Comparing the accuracy of ThinPrep Pap tests and conventional Papanicolaou smears on the basis of the histologic diagnosis: a clinical study of women with cervical abnormalities

A Comparison of Conventional Pap Smear and Liquid-Based Cytology for Cervical Cancer Screening

Objectives

Early diagnosis and treatment of preinvasive lesions have made cervical cytology one of the most effective methods of cancer screening in industrialized nations, which have seen a sharp decline in the incidence and death of invasive cancer. The aim of this study is to compare liquid-based cytology (LBC) and conventional Pap on cervical smears.

Materials and Methods

From July 2018 to June 2022, 600 patients were included in this cross-sectional study, which was done at the Pathology Department of a Tertiary Care Facility in Western Maharashtra.

Results

Of the 600 patients, 570 (95%) had good conventional Pap smear (CPS), whereas 30 (5%) had poor ones. Five hundred and ninety-two (98.6%) LBC smears were satisfactory, whereas 8 (1.4%) were unsatisfactory. Endocervical cells were seen in 294 (49%) CPS, whereas 360 (60%) LBC smears showed endocervical cells. The morphology of inflammatory cells was similar in both techniques. Hemorrhagic background was seen in 212 (35%) CPS and 76 (12.6%) LBC smears. Only two samples showed diathetic background, which was seen on both CPS and smear. Out of the satisfactory smears in the case of CPS, 512 (85%) cases were reported as negative for intraepithelial lesion or malignancy (NILM), whereas 58 (9.7%) cases were reported as epithelial cell abnormality. In LBC smears, 526 (87.3%) were reported as NILM, whereas 66 (11%) were reported as epithelial cell abnormality. Organisms were detected in 208 (34%) CPS and 162 (27%) LBC smears. Screening time was 5 ± 1 min for CPS, whereas it was 3 ± 1 min for LBC smear.

Conclusion

Mortality will be decreased using LBC on a bigger scale in nations where many smears can be made and screened in a short amount of time, with the provision of doing human papillomavirus-based testing on the remaining sample.

Evaluation of cellular adequacy in endometrial liquid-based cytology

OBJECTIVE

This study evaluated cellular adequacy in endometrial liquid-based cytology (LBC) specimens.

METHODS

In total, 1267 cases were obtained and the rate of unsatisfactory specimen and diagnostic accuracy for malignancy were assessed. If ≥10 cellular clusters composed of ≤30 endometrial cells were found per specimen, then the sample was provisionally considered adequate.

RESULTS

The unsatisfactory rate (with fewer than 10 clusters) was 15.4%. Diagnostic accuracy in specimens with ≥10 clusters was significantly higher (90.5% vs 36.4%) than that in specimens with fewer than10 clusters. Moreover, the unsatisfactory rate in patients aged ≥60 years was significantly higher (33.8% vs 13.2%) than that in patients younger than 60 years. Although the unsatisfactory rate was decreased, significant differences were not found between cases with fewer than five clusters (22.6%) and fewer than 10 clusters (33.8%) in patients aged ≥60 years. Diagnostic accuracy in cases with five or more clusters was significantly higher (90.3% vs 0%) than that in cases with fewer than five clusters.

CONCLUSIONS

We propose that ≥10 clusters with ≥30 endometrial cells per cluster could be used as a specimen adequacy criterion for endometrial LBC. If ≥10 clusters cannot be found in patients aged ≥60 years, then the use of the alternative criterion of five or more clusters may yield satisfactory specimen adequacy.

Comparison of Efficacy in Abnormal Cervical Cell Detection between Liquid-based Cytology and Conventional Cytology

