A three-armed trial of the ThinPrep Imaging System

Digital cytology part 2: artificial intelligence in cytology: a concept paper with review and recommendations from the American Society of Cytopathology Digital Cytology Task Force

Digital cytology and artificial intelligence (AI) are gaining greater adoption in the cytology laboratory. However, peer-reviewed real-world data and literature are lacking in regard to the current clinical landscape. The American Society of Cytopathology in conjunction with the International Academy of Cytology and the Digital Pathology Association established a special task force comprising 20 members with expertise and/or interest in digital cytology. The aim of the group was to investigate the feasibility of incorporating digital cytology, specifically cytology whole slide scanning and AI applications, into the workflow of the laboratory. In turn, the impact on cytopathologists, cytologists (cytotechnologists), and cytology departments were also assessed. The task force reviewed existing literature on digital cytology, conducted a worldwide survey, and held a virtual roundtable discussion on digital cytology and AI with multiple industry corporate representatives. This white paper, presented in 2 parts, summarizes the current state of digital cytology and AI practice in global cytology practice. Part 1 of the white paper is presented as a separate paper which details a review and best practice recommendations for incorporating digital cytology into practice. Part 2 of the white paper presented here provides a comprehensive review of AI in cytology practice along with best practice recommendations and legal considerations. Additionally, the cytology global survey results highlighting current AI practices by various laboratories, as well as current attitudes, are reported.

Cost-effectiveness of artificial intelligence-assisted liquid-based cytology testing for cervical cancer screening in China

Background

The 2021 World Health Organization (WHO) guidelines for cervical cancer screening recommend human papillomavirus (HPV) DNA or mRNA testing. Artificial intelligence (AI)-assisted liquid-based cytology (LBC) systems also have the potential to facilitate rapid scale-up of cervical cancer screening. We aimed to evaluate the cost-effectiveness of AI-assisted LBC testing, compared with the manual LBC and HPV-DNA testing, for primary cervical cancer screening in China.

Methods

We developed a Markov model for a cohort of 100,000 women aged 30 years over a lifetime to simulate the natural history of cervical cancer progression. We evaluated the incremental cost-effectiveness ratios (ICER) of 18 screening strategies (a combination of the three screening methods with six screening frequencies) from a healthcare provider's perspective. The willingness-to-pay threshold (US$30,828) was chosen as three times the Chinese per-capita gross domestic product in 2019. Univariate and probabilistic sensitivity analyses were performed to examine the robustness of the results.

Findings

Compared with no screening, all 18 screening strategies were cost-effective, with an ICER of $622-24,482 per quality-adjusted life-year (QALY) gained. If HPV testing after scaling up to population level screening costs $10.80 or more, screening once every 5 years using AI-assisted LBC would be the most cost-effective strategy with an ICER of $8790/QALY gained compared with the lower-cost non-dominated strategy on the cost-effectiveness frontier. Its probability of being cost-effective was higher (55.4%) than other strategies. Sensitivity analyses showed that the most cost-effective strategy would become AI-assisted LBC testing once every 3 years if the sensitivity (74.1%) and specificity (95.6%) of this method were both reduced by ≥10%. The most cost-effective strategy would become HPV-DNA testing once every 5 years if the cost of AI-assisted LBC was more expensive than manual LBC or if the HPV-DNA test cost is slightly reduced (from $10.8 to <$9.4).

Interpretation

AI-assisted LBC screening once every 5 years could be more cost-effective than manually-read LBC. Using AI-assisted LBC could have comparable cost-effectiveness to HPV DNA screening, but the relative pricing of HPV DNA testing is critical in this result.

Funding

National Natural Science Foundation of China, National Key R&D Program of China.

ThinPrep® imaging system-assisted vs manual screening of urinary cytology slides in the detection of the "suspicious for high-grade urothelial carcinoma" category

BACKGROUND

The ThinPrep® Imaging System (TIS) is a Food and Drug Administration-approved review system for cervical cytopathology, where it has been shown to increase performance over manually reviewed slides. Application of the TIS to urinary cytology has only been reported in a single study, in 2013.

METHODS

We aimed to compare the agreement of two cytotechnologists' and a pathologist's manual screening (dots) with the fields of view (FOVs) selected by the TIS. We also aimed to track cases in which the TIS could identify missed abnormals and reduce the false-negative fraction. Electronically marked TIS fields (EMTFs) suspicious for high-grade urothelial carcinoma (SHGUC) were controlled by follow-up cystoscopy and histology, where available.

RESULTS

A total of 826 consecutive specimens were studied. Of those, 94 (11.4%) were unreadable by the TIS. There were 710 possible comparisons, of which 380 (53.5%) received no dot after manual screening. Of the 330 remaining slides, 149 (45.1%) had at least one dot matching with the TIS FOVs. After TIS reading, EMTFs were noted in 13 of 636 (2.0%) negative cytology cases. Surveillance showed that 3/13 (23.1%, 0.4% of the 710 possible comparisons) of those cases matched with high grade urothelial carcinoma (HGUC), whereas 6/13 (46.1%, 0.8% of the 710 possible comparisons) had negative follow-up at 24 months, and 4/13 (30.8%) were lost for follow-up.

CONCLUSION

The TIS increases the detection rate of SHGUC cells, potentially leading to a slight decrease in the false-negative fraction, but at the expense of a slight but larger increase in the number of false-positive cases. These findings stress the importance of a careful approach to the evaluation of the FOVs.

Cervical cancer: Automation of Pap test screening

BACKGROUND

Cervical cancer progresses slowly, increasing the chance of early detection of pre-neoplastic lesions via Pap exam test and subsequently preventing deaths. However, the exam presents both false-negatives and false-positives results. Therefore, automatic methods (AMs) of reading the Pap test have been used to improve the quality control of the exam. We performed a literature review to evaluate the feasibility of implementing AMs in laboratories.

METHODS

This work reviewed scientific publications regarding automated cytology from the last 15 years. The terms used were "Papanicolaou test" and "Automated cytology screening" in Portuguese, English, and Spanish, in the three scientific databases (SCIELO, PUBMED, MEDLINE).

RESULTS

Of the resulting 787 articles, 34 were selected for a complete review, including three AMs: ThinPrep Imaging System, FocalPoint GS Imaging System and CytoProcessor. In total, 1 317 148 cytopathological slides were evaluated automatically, with 1 308 028 (99.3%) liquid-based cytology slides and 9120 (0.7%) conventional cytology smears. The AM diagnostic performances were statistically equal to or better than those of the manual method. AM use increased the detection of cellular abnormalities and reduced false-negatives. The average sample rejection rate was ≤3.5%.

CONCLUSION

AMs are relevant in quality control during the analytical phase of cervical cancer screening. This technology eliminates slide-handling steps and reduces the sample space, allowing professionals to focus on diagnostic interpretation while maintaining