventional Pap smear (CPS) smears (n = 1000), and only LBC samples (n = 1000). The smears were reviewed by two observers independently, and adequacy for the samples was assessed as per The Bethesda System 2001. The reasons for U/S rate in split samples were categorized into various cytologic and/or technical reasons.

Results:

U/S rate was far less in only LBC samples (1.2%) as compared to only CPS (10.5%) cases. Cases in the satisfactory but limited category were also less in only LBC (0.4%) as compared to only CPS (3.2%) samples. The main reasons for U/S smears in split samples were low cell count (37.2% in CPS; 58.8% in LBC). The second main reason was low cellularity with excess blood and only excess blood in CPS samples.

Conclusion:

There was a significant reduction of U/S rate in LBC samples as compared to CPS samples, and the difference was statistically significant. The main cause of U/S samples in LBC was low cellularity indicating a technical fault in sample collection. The main cause of U/S rate in CPS was low cellularity followed by low cellularity with excess blood. Adequate training of sample takers and cytologists for the precise cell count to determine adequacy in smears can be of great help in reducing U/S rate.

Detection of hTERC and c-MYC genes in cervical epithelial exfoliated cells for cervical cancer screening

Cervical cancer is the principal cause of mortality due to cancer in women worldwide. New predictive markers may increase survival rates by improving the treatment of patients at a high risk for cancer. This study was carried out to investigate the amplification of human telomerase RNA component (hTERC) or/and c-MYC in cervical epithelial exfoliated cells for cervical carcinoma screening. We collected 171 specimens. including speciments from normal cervix, benign lesions, cervical intraepithelial neoplasia (CIN)1, CIN2 and CIN3, or carcinoma in situ, as well as invasive cervical squamous cell carcinoma. Fluorescence in situ hybridization (FISH) was performed to detect alterations in hTERC and c-MYC expression. We analyzed the area under the receiver operating characteristic (ROC) curve (AUC), as well as the sensitivity and specificity of single screening and conjoined screening. There was a trend toward an increasing amplification of 2 genes with the increasing severity of cervical lesions. ROC curve analysis demonstrated that the AUC values of the hTERC gene for the screening of different cervical lesions were >0.8. Compared with the hTERC gene, the AUC of the c-MYC gene for the screening of ≥CIN3 was >0.8 and the AUC for the screening of other cervical lesions was >0.7. For the screening of cervical lesions above the grade of benign lesions, cytological diagnosis was superior to the gene detection with significant differences. For the screening of cervical lesions >CIN1, there were no statistically significant differences (P>0.05) between the hTERC gene and cytological diagnosis, whereas the screening results of c-MYC detection and cytological diagnosis differed significantly (P<0.05). For the screening of cervical lesions >CIN2 or >CIN3, the detection of hTERC and c-MYC genes and cytological diagnosis had similar screening results with no statistically significant differences (P>0.05). In conclusion, using FISH to detect the amplification of hTERC or/and c-MYC on cervical epithelial exfoliated cells may be a useful and specific screening method for precancerous lesions.

Effects of transitioning from conventional methods to liquid-based methods on unsatisfactory Papanicolaou tests: results from a multicenter US study

BACKGROUND

Papanicolaou (Pap) testing has transitioned from conventional preparations (CPs) to liquid-based preparations (LBPs) because of the perceived superiority of LBPs. Many studies conclude that LBPs reduce unsatisfactory Pap tests; however, some believe that the evidence substantiating this claim is weak. The authors studied the effect of the transition from CPs to LBPs on the proportion of unsatisfactory Pap tests in 4 health care systems in the United States participating in the National Institutes of Health-funded Screening Effectiveness and Research in Community-Based Healthcare (SEARCH) project.

METHODS

The study cohort consisted of 548,174 women ages 21 to 65 years who had 1443,725 total Pap tests between 2000 and 2010. Segmented regression analysis was used to estimate the effect of adopting LBPs on the proportion of unsatisfactory Pap tests after adjusting for age.

RESULTS

Three sites that implemented SurePath LBP experienced significant reductions in unsatisfactory Pap tests (estimated effect: site 1, -2.46%; 95% confidence interval [CI], -1.47%, -3.45%; site 2, -1.78%; 95% CI, -1.54%, -2.02%; site 3, -8.25%; 95% CI, -7.33%, -9.17%). The fourth site that implemented ThinPrep LBP did not experience a reduction in unsatisfactory Pap tests. The relative risk of an unsatisfactory Pap test in women aged ≥ 50 years increased after the transition to LBPs (SurePath: relative risk, 2.1; 95% CI, 1.9-2.2; ThinPrep: relative risk, 1.7; 95% CI, 1.5-2.0).

CONCLUSIONS

The observed changes in the proportion of unsatisfactory Pap tests varied across the participating sites and depended on the type of LBP technology, the age of women, and the rates before the implementation of this technology.

Accuracy of several cervical screening strategies for early detection of cervical cancer: a meta-analysis

OBJECTIVE

The objectives of this study were to assess the accuracy of 6 common cervical screening strategies, including visual inspection with acetic acid, with a magnifying device, or with Lugol iodine (VILI), human papillomavirus testing with Hybrid Capture 2 assay, conventional Papanicolaou smear, and thin liquid-based cytology (LBC), and then to compare data obtained by the aforementioned 6 strategies.

METHODS

PubMed, EMBASE, and The Cochrane Library were systematically searched for all original relevant studies about early detection of cervical cancer. A meta-analysis was performed to evaluate the accuracy of the 6 screening strategies covering sensitivity, specificity, diagnostic odds ratio, and the area under the receiver operating characteristic curve.

RESULTS

Fifteen articles containing 22 cross-sectional studies were finally identified. The combined estimates of sensitivity for visual inspection with acetic acid, magnified visual inspection with acetic acid, VILI, Hybrid Capture 2 assay, conventional Papanicolaou smear, and LBC were 77%, 64%, 91%, 74%, 59%, and 88%, respectively; the combined values of specificity of these screening strategies were 87%, 86%, 85%, 92%, 94%, and 88%, respectively; the diagnostic odds ratio were 22.43, 10.30, 57.44, 33.26, 22.49, and 51.56, respectively; and the area under the receiver operating characteristic curve were 0.8918, 0.7737, 0.9365, 0.9486, 0.9079, and 0.9418, respectively.