This study was conducted to 1206 women who had cervical cancer screening at Chonburi Cancer Hospital. The spilt-sample study aimed to compare the efficacy of abnormal cervical cells detection between liquid-based cytology (LBC) and conventional cytology (CC). The collection of cervical cells was performed by broom and directly smeared on a glass slide for CC then the rest of specimen was prepared for LBC. All slides were evaluated and classified by The Bethesda System. The results of the two cytological tests were compared to the gold standard. The LBC smear significantly decreased inflammatory cell and thick smear on slides. These two techniques were not difference in detection rate of abnormal cytology and had high cytological diagnostic agreement of 95.7%. The histologic diagnosis of cervical tissue was used as the gold standard in 103 cases. Sensitivity, specificity, positive predictive value, negative predictive value, false positive, false negative and accuracy of LBC at ASC-US cut off were 81.4, 75.0, 70.0, 84.9, 25.0, 18.6 and 77.7%, respectively. CC had higher false positive and false negative than LBC. LBC had shown higher sensitivity, specificity, PPV, NPV and accuracy than CC but no statistical significance. In conclusion, LBC method can improve specimen quality, more sensitive, specific and accurate at ASC-US cut off and as effective as CC in detecting cervical epithelial cell abnormalities.

A comparative analysis of conventional and SurePath liquid-based cervicovaginal cytology: A study of 140 cases

Background:

The role of Papanicolaou (Pap) test in cervical cancer screening need not be overemphasized. While most Western countries have adopted the liquid-based cytology (LBC), which is considered superior, many developing countries are still using the conventional Pap smear (CPS) technique.

Objective:

To compare the staining and cytomorphological features on conventional versus liquid-based cervicovaginal smears.

Materials and Methods:

One hundred and forty cervicovaginal smears prepared by the standard conventional and LBC techniques were interpreted as per the Bethesda system of reporting cervicovaginal smears. Twelve parameters were studied, compared, and statistically analyzed. A P value <0.05 was considered to be statistically significant.

Results:

129/140 (92%) of CPSs and 130/140 (93%) LBC smears were satisfactory. LBC had a significantly shorter screening time (2.0 ± 0.08 vs 4.0 ± 0.65) and better representative material than that of CPS (50% vs 42%). Neutrophils were significantly more in CPS than LBC (96% vs 92%) with a P value <0.05 while hemorrhagic background and red blood cells (RBCs) were more prominent in CPS. LBC showed significant artifactual changes in squamous epithelial cells. Epithelial abnormalities ranging from atypical squamous cells of undetermined significance (ASCUS) to high grade squamous intraepithelial lesion (HSIL) were seen in 3% (4) and 2% (2) of CPSs and LBCs, respectively. Organisms were better picked up in CPS (99% in CPS vs 73% LBC) with a value of P = 0.0001.

Conclusion:

Although a shorter screening time and cleaner background are the major advantages of LBC, CPS is not inferior to LBC. Considering the high cost, rather than the advantages associated with LBC, we feel that CPS is a better option for developing countries.

Manual liquid based cytology in primary screening for cervical cancer--a cost effective preposition for scarce resource settings

Conventional pap smear (CPS) examination has been the mainstay for early detection of cervical cancer. However, its widespread use has not been possible due to the inherent limitations, like presence of obscuring blood and inflammation, reducing its sensitivity considerably. Automated methods in use in developed countries may not be affordable in the developing countries due to paucity of resources. On the other hand, manual liquid based cytology (MLBC) is a technique that is cost effective and improves detection of precursor lesions and specimen adequacy. Therefore the aim of the study was to compare the utility of MLBC with that of CPS in cervical cancer screening. A prospective study of 100 cases through MLBC and CPS was conducted from October 2009 to July 2010, in a Medical College in India, by two independent pathologists and correlated with histopathology (22 cases). Morphological features as seen through MLBC and CPS were compared. Subsequently, all the cases were grouped based on cytological diagnosis according to two methods into 10 groups and a subjective comparison was made. In order to compare the validity of MLBC with CPS in case of major diagnoses, sensitivity and specificity of the two methods were estimated considering histological examination as the gold standard. Increased detection rate with MLBC was 150%. The concordance rate by LBC/histopathology v/s CPS/histopathology was also improved (86% vs 77%) The percentage agreement by the two methods was 68%. MLBC was more sensitive in diagnosis of LSIL and more specific in the diagnosis of inflammation. Thus, MLBC was found to be better than CPS in diagnosis of precursor lesions. It provided better morphology with increased detection of abnormalities and preservation of specimen for cell block and ancillary studies like immunocytochemistry and HPV detection. Therefore, it can be used as alternative strategy for cervical cancer prevention in limited resource settings.

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.

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.

The comparative diagnostic accuracy of conventional and liquid-based cytology in a colposcopic setting

OBJECTIVE

This study was conducted to compare the performance of liquid-based cytology (LBC) and conventional cytology (CS) in the high prevalence setting of colposcopy clinic.

DESIGN

A split sample of matched ThinPrep (TP) and conventional smear from 563 patients were evaluated blindly. The performance of both techniques was compared with the gold standard of biopsy results or normal colposcopy examination in 441 cases.

SETTING

Colposcopy clinic of an inner city hospital for women and children.

SAMPLE

Five hundred and sixty-three women referred to colposcopy clinic over 14-month period.

METHODS

Cervical smears were taken from 563 women referred for colposcopy. Using the split-sample technique, the material was spread on a conventional (CS) slide and the remaining material rinsed in a PreservCyt solution. A T2000 processor was used to prepare LBC preparations. All women underwent colposcopy/biopsy according to local protocol. Four hundred and forty-one women met the diagnostic standard criteria of the study, which was either a normal colposcopy or histopathology result. Sensitivity, specificity and positive and negative predictive values were calculated for both methods of cytology preparations.

MAIN OUTCOME MEASURES

Matched TP and conventional smears, detection of abnormality, matched biopsies, sensitivity, specificity, and positive and negative predictive values.

RESULTS

Inadequate rates for CS and LBC (TP) were 4.3% and 0.68%, respectively. In 73% of cases, the CS and the LBC preparations showed exact agreement, whereas 77% agreement was seen when comparison was made for amalgamated low grade and high grade abnormalities. Low grade cytological abnormalities accounted for 44% of LBC slides versus 37% in CS slides. High grade cytological abnormalities accounted for 22% of LBC versus 17% seen in CS cases (P < 0.001). LBC showed increased sensitivity in the detection of CIN2 or worse than CS (92% and 83%, respectively) and CS showed greater specificity than LBC (82% and 76%, respectively).

CONCLUSIONS

In high prevalence setting, LBC performed at least as well as CS. The inadequate rate was significantly lower with LBC. The numbers are too small, however, to make confident comments about increased sensitivity and negative predictive value with LBC. Larger studies are required to verify these findings.

A cost-effectiveness analysis of four management strategies in the determination and follow-up of atypical squamous cells of undetermined significance

Atypical squamous cells of undetermined significance (ASC-US) are the most common abnormal cytological result on Papanicolaou (Pap) smear. We analyzed four management strategies in a hypothetical cohort of women divided by age group: (1) immediate colposcopy, (2) repeat cytology after an ASC-US Pap smear result, (3) conventional Pap with reflex human papillomavirus (HPV) testing, and (4) liquid-based cytology with reflex HPV testing. Parameter variables were collected from previously published data. Strategies that included reflex HPV testing had the lowest overall costs for all age groups combined. Repeat Pap smears had the highest number of true positive results throughout all stages but also had the uppermost number of missed cancers and highest costs. Immediate colposcopy had the second highest overall costs and detected fewer true positive results than liquid-based cytology. Younger women (aged 18-24 yr) consistently had higher total costs for all strategies investigated. Using the incremental cost-effectiveness (CE) ratio, the immediate colposcopy strategy was more costly and less effective than liquid-based cytology and, therefore, was dominated. The incremental CE ratio was lowest for liquid-based cytology compared with conventional cytology and liquid-based cytology with reflex HPV testing was the most cost-effective strategy.

Cost-effectiveness of liquid-based cytology with or without hybrid-capture II HPV test compared with conventional Pap smears: A study by the French society of clinical cytology

Many articles concerning conventional Pap smears, ThinPrep liquid-based cytology (LBC) and Hybrid-Capture II HPV test (HC II) have been published. This study, carried out by the French Society of Clinical Cytology, may be conspicuous for several reasons: it was financially independent; it compared the efficiency of the conventional Pap smear and LBC, of the conventional Pap smear and HC II, and included an economic study based on real costs; for all the women, a "gold standard" reference method, colposcopy, was available and biopsies were performed whenever a lesion was detected; The conventional Pap smear, the LBC (split-sample technique), the colposcopy, and the biopsies were done at the same time. This study included 2,585 women shared into two groups: a group A of a high-risk population, a group B of a screening population. The statistical analysis of the results showed that conventional Pap smears consistently had superior or equivalent sensitivity and specificity than LBC for the lesions at threshold CIN-I (Cervical Intraepithelial Neoplasia) or CIN-II or higher. It underlined the low specificity of the HC II. Finally, the LBC mean cost was never covered by the Social Security tariff.