CONCLUSIONS

This meta-analysis suggests that LBC appeared to be promising in primary cervical cancer screening in resourced regions, and VILI might be a good choice to identify/exclude cervical cancerous and precancerous lesions in resource-constrained regions.

Causes and Relevance of Unsatisfactory and Satisfactory but Limited Smears of Liquid-Based Compared With Conventional Cervical Cytology

Context.—Recent randomized controlled trials have shown a significant decrease in unsatisfactory rates for liquid-based cytology (LBC) compared with conventional Papanicolaou test (CP). The underlying causes and relevance of unsatisfactory results for LBC and CP have never been compared within the setting of a randomized controlled trial.

Objective.—To examine differences in causes and relevance of unsatisfactory and satisfactory but limited by (SBLB) results for LBC and CP.

Design.—Data from the Netherlands ThinPrep Versus Conventional Cytology (NETHCON) trial were used, involving 89 784 women. Causes and relevance of unsatisfactory and SBLB results were analyzed.

Results.—The primary cause for unsatisfactory results for CP and LBC was scant cellularity. Other causes for unsatisfactory CPs were virtually eliminated with LBC. The same was true for SBLB subcategories, with the exception of SBLB absence of transformation zone component and SBLB scant cellularity. The SBLB absence of transformation zone component showed a statistically significant 22% and SBLB scant cellularity a 12% nonsignificant increase with LBC. The detection rates of abnormalities found during 18 months of follow-up of unsatisfactory test results did not differ significantly between the 2 study arms, nor did they differ from the initial test positivity rates from the NETHCON trial.

Conclusions.—Liquid-based cytology shows an almost complete elimination of most causes for unsatisfactory CP, with scant cellularity remaining as the sole cause for unsatisfactory LBC. On the other hand, with LBC a significant increase of smears without a transformation zone component was noted. Women with an unsatisfactory test result are not at increased risk for cervical abnormalities either with LBC or with CP.

Trial Registration.—Nederlands Trial Register, NTR1032, www.trialregister.nl.

Glacial acetic acid treatment and atypical endocervical glandular cells: an analysis of 92 cases

Glacial acetic acid (GAA) treatment minimizes the risk that bloody ThinPrep (Hologic, Marlborough, MA) Papanicolaou (Pap) test samples will be unsatisfactory for diagnosis. In our experience, GAA treatment also adversely affects the morphologic appearance of endocervical glandular cells. We analyzed a series of 92 consecutive GAA-treated Pap tests interpreted as atypical endocervical cells (AECs) and compared these with a control group of 130 samples with AECs in Pap tests that had not been treated with GAA to determine if GAA treatment increases the false-positive diagnosis of AECs. By using search data, the rates of AEC interpretations in the GAA-treated and GAA-untreated samples were calculated. Follow-up data, including human papillomavirus results and follow-up cytology and surgical pathology results, were collected. The GAA group had significantly fewer lesions on follow-up surgical pathology examinations than did the control group (6/69 [9%] vs 28/110 [25.5%]; P < or = .01). In our experience, GAA treatment increases the false-positive diagnosis of AECs.

Liqui-Prep® versus conventional Papanicolaou smear to detect cervical cells abnormality by split-sample technique: a randomized double-blind controlled trial

To assess the diagnostic performances of LiquiPrep® (LP) to detect cervical cellular abnormality in comparison to Papanicolaou (Pap) smear in 194 women with abnormal cervical cytology who were scheduled for colposcopy at the institution between January 2008 and November 2008. The women were randomized to undergo a repeated cervical cytologic evaluation by Pap smear followed by LP, or the two methods in alternating order. The pathologist was blinded to previous cytologic diagnosis and the pair of slides assigned for each woman. Cytologic results from each method were compared to subsequent histopathology. Mean screening time for each LP and Pap slides were 4.3 ± 1.2 minutes and 5.4 ± 1.1 minutes, respectively (P < 0.001). From 194 cases, ASC or AGC were diagnosed in 72 cases (37.1%) from LP and 68 cases (35.1%) from Pap smear. After excluding the ASC/AGC group, the overall cytologic diagnostic agreement between the two tests were 69 of 87 cases (73.6%) while the agreements with histologic diagnoses were 39/87 cases from LP (44.8%) and 41 (47.1%) from Pap smear (P = 0.824). The accuracy of LP was not significantly different from Pap test, 43.4% (95% confidence interval [CI]: 34.8-52.1%) compared to 44.4% (95% CI: 35.7-53.1%). LP did not have superior performance over Pap test to detect high-grade lesions (≥ cervical intraepithelial neoplasia II) using ASC/AGC as the threshold with the sensitivity of 70.5% (95% CI: 64.0-76.9%) versus 77.3% (95% CI: 71.4-83.2%), respectively.

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.

ThinPrep are superior to conventional smears in the cytological diagnosis of subfertile men by testicular fine-needle aspiration

The aim of this study was the comparison of liquid-based cytology (ThinPrep, TS) to conventional smears (CS) in the investigation of subfertile men with testicular fine-needle aspiration (FNA). Between January and December 2004, testicular FNA biopsies were performed in 30 subfertile men. Both TS and CS were diagnosed according to Meng classification. Features specifically recorded in each smear included sample adequacy, tissue cells preservation, contamination with red blood cells, quality of smear background, ease of cell recognition, and the cytological diagnosis. There was agreement in the cytological diagnosis between TS and CS (P = 0.88) and sample adequacy (P = 0.73). TS was superior to CS regarding cell preservation, presence of red blood cells or tissue artifacts, quality of the smear background, and cell recognition (P < 0.0001). In testicular FNA cytology, TS appear to be superior to CS in respect to cell preservation, absence of red blood cells, background quality, and cell recognition. These advantages, however, are not translated in improved cytological diagnosis.

Comparative study of the ThinPrep Pap test and conventional cytology results in a Canadian cohort

OBJECTIVE

To compare the frequency of Pap test results in a prospective series of direct to vial ThinPrep tests to a cohort of conventionally prepared tests. To follow-up all test results for a minimum of 2 years and assess performance based on this outcome.

METHODS

All women presenting for either routine screening or colposcopic examination in 2001 were enrolled in the ThinPrep cohort. A similar, population of conventionally prepared tests was extracted from the year 2000 laboratory data. Information on all concurrent and follow-up cervical specimens over the ensuing 2 years was retrieved.

RESULTS

The ThinPrep cohort comprised 2288 Pap tests and the conventional, 2211. The frequency of normal [within normal limits (WNL) and benign cellular changes (BCC)] results in the ThinPrep cohort was 6% lower and the frequency of abnormal [> or =atypical squamous cells of undetermined significance (ASCUS)] results was 6.8% higher. Respective ThinPrep and conventional cohort results were 1156 (51%) and 1291 (58%) WNL, 625 (27%) and 561 (25%) BCC, 101 (4%) and 65 (3%) ASCUS, 21 (1%) and 2 (0.1%) atypical glandular cells of undetermined significance, 301 (13%) and 224 (10%) low-grade squamous intraepithelial lesion (LSIL), and 74 (3%) and 40 (2%) high-grade SIL (HSIL) (P < 0.0001). Follow-up was available for nearly 80% of each cohort. LSIL or higher was confirmed in 57.5% (n = 266) of the abnormal ThinPrep and 60.9% (n = 190) of the abnormal conventional tests. The ThinPrep yield of confirmed tests however was almost 50% higher than the conventional test.

CONCLUSION

In this population, ThinPrep was superior to the conventional Pap test.

Human Papillomavirus Testing and Liquid-Based Cytology: Results at Recruitment From the New Technologies for Cervical Cancer Randomized Controlled Trial

BACKGROUND

Although testing for human papillomavirus (HPV) has higher sensitivity and lower specificity than cytology alone for detecting cervical intraepithelial neoplasia (CIN), studies comparing conventional and liquid-based cytology have had conflicting results.

METHODS

In the first phase of a two-phase multicenter randomized controlled trial, women aged 35-60 years in the conventional arm (n = 16,658) were screened using conventional cytology, and women in the experimental arm (n = 16,706) had liquid-based cytology and were tested for high-risk HPV types using the Hybrid Capture 2 assay. Women in the conventional arm were referred to colposcopy with atypical cells of undetermined significance (ASCUS) or higher and those in the experimental arm were referred with ASCUS or higher cytology or with a positive (> or = 1 pg/mL) HPV test. Sensitivity and positive predictive value (PPV) for detection of cervical intraepithelial neoplasia grade 2 or higher (CIN2+) were calculated.

RESULTS

The screening methods and referral criterion applied in the experimental arm had higher sensitivity than that in the conventional arm (relative sensitivity = 1.47; 95% confidence interval [CI] = 1.03 to 2.09) but a lower PPV (relative PPV = 0.40; 95% CI = 0.23 to 0.66). With HPV testing alone at > or = 1 pg/mL and at > or = 2 pg/mL, the gain in sensitivity compared with the conventional arm remained similar (relative sensitivity = 1.43, 95% CI = 1.00 to 2.04 and relative sensitivity = 1.41, 95% CI = 0.98 to 2.01, respectively) but PPV progressively improved (relative PPV = 0.58, 95% CI = 0.33 to 0.98 and relative PPV = 0.75, 95% CI = 0.45 and 1.27, respectively). Referral based on liquid-based cytology alone did not increase sensitivity compared with conventional cytology (relative sensitivity = 1.06; 95% CI = 0.72 to 1.55) but reduced PPV (relative PPV = 0.57; 95% CI = 0.39 to 0.82).

CONCLUSIONS

HPV testing alone was more sensitive than conventional cytology among women 35-60 years old. Adding liquid-based cytology improved sensitivity only marginally but increased false-positives. HPV testing using Hybrid Capture 2 with a 2 pg/mL cutoff may be more appropriate than a 1 pg/mL cutoff for primary cervical cancer screening.

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 specimen order on Chlamydia trachomatis and Neisseria gonorrhoeae test performance and adequacy of Papanicolaou smear

STUDY OBJECTIVE

To evaluate the effect of specimen collection order on the performance of diagnostic tests for Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC), and the specimen adequacy of ThinPrep Papanicolaou (Pap) smears.

DESIGN

Prospective cohort study.

SETTING

Public adolescent clinic.

POPULATION

313 women.

INTERVENTIONS

The order of five cervical testing specimens was randomized for (1) ligase chain reaction (LCR) and (2) polymerase chain reaction (PCR) for both CT and GC; (3) transcription-mediated amplification (TMA) for CT; (4) culture for CT; and (5) cytology and LCR for GC and CT performed on ThinPrep Pap specimens. For CT and GC, a reference standard was based on three different tests performed on separate specimens. Generalized estimating equations were used to account for repeated measures.

MAIN OUTCOME MEASURE

Sensitivity and specificity of diagnostic tests.

RESULTS

The proportion of inadequate Pap smears was independent of specimen order. As a group, nucleic acid amplification test (NAAT) sensitivity and specificity for GC and CT were similar in the first two (early) and last three (late) swabs. Although point estimates for sensitivity were higher in the early swabs compared to the late swabs for GC LCR (13% difference), GC PCR (13%), and CT TMA (10%), these differences were not statistically significant. Their clinical significance warrants further investigation.

CONCLUSIONS

In clinical settings where both Pap smears and STI testing are performed in adolescents, clinical considerations can influence the order of specimen collection, since neither Pap specimen adequacy nor test performance of NAAT for CT and GC were significantly associated with swab order.

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.

Improvement of diagnostic accuracy and screening conditions with liquid-based cytology

The aim of this population-based study was to compare the histological follow-up diagnoses of cervicocytological neoplasia (dysplasia, carcinoma in situ and carcinoma) in conventional Papanicolaou (CP) smear and ThinPrep PapTest samples (TP). All cytological samples from the County of Funen, Denmark, in the periods 2000 (n = 34,832) and 2002 (n = 29,995) were included in the study. In 2000 and 2002, the specimens were CP and TP, respectively. The detection rate of > or = mild dysplasia was 0.8% in CP and 1.4% in TP, showing a 75% increase in TP when compared with CP (p < 0.001). Histological follow-up of > or = moderate dysplasia revealed a neoplastic lesion in 77.1% and 87.9% in CP and TP, respectively (P < 0.001). The present study indicates that the diagnostic accuracy of cervical cytology is improved with liquid-based cytology. In addition, we focus on the optimized cellular material that shows the diagnostic details very clearly to the microscopist and leads to radically improved screening conditions.

Significance of atypia in conventional Papanicolaou smears and liquid-based cytology: a follow-up study

The diagnosis of atypical squamous epithelial cells, borderline nuclear changes, is associated with some controversy, as it encompasses benign, reactive, as well as possible neoplastic conditions. The aim of this study was to evaluate the follow-up diagnoses of cytological atypia in conventional Papanicolaou smears (CP) and liquid-based samples by the ThinPrep Pap Test (TP). A total of 1607 CP smears from 1 January 2000 to 31 December 2000 and 798 TP samples from 1 January 2002 to 31 December 2002 diagnosed as atypia were included. The results show that the detection rate of atypia in cervical cytological samples was reduced by 41.3% (P < 0.001) in TP compared with CP. Cytological and histological follow-up data showed the presence of neoplastic lesions in 34.7% of patients screened by TP versus 22.3% of patients screened by CP, corresponding to a 55.6% increase in TP (P < 0.001). Follow-up diagnosis of mild dysplasia was seen more than twice as often in TP than in CP (12.8% versus 5.0%, P < 0.001). The prevalence of moderate and severe dysplasia was significantly increased with 26.7% in TP compared with CP (21.9% versus 17.2%, P < 0.01). In conclusion, the ThinPrep Pap Test yielded a significant decrease in atypia rates compared with the conventional Papanicolaou test. In subsequent follow-up the percentage of neoplastic lesions was significantly increased in the ThinPrep Pap Test samples.

Reprocessing unsatisfactory ThinPrep Papanicolaou test specimens increases sample adequacy and detection of significant cervicovaginal lesions

BACKGROUND

The objective of the current study was to determine the effect of reprocessing bloody ThinPrep (TP) samples using a glacial acetic acid technique on the unsatisfactory rate.

METHODS

During a 12-month study period, all TP gynecologic samples received by the Cytology Laboratory from inpatient, outpatient, and community-based clinics at the University of Texas Southwestern Medical Center and the Parkland Health and Hospital System in Dallas, Texas, were enrolled prospectively into the study. The initial TP slides were evaluated for specimen adequacy based on the 2001 Bethesda System. Any TP sample that contained abnormal cells, by definition, was not considered unsatisfactory. The criteria for reprocessing included scant cellularity in a background of abundant blood. Biopsy correlations for all abnormal cytologic diagnoses were established between TP smears and follow-up biopsies.

RESULTS

During the course of the 1-year study period, a total volume of 57,296 TP samples were evaluated by the study laboratory. Prior to reprocessing, the laboratory unsatisfactory rate was 8.32% (4767 of 57,296 TP samples). After reprocessing those samples that were compromised by blood (2593 of 4767 TP samples), the unsatisfactory rate was reduced to 5.47% (3134 of 57,296 TP samples), with an overall reduction by 34.25% (2.85 of 8.32 TP samples). Of 2593 samples that were reprocessed, 62.98% (1633 of 2593 TP samples) changed from inadequate to adequate for the purposes of evaluation. Of those 1633 adequate samples, 1509 samples (92.41%) were negative for intraepithelial lesion or malignancy, 72 samples (4.40%) were atypical squamous cells of unknown significance, 5 samples (0.31%) were atypical glandular cells of undetermined significance, 36 samples (2.20%) were low-grade squamous intraepithelial lesions, 10 samples (0.61%) were high-grade squamous intraepithelial lesions, and 1 sample (0.06%) was adenocarcinoma.

CONCLUSIONS

The authors conclude that the reprocessing of unsatisfactory ThinPrep cervicovaginal cytology samples decrease the unsatisfactory rate considerably, with an increase in the detection of significant abnormal cervicovaginal lesions.

Cervical biopsy-based comparison of a new liquid-based thin-layer preparation with conventional Pap smears

The objective of this study is to compare the diagnostic efficacy of universal collection medium (UCM) liquid-based cytology (LBC) (Digene Corp., MD) and the conventional Pap smear in a comparative study, using histologic results as the gold standard. This was a cross-sectional study. Conventional Pap smears and UCM LBC specimens, obtained from women in a low socioeconomic outpatient population referred to a tertiary center for gynecologic care, were compared. For the purpose of this study, when cervical specimens were collected for cytology, all women underwent colposcopy and biopsy was done if a cervical abnormality was observed. Cytologic evaluation of UCM LBC and conventional Pap smears were carried out separately, masked to the results of the other method. Agreement beyond chance between the two cytologic methods was ascertained by means of the unweighted kappa statistic. Sensitivity, specificity, and predictive values with 95% confidence intervals were calculated for both methods. McNemar's test was used to determine the level of association between the two cytology procedures. A total of 800 women were evaluated. Assessment of the overall agreement between the two cytologic methods yielded a kappa of 0.777 (P < 0.0001). After adjustment for histologic diagnosis, the computed kappa in each stratum was as follows: normal = 0.733; CIN 1 = 0.631; CIN 2/3 = 0.735; cancer = 0.652. The sensitivity and specificity of UCM LBC for detection of cervical intraepithelial lesions and cancer were 75.3% and 86.4%, respectively, not statistically different from the 81.8% and 85.2% seen with the conventional method. This study demonstrates that the UCM LBC method is as accurate as the conventional Pap smear cytology in detecting cervical intraepithelial lesions and cancer even so the UCM samples were systematically prepared from a second sampling of the cervix.

Usefulness of liquid-based cytology specimens for the immunocytochemical study of p16 expression and human papillomavirus testing

BACKGROUND

In cervical lesions, the overexpression of p16 is reported to be closely associated with high-risk human papillomavirus (HPV) infection. The objective of the current study was to confirm the usefulness of liquid-based cervical specimens for p16 staining as well as tissue sections.

METHODS

A total of 98 patients with cervical lesions were entered into the current study. After the cytologic examination using liquid-based cervical smears, the same slides were immunostained for p16 and were compared with slides of simultaneously obtained, immunohistologically stained tissue sections. Moreover, the status of the HPV infection was examined by polymerase chain reaction using residual cytologic samples.

RESULTS

Using liquid-based Pap smears, 98 cases were diagnosed as atypical squamous cells of undetermined significance (38 cases), low-grade squamous intraepithelial lesion (12 cases), high-grade squamous intraepithelial lesion (HSIL) (33 cases), and invasive carcinoma (15 cases). The concordance rate between the cytologic and histologic diagnoses was found to be higher in high-grade lesions compared with low-grade lesions. Immunohistochemistry revealed that all HSIL and invasive carcinoma cases contained p16-positive cells in the liquid-based Pap smears and diffuse p16 staining was observed in all high-grade lesions with greater than CIN Grade 3 cervical intraepithelial neoplasia except for two adenocarcinoma cases. Of the 98 cases, 60 were found to be positive for high-risk HPV and 55 of these 60 HPV-positive cases were found to be p16 positive on cytologic examination. There were 16 cases that demonstrated marked discrepancies between the cytologic and histologic diagnoses.

CONCLUSIONS

The results of the current study confirmed that the immunohistochemical detection of p16 was more sensitive and specific than HPV status in cervical lesions using a liquid-based method as well as tissue samples, suggesting that p16 should be used as a satisfactory biomarker for the primary screening of cervical cytology.

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.

Liquid-based cervical cytology

BACKGROUND

The objective of the current study was to evaluate the applicability of liquid-based cytology in the Netherlands population screening program for cervical cancer.

METHODS

A special committee performed an evaluation of all the available literature. Two methods were investigated: the AutoCytePrep system (currently known as ShurePath-system; TriPath Imaging, Burlington, NC) and the ThinPrep system (Cytyc, Boxborough, MA) for the detection of squamous epithelial abnormalities. All literature up to May 2000 was evaluated.

RESULTS

For the AutoCytePrep system, there were indications that the detection rate for atypical squamous cells of undetermined significance (ASCUS) or higher had lower sensitivity compared with conventional screening. No definitive statement could be made concerning the value of the AutoCytePrep system for the detection rate of low-grade squamous intraepithelial lesions (LSIL) or higher and high-grade squamous intraepithelial lesions (HSIL) or higher because of conflicting results. For the ThinPrep system, there were indications that the detection rate of ASCUS or higher had a higher detection rate compared with conventional screening, with slightly lower specificity. It is likely that the detection rate of LSIL or higher with the ThinPrep system had greater sensitivity compared with conventional screening with almost unchanged specificity. In addition, it is likely that the detection rate of HSIL or higher with the ThinPrep system had a higher detection rate and greater absolute sensitivity compared with conventional screening with almost unchanged relative and absolute specificity.

CONCLUSIONS

Further research that complies with the standards stated in the current study will be necessary to evaluate the applicability of the AutoCytePrep method. Further evaluation of the costs and benefits of the ThinPrep method should be undertaken to decide definitively whether to implement this method in the Netherlands population screening program.

Atypical glandular cells?an update

The diagnostic category of atypical glandular cells (AGC) in the Bethesda system for the reporting of cervicovaginal cytology has undergone significant modification since its inception in 1988. More than a decade later, this category remains a diagnostic challenge to both clinicians and cytopathologists because of the lack of uniform cytologic criteria, the lack of interobserver agreement in the diagnosis, and the lack of standardized patient management guidelines. This article reviews the current classification of AGC in the Bethesda system, the cytomorphologic features and differential diagnosis, the clinical significance of a diagnosis of AGC, and the clinical management of patients with AGC. This article provides a comprehensive clinicopathologic review of the category of AGC.

ThinPrep versus conventional Papanicolaou smear in the cytologic follow-up of women with equivocal cervical smears

BACKGROUND

The purpose of the current study was to compare the efficacy of liquid-based cytology and conventional smears in the cytologic follow-up of cases with "atypical squamous cells, cannot exclude a high-grade lesion" (ASC-H) or "atypical glandular cells" (AGC).

METHODS

Cytologic follow-up was performed on 214 cases with ASC-H/AGC diagnosis an conventional smears using either ThinPrep (n = 100) or conventional Papanicoloau (Pap) tests (n = 114). Results were then compared with further histologic and/or cytologic follow-up.

RESULTS

Repetition on conventional smears enabled a definite diagnosis (within normal limits [WNL], squamous intraepithelial lesion [SIL] or carcinoma) in 58 cases (50.9%). ASC/AGC was confirmed in 50 cases (43.9%), and 6 of the smears (5.3%) were inadequate. WNL, SIL, or carcinoma was diagnosed in 82 (82.0%) cases by following the patients with ThinPrep cytology, whereas ASC or AGC was confirmed in 18 cases (18.0%). No inadequate specimens were found. A diagnosis of SIL or greater (SIL +) was confirmed histologically in 11 of 11 (100.0%) conventional smears and in 31 of 34 (91.2%) ThinPrep specimens. Of the 87 WNL specimens, 9 (8 conventional smears and 1 ThinPrep specimen) developed a histologically confirmed SIL during further follow-up. Specimen adequacy was significantly better in the ThinPrep specimens compared with conventional smears.

CONCLUSIONS

Because of better specimen adequacy, ThinPrep cervical cytology appears to significantly reduce the occurrence of ASC/AGC compared with conventional Pap smears.

Atypical glandular cells

The 2001 Bethesda System has radically altered the classification of glandular abnormalities. The recognition of the cytologic features of atypical glandular cells on cervicovaginal smears is important because a significant number of patients will be found to have an underlying cancerous or dysplastic lesion of the exocervix, endocervix, or endometrium. The differential diagnosis of AGC on cytology is diverse and accurate classification is necessary because the most appropriate form of follow-up depends on the specific subcategorization of the atypical glandular cells. Because the level of interobserver agreement in the diagnosis of AGC is poor, effective communication between cytopathologists and clinicians is essential to accurately triage these patients. This article should help the cytology practitioner by providing a comprehensive review of the approach to the interpretation, clinical significance, histopathologic correlation, and management of patients who have atypical glandular cells on gynecologic cytology specimens.

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.

Cytohistologic correlation rates between conventional Papanicolaou smears and ThinPrep cervical cytology: a comparison

BACKGROUND

The ThinPrep Papanicolaou (Pap) test, a liquid-based alternative to the long-used conventional Pap smear, received Food and Drug Administration approval in 1996. The current study is a comparison of the accuracy, as assessed by cytohistologic correlation, of conventional versus ThinPrep Pap smears in a hospital setting.

METHODS

A retrospective analysis of all patients who underwent Pap smears (conventional and ThinPrep) and pertinent surgical pathology tissue processed in our department over a 1-year period was undertaken. Tissue diagnoses were grouped into broad general categories to correlate with the Bethesda system. The statistical significance of differences between the two types of Pap test results compared with tissue diagnoses was assessed using a chi-square test with 1 degree of freedom and an alpha value of 0.05.

RESULTS

Of the 65,421 Pap smears interpreted during the study period, histologic correlation was possible in 1544 patients. Of those diagnosed as negative (644 conventional and 245 ThinPrep Smears), low-grade squamous intraepithelial lesion (LGSIL) (116 conventional and 114 ThinPrep smears), and high-grade squamous intraepithelial lesions (HGSIL) (142 conventional and 131 ThinPrep smears), there was no statistically significant difference found between the correlation rates of conventional and ThinPrep Pap smear results. However, review of all cases of invasive cervical carcinoma identified during this time period showed the ThinPrep to be less consistent in predicting the presence of invasive carcinoma compared with the conventional Pap smear.

CONCLUSIONS

Based on cytohistologic correlation evidence, the ThinPrep Pap test may not be more effective in detecting cervical disease, particularly invasive carcinoma, when compared with the conventional Pap smear.

Comparative analysis of conventional Papanicolaou tests and a fluid-based thin-layer method

CONTEXT

A fluid-based, direct-to-vial method of thin-layer gynecologic cytology (ThinPrep Pap Test) is reported to be more effective than the conventional Papanicolaou test in the detection of squamous intraepithelial lesions.

OBJECTIVE

This retrospective analysis evaluated the validity of the findings on the thin-layer method using case material at a large independent laboratory and represented a comparison of performance of both methods over an identical period.

METHODS

Data for conventional and ThinPrep tests were compared for 2 periods. Period 1 included 1,421,080 conventional and 56,835 ThinPrep specimens, and period 2 included 564,270 conventional and 109,784 ThinPrep specimens. Squamous intraepithelial lesions were used to determine detection of disease. These 2 sets of data were also analyzed to eliminate effects of any selection bias toward ThinPrep for high-risk patients.

RESULTS

Use of ThinPrep showed a greater than 100% increase in the detection rate of squamous intraepithelial lesions (1.3%-3.4% in period 1 and 1.3%-2.9% in period 2), which was statistically significant after correcting for selection bias. We also found a significant decrease in the false-negative proportion (57% in period 1 and 35% in period 2). There was a marked improvement (233%) in the detection of high-grade squamous intraepithelial lesions in high-risk cases and a decrease in the atypical squamous cells of undetermined significance to squamous intraepithelial lesion ratio from 3.1 to 1.5 in period 2.

CONCLUSION

ThinPrep is better than the conventional Papanicolaou test in detecting squamous intraepithelial lesions and is a superior screening test in detection of precancerous changes of the cervix.

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.

Cell block findings from residual PreservCyt samples in unsatisfactory ThinPrep Paps: no additional benefit

Our objective was to determine whether cell blocks (CB) performed on unsatisfactory ThinPrep Pap Test residual samples rendered additional clinically significant pathologic findings not detected in the original ThinPrep Pap smears. One hundred consecutive ThinPrep Paps categorized as unsatisfactory were selected for this study. The cytologic diagnosis of unsatisfactory was based on lack of cellularity (squamous) or complete obscuring blood or inflammation. Residual PreservCyt samples from these consecutive unsatisfactory ThinPrepPaps were used to prepare a cell block, using the inverted filter technique. One hematoxylin-eosin (H&E)-stained slide was prepared and evaluated. The amount and the cellular changes were noted for all smear constituents and compared with the original slides. The average patient age was 32 +/- 11 yr. The ThinPrepPap was performed as a follow-up on a previous abnormal smear (12%), pregnancy (25%), abnormal bleeding (22%), or previous unsatisfactory ThinPrepPap (5%), or as routine screening (36%). Variable amounts of endocervical cells, endometrial cells, and metaplastic cells, as well as a variable number of squamous epithelial cells, were present in 89%, 9%, 50%, and 35% in the CB method vs. ThinPrep, respectively. Abnormal cellular changes were noted in 15% of patients (9% with LSIL, and 6% with atypia of undetermined significance); 9 patients with squamous dysplasia had a previous abnormal ThinPrep Pap. A follow-up Pap smear and/or cervical biopsy were performed in 10 of the 15 patients with abnormal cytology detected on CB method revealing: LSIL (1 patient), HSIL (1 patient), ASCUS (1 patient), and within normal limits (7 patients). The findings indicate that the preparation of a CB does not contribute significantly. Importantly, no carcinomas or HSILs were identified on CB preparations. Since a large majority of lesions identified were LSILs, a repeat Pap smear in these cases represented a more cost-effective strategy than cell block preparation, although a cell block preparation may be useful in selected cases.

Conventional and liquid-based cervicovaginal cytology: a comparison study with clinical and histologic follow-up

Increased rates of squamous intraepithelial lesion (SIL) diagnosis with liquid-based cervicovaginal cytology (CVC) methods are well documented. This retrospective study compares the ability of the ThinPrep Pap Test (TP) and the conventional Pap smear (CP) to detect biopsy-proven SIL and to exclude nonneoplastic disease. All CVC reports from January 1999 through December 2000 from seven community Family Medicine clinics affiliated with the University of Nebraska were reviewed. For women with at least one CVC diagnosis of epithelial cell abnormality (ECA), follow-up histology, cytology, and clinical data were obtained. Statistical analysis was performed using the chi-square method. SIL was diagnosed in 166 of 3,286 patients by TP (5.1%) and in 169 of 4,872 patients by CP (3.5%) (P < 0.001); 32 of the TP diagnoses (1.0%) and 34 of the CP diagnoses (0.7%) were high-grade SIL (HSIL). Atypical squamous or glandular cells of undetermined significance (ASCUS/AGUS) was the most severe abnormality diagnosed by TP in 218 patients (6.6%) and by CP in 279 patients (5.7%). Follow-up histology data on CVC SIL diagnoses showed evidence of cervical intraepithelial neoplasia in 94 patients screened by TP (2.9%) and in 79 patients screened by CP (1.6%) (P < 0.001); the biopsy diagnoses were CIN 2 or CIN 3 in 34 patients in the TP group (1.0%) and in 28 patients in the CP group (0.6%) (P < 0.025). Follow-up of patients in whom the first ECA CVC diagnosis was ASCUS or AGUS disclosed a positive predictive value for CIN of 22.8% for TP ASCUS/AGUS diagnoses and 11.9% for CP ASCUS/AGUS diagnoses (P < 0.005). In this population, TP was significantly better than CP in detecting biopsy- proven disease and in screening out benign abnormalities.

PreservCyt transport medium used for the ThinPrep Pap test is a suitable medium for detection of Chlamydia trachomatis by the COBAS Amplicor CT/NG test: results of a preliminary study and future implications

The commercial COBAS Amplicor CT/NG test (Roche Diagnostic Systems, Meylan, France) is a sensitive and specific method for detection of Chlamydia trachomatis infections. This test currently consists of using a nucleic acid amplification method to detect C. trachomatis in first-void urine specimens and in endocervical swabs collected in 2-sucrose-phosphate (2SP) transport medium. We conducted a prospective study to determine whether the automated COBAS Amplicor CT/NG test can detect C. trachomatis in cervical specimens collected in PreservCyt transport medium (ThinPrep Pap Test; Cytyc Corporation, Boxborough, Mass.). PreservCyt medium is used to preserve cervical samples before the preparation of ThinPrep slides. We collected 1,000 cervical specimens from young women (age range, 15 to 25 years) during routine Pap smear tests. Only specimens with normal cytology and in which the gynecologist found no clinical evidence of urogenital infections were selected. The samples were stored in PreservCyt transport medium at 15 to 20 degrees C. C. trachomatis was detected in 22 of the 1,000 cervical specimens that had been stored in PreservCyt. To confirm the positive samples, the test was repeated on new endocervical swab specimens collected in 2SP transport medium. Only 9 of the 22 positive patients agreed to undergo this control, but all 9 retested positive. To evaluate the influence of storage conditions on the sensitivity of the C. trachomatis PCR test, all of the positive samples were stored at 15 to 20 degrees C in PreservCyt transport medium and were retested every 2 weeks for 6 weeks. C. trachomatis was successfully amplified from all 22 specimens for the whole 6-week period. The prevalence of C. trachomatis infection was 2.2% in our study population. These results demonstrate that PreservCyt transport medium is a suitable transport medium for detection of C. trachomatis by the COBAS Amplicor CT/NG test. The ThinPrep Pap Test may enable gynecologists to monitor for both cervical lesions and C. trachomatis infections with a single endocervical specimen.

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.

Cytologic features of high-grade squamous intraepithelial lesions involving endocervical glands on ThinPrep cytology

Usage of liquid-based cytology has resulted in better cellular preservation with enhancement of nuclear features. The purpose of this retrospective 2-yr study (January 1999 through December 2000) was to evaluate the cellular features of endocervical gland involvement by a high-grade squamous intraepithelial lesion (HSIL) vs. endocervical adenocarcinoma in situ (AIS) on cell samples processed by the ThinPrep method as compared to conventional smears. Of the 97 cases of CIN III diagnosed on cytology, 52 (54%) showed surface endocervical gland involvement by CIN III and form the basis of this study. There were also six cases of endocervical AIS diagnosed on histology with prior cytology. The architectural features of HSIL involving endocervical glands and AIS were similar to those previously reported on conventional smears. A consistent finding of HSIL involving endocervical glands was the loss of central cell polarity and piling within cell groups, a finding not present in AIS. Central cell polarity was maintained in cellular groupings of AIS. In addition to the cellular feature present on conventional smears, micronucleoli were clearly visualized in cells of HSIL involving endocervical glands and prominent nucleoli were present in AIS. Apoptosis and mitoses were clearly visualized in both entities. Endocervical gland involvement by HSIL has characteristic cell patterns and features on liquid-based/thin-layer cytology that permit their distinction from AIS.

[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.

Utility of additional slides from residual Preservcyt material in difficult ThinPrep gynecologic specimens: a prospective study of 58 cases

ThinPrep purportedly increases the sensitivity of cervicovaginal cytology for detecting abnormal squamous and glandular cells. The value of additional slides from residual Preservcyt material to characterize difficult lesions is unknown. Fifty-eight cases were studied to determine the utility of additional slides for diagnosis and to assess cellular uniformity. In 32 (55%), repeat slides helped make a definitive diagnosis, including 18 atypical squamous cells of uncertain significance (ASCUS) reclassified as low-grade squamous intraepithelial lesion (LGSIL) (13), high-grade squamous intraepithelial lesion (HGSIL) (4), or endometrial adenocarcinoma (1); 5 LGSIL reclassified as HGSIL; 3 atypical glandular cells of uncertain significance (AGUS) reclassified as LGSIL (1) or HGSIL (2); 2 LGSIL?HGSIL classified as LGSIL; and 4 cases confirmed as LGSIL (2) or HGSIL (2). Results were compared to follow-up clinical information, including subsequent cervicovaginal samples and biopsies. The number of abnormal cells was similar between slides in most cases. We conclude that, while ThinPreps prepared from the same vial have similar numbers of abnormal cells, additional slides can be helpful for diagnosis in select cases.

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.

HPV DNA testing of the residual sample of liquid-based Pap test: utility as a quality assurance monitor

HPV DNA testing of the residual sample volume of liquid-based Pap tests has been recommended as a way to determine the appropriate follow-up for women who have equivocal results in routine clinical screening. A major aspect of quality assurance in the cytopathology laboratory consists of correlation of smear interpretation with biopsy or conization results as mandated by CLIA '88. However, the use of histology as the gold standard suffers from similar problems of subjectivity and sampling as the Pap smear. In this study we explore the potential use of HPV DNA testing of the residual volume from the ThinPrep Pap Test (Cytyc Corporation, Boxborough, Massachusetts) as a substitute gold standard in quality assurance monitoring of a cervical cytology screening program. The residual samples from 397 ThinPrep Pap cases were retrospectively analyzed for high-risk HPV DNA using the Hybrid Capture II technique. Sensitivity (71.8%), specificity (86.5%), predictive value of positive (77.1%) and negative (82.9%) ThinPrep Pap interpretations were calculated on the basis of HPV DNA results for 266 cases classed as either squamous intraepithelial lesion (SIL) or negative. Overall, there was agreement between the two tests in 80.8% of cases (Cohen's kappa =.59). The percentage of HPV DNA-positive cases interpreted as atypical squamous cells of uncertain significance (ASCUS) was 43.7%, and the percentage of negative cases was 17.1%. We believe that this approach is an objective adjunct to the traditional quality assurance protocol, with the added benefit that it includes cases interpreted as negative, as well as abnormal cases that do not come to biopsy.

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.

Usefulness of cervical collection by the exact touch, the saccomanno single sampler, combined with automated primary screening

Automated-primary screening is frequently performed, but conventional smears have to be rescreened on coverslip edges because automated systems do not analyze cells near the coverslip edges because of focusing problems. This disadvantage can be overcome by obtaining conventional samples smeared in the center of the slide, e. g., by the Exact Touch (ET), a single sampler introduced by G. Saccomanno. PAPNET-assisted primary screening was performed on 263 samples collected by ET. The smears were classified as "negative" or as "review." The negative cases were rapidly rescreened but not near the coverslip edges. The review cases were fully reanalayzed by the optic microscope. Ten positive smears were identified among the review cases: 3 smears showed changes due to human papillomavirus, 3 low-grade squamous intraepithelial lesions, and 4 high-grade squamous intraepithelial lesions. The detection of abnormal cells was easy by means of the combined use of ET and PAPNET. The ET-PAPNET technique was very useful in analyzing conventional smears and in reducing the time-consuming process of detecting abnormal cells.

Detection of endometrial adenocarcinoma with the ThinPrep Pap test

The ThinPrep Pap Test (Cytyc Corp., Boxborough, MA) was introduced in the Loyola University Medical Center (LUMC) Cytopathology Laboratory in March 1997. This study presents a 26-month retrospective review of the cervicovaginal specimens on all patients who had a cytologic diagnosis of adenocarcinoma either by conventional (CS) or ThinPrep (TP) methods. From March 1997 through May 1999, 16,139 conventional smears and 29,589 TP Pap tests were sent to the LUMC cytopathology laboratory. The three diagnostic glandular categories included: atypical glandular cells of undetermined significance (AGUS); suspicious for adenocarcinoma, endometrial adenocarcinoma, and adenocarcinoma; not otherwise specified (nos). Cytohistologic correlation was performed on all available cases. Since endometrial adenocarcinoma occurs most frequently in peri- and postmenopausal patients, the percentage of patients over the age of 50 was determined for each method; 4,669 (29%) of the women receiving a CS were age 50 or over and 6,839 (23%) of the women who received the TP Pap test were in this age group. Sixteen endometrial lesions were identified on cytology, one (adenocarcinoma) with the CS method and 15 (six AGUS; suspicious for adenocarcinoma, four endometrial adenocarcinomas, and five adenocarcinomas; nos) with the TP method. The one CS case had biopsy confirmation. Fourteen of the 15 TP cases (93%) were confirmed by biopsy; one (7%) case had no follow-up. The TP Pap test yielded a higher percentage of endometrial adenocarcinomas (0.05%) as compared to CS (0.01%). Traditionally, CS has not been a method for the early detection of endometrial glandular lesions. However, of the patients diagnosed as having an endometrial adenocarcinoma in this study, the TP Pap test contributed to an increase in the detection of these lesions as compared to CS. The age group for the two methods was comparable.

Evaluation of cellular residue in the ThinPrep PreservCyt vial

The ThinPrep Pap Testtrade mark is a fluid-based method used for the collection and preparation of cervicovaginal samples. The collection device(s) is/are rinsed in Cytyc's ThinPrep PreservCyt medium and a thin-layer slide is prepared using the ThinPrep 2000 automated processor. The purpose of this study was to determine the detection rates for cervical lesions utilizing an additional ThinPrep slide. Fifty-four cervical samples processed by the ThinPrep method were reviewed. An additional thin-layer slide was obtained from the cellular residue for each case utilizing a new filter. Case selection criteria included cases with a few equivocal cells, a few diagnostic cells, or several low-grade dysplastic cells seen on the original ThinPrep slide. The original slides and repeat slides were reviewed by two cytopathologists and two cytopathology fellows. Fifty-four patients were included in the study, mean age 35 years (range: 16-76). The original diagnoses included: 17 negative cases, 22 atypical squamous cells of undetermined significance (ASCUS), 10 low-grade squamous intraepithelial lesions (LGSILs), four high-grade squamous intraepithelial lesions (HGSILs), and one case of atypical glandular cells of undetermined significance (AGUS). On the repeat slides the diagnosis remained the same in 42 (77.8%) cases, diagnostic cells were not present in 10 (18.5%) cases, fungal elements consistent with candida were detected on the repeat smear in one case (1.8%), and higher grade dysplastic cells were found in two cases (3.7%). Our study showed that the ThinPrep method provides a representative, diagnostic sample on the slide. Repeat processing adds little to the overall diagnosis.

New technologies in cervical cancer precursor detection

The current literature reflects three routes toward improving cervical cancer screening. The first is to improve the test qualities of cytology-based screening. The use of liquid-based cytology and computerized analysis of Papanicolaou tests are examples of attempts at this approach. Secondly, through various combinations of parallel or sequential tests, either the sensitivity or the specificity of a given test could be improved depending on the tests chosen and the order in which they were performed (eg, Papanicolaou test followed by human papillomavirus [HPV] or vice versa). Several excellent studies have been published this year on the use of HPV DNA testing as a primary screening modality and as an adjunct to the triage of mildly abnormal cytologic findings. The recent literature also reflects increasing interest in visual inspection of the cervix and self-collected samples for HPV testing as an equally effective and viable alternative to cytology in low-resource settings. A third possibility is to make use of advances in digital and spectroscopic techniques. In these cost-conscious times, a significant number of articles address the cost-effectiveness of these technologies and the real value of cervical cancer screening. This article reviews the current literature concerning both the advent of new cervical cancer screening technologies and the rediscovery of old ones.