Comparison of Performance of Conventional and ThinPrep Gynecologic Preparations in the College of American Pathologists Gynecologic Cytology Program

Context.—Results of clinical trials suggest that interpretation of liquid-based cytology preparations is more accurate and is associated with less screening error than interpretation of conventional preparations.

Objective.—In this study, the performance of participants in interpreting ThinPrep (TP) preparations was compared with participants' performance on conventional Papanicolaou tests in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology (PAP).

Design.—The results of the PAP from the year 2002 were reviewed, and the discordancies to series and exact-match error rates for the 2 cytologic methods were compared.

Results.—For this study, a total of 89 815 interpretations from conventional smears and 20 886 interpretations from TP samples were analyzed. Overall, interpretations of TP preparations had both significantly fewer false-positive (1.6%) and false-negative (1.3%) rates than those of conventional smears (P = .001 and P = .02, respectively) for validated or validated-equivalent slides, as assessed by concordance with the correct diagnostic series. In this assessment of concordance to series, interpretations of educational TP and conventional preparations were similar, except for high-grade squamous intraepithelial lesion, in which the performance was significantly worse for educational TP preparations (false-negative rate of 8.1% vs 4.1% for conventional smears, P &lt; .001). When interpretations were matched to the exact diagnosis, validated-equivalent TP preparations were generally more accurate for diagnoses in the 100 series and 200 series than were conventional smears. Notably, for the reference diagnosis of squamous cell carcinoma, the exact-match error rate on validated equivalent TP slides was significantly greater than that of conventional slides (44.5% vs 23.1%, P &lt; .001). Interpretations of educational TP preparations also had a significantly higher error rate in matching to the exact reference diagnosis for squamous cell carcinoma (33.7% vs 22.8%, P = .007).

Conclusions.—Overall, TP preparations in this program were associated with significantly lower error rates than conventional smears for both validated and educational cases. However, unlike the negative for intraepithelial lesion and malignancy, not otherwise specified, low-grade squamous intraepithelial lesion, and adenocarcinoma cytodiagnostic challenges, participants' responses indicated some difficulty in recognizing high-grade squamous intraepithelial lesion and squamous cell carcinoma.

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.

Liquid-based cytology and conventional cervical smears

BACKGROUND

This study compared the findings of cervical cytology screening by ThinPrep Papanicolaou (Pap) tests (TP) with the findings of screening by conventional cervical smears (CS) in a screening population involving what to the authors' knowledge is the largest sample of ThinPrep Pap tests published to date.

METHOD

Data from 191,581 CS that were screened in the period from March 1, 1998 to February 28, 2000 were compared with data from 190,667 TP performed from March 1, 2000 to February 28, 2002 and that were obtained from the same sources.

RESULTS

With TP, the unsatisfactory rate was reduced from 0.48% to 0.32%. Fewer cases were considered to be suboptimal (19.12% vs. 12.97%). The detection rates of squamous cell carcinomas, adenocarcinomas, and high-grade squamous intraepithelial lesions (HSIL) were essentially unchanged in the TP group (0.005%, 0.003%, and 0.25%, respectively) compared with the rates for the CS group (0.01%, 0.006%, and 0.25%, respectively). There was an increase in the detection of atypical squamous cells of undetermined significance (ASCUS; 3.74% vs. 3.19%) and low-grade SIL (LSIL; 1.67% vs. 1.01%) with a decrease in the ASCUS-to-LSIL ratio from 3.15 for CS to 2.33 for TP. The detection of atypical glandular cells of undetermined significance (AGUS) increased slightly from 0.07% to 0.09%. The proportion of cells reported to have reactive atypia dropped from 2.71% to 1.48%. Limited biopsy correlation (range, 73.2-76.2%) confirmed the increased sensitivity of TP. More actinomyces (1.07% vs. 0.52%) were detected in TP samples despite of a similar portion of intrauterine-device users. The average primary screening and rapid rescreening time of each slide were reduced from 8 minutes to 4 minutes and from 2 minutes to less than 1 minute, respectively.

CONCLUSIONS

The preliminary experience of the authors of the current study appears to support the use of the ThinPrep Pap test to enhance the efficiency of cervical cytology screening.

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.

Papanicolaou tests and molecular analyses using new fluid-based specimen collection technology in 3000 Japanese women

A fluid-based Papanicolaou test has been established to improve sample collection and preparation. This study was the first large-scale investigation in Japan to examine the feasibility of using fluid-based Papanicolaou specimens to detect human papillomavirus (HPV) using Hybrid Capture II and polymerase chain reaction (PCR). Three thousand patients who visited Keio University Hospital between October 2000 and February 2001 were enrolled in the study. The results of the fluid-based Papanicolaou tests corresponded well with those of conventional Papanicolaou smears (96.8% concordance). The sensitivities of cervical neoplasia detection using the fluid-based Papanicolaou test (73.9%) and Hybrid Capture II (76.3%, P=0.55) were not significantly different. Among the cervical intraepithelial neoplasia 3 and squamous cell carcinoma specimens, HPV 16 and HPV 52 were predominantly detected using the PCR method. Although some DNA samples extracted from the fluid-based specimens were degradaded, PCR and direct sequencing could be performed without difficulty even after 1 year of specimen storage. We conclude that fluid-based Papanicolaou specimens can be applied to investigate HPV infection.

The evaluation of liquid-based 'Cyto-SED' cytology of bronchioalveolar lavage specimens in the diagnosis of pulmonary neoplasia against conventional direct smears

Historically, bronchioalveolar lavage (BAL) samples have been prepared by a direct smear (DS) technique. Recent advances in liquid-based cytology have led to a revolution in cytological specimen preparation. Cyto-SED system (CS) is a manual liquid-based cytology system, designed for small-scale use. A total of 137 samples from patients with radiographically detectable lesions underwent BAL procedures at Papworth Hospital NHS Trust over a 4-month period. After preparation for diagnostic purposes with the DS method, the remaining sample was prepared using the CS system. The slides produced were allocated a blind study number and screened by three independent screeners. The cellular morphology was well preserved and comparable between both techniques. Of the 137 patients, 38% were confirmed as malignant by cytology or histology; 71% of these malignant diagnosis were confirmed by the DS technique and 91% confirmed by the CS. The results demonstrate that the CS is a viable alternative to the DS technique. The cytological detail is clearly defined without a loss of three-dimensional information, thus aiding the differential diagnosis of malignancy. Cyto-SED cytology system yields a higher diagnostic accuracy than the conventional direct smear technique without compromising on cytological detail.

Positive predictive value of liquid-based and conventional cervical Papanicolaou smears reported as malignant

OBJECTIVES

The predictive value of cervical Papanicolaou (Pap) smears reported as "positive for malignancy," especially those obtained by the liquid-based method, has not been adequately assessed. The objectives of this study are to determine the positive predictive value of Papanicolaou smears with features of malignancy, to compare the accuracy of Papanicolaou smears obtained by the liquid-based method to those obtained by the conventional technique in this setting, and to study the factors influencing a false-positive cytologic diagnosis of malignancy.

MATERIALS AND METHODS

Pap smears significant for malignant cytology were identified at Fletcher Allen Health Care Hospital in Burlington, VT, from May 1, 1995, to April 30, 2001. A retrospective review of the hospital records and pathology reports was performed documenting patient characteristics, the collection technique, and the final histology. An independent review of the cytology and histology was performed. The positive predictive value and false-positive rate of malignant cytology were calculated for the liquid-based and conventional Pap smear techniques.

RESULTS

A total of 472,743 Pap smears were performed during the period specified. One hundred four Pap smears were reported as positive for malignancy, yielding a prevalence rate of 0.02%. A total of 68 patients had paired cytology and histology specimens. Malignant cytology was identified in 36 smears obtained by the liquid-based technique and 32 smears obtained by the conventional technique. A true-positive result, meaning malignant cytology confirmed by the presence of invasive carcinoma on histology, was obtained in 61 of 68 (89.7%) patients. A false-positive result, meaning malignant cytology not confirmed by histology, was obtained in 7 of the 68 (10.3%) patients. The false-positive rate of malignant cytology was 8.4% for the liquid-based technique and 12.5% for the conventional technique. All 7 false-positive smears were diagnosed with high-grade dysplasia by histology. Three of the 7 patients with high-grade dysplasia had previous treatment for dysplasia, one of whom was also pregnant at the time of the smear.

CONCLUSIONS

Malignant cervical Papanicolaou smear cytology has a high positive predictive value in the setting of gynecologic and nongynecologic malignancies. Previous treatment for cervical dysplasia or pregnancy may influence the false-positive rate of malignant cytology.

Determination of features indicating progression in atypical squamous cells with undetermined significance: human papillomavirus typing and DNA ploidy analysis from liquid-based cytologic samples

BACKGROUND

The Bethesda System of cervical cytologic findings introduced the term ASCUS (atypical squamous cells of undetermined significance) to cover the broad zone separating normal cytomorphology from definitive squamous intraepithelial lesions (SILs). The management of patients with ASCUS is particularly problematic as approximately 10% of ASCUS patients develop SIL and 1 per 1000 develop cervical carcinoma.

METHODS

Our aim was to demonstrate the combined use of polymerase chain reaction for human papillomavirus (HPV) typing and laser scanning cytometry for DNA content measurements in the subcategorization of ASCUS cases according to the risk for progression toward cancer. Liquid- based monolayer preparation (ThinPrep, Cytyc, Boston, MA) of the cytologic material was used for cytomorphologic analysis. DNA content measurements using laser scanning cytometry and direct sequencing of HPV using the consensus primers GP5+/GP6+ and MY09/MY11 were performed from the same material.

RESULTS

Twelve of the 44 cases (27.2%) with ASCUS carried a high-risk HPV genome whereas only 3 of the 195 normal control cases (1.5%) showed positivity for a high-risk HPV genome. Six of 12 (50%) of the high-risk HPV-positive ASCUS cases presented isolated cells with a DNA content above 5c, whereas cells with a DNA content above 9c were found in 3 of 12 cases (25%) and were exclusively found in combination with high-risk HPV infection. In these three cases, the histologic follow-up resulted in cervical intraepithelial neoplasia (CIN) I (one case) and CIN III (two cases). None of the other ASCUS or normal cases displayed DNA aneuploidy above 9c. They returned to normal cytology (within normal limits/benign cellular changes) in the follow-up.

CONCLUSIONS

Human papillomavirus typing and DNA content measurements may delineate a distinct group of ASCUS. Our preliminary data suggest that ASCUS cases with high-risk HPV positivity and with rare cells with abnormally high DNA content represent similar biologic features as high-grade SIL and are at elevated risk to develop cancer.

Cross sectional study of conventional cervical smear, monolayer cytology, and human papillomavirus DNA testing for cervical cancer screening

OBJECTIVES

To compare the sensitivity, specificity, and interobserver reliability of conventional cervical smear tests, monolayer cytology, and human papillomavirus testing for screening for cervical cancer.

DESIGN

Cross sectional study in which the three techniques were performed simultaneously with a reference standard (colposcopy and histology).

SETTING

Public university and private practices in France, with complete independence from the suppliers.

PARTICIPANTS

828 women referred for colposcopy because of previously detected cytological abnormalities and 1757 women attending for routine smears.

MAIN OUTCOME MEASURES

Clinical readings and optimised interpretation (two blind readings followed, if necessary, by consensus). Sensitivity, specificity, and weighted kappa computed for various thresholds of abnormalities.

RESULTS

Conventional cervical smear tests were more often satisfactory (91% v 87%) according to the Bethesda system, more reliable (weighted kappa 0.70 v 0.57), and had consistently better sensitivity and specificity than monolayer cytology. These findings applied to clinical readings and optimised interpretations, low and high grade lesions, and populations with low and high incidence of abnormalities. Human papillomavirus testing associated with monolayer cytology, whether systematic or for atypical cells of undetermined significance, performed no better than conventional smear tests.

CONCLUSIONS

Monolayer cytology is less reliable and more likely to give false positive and false negative results than conventional cervical smear tests for screening for cervical cancer.

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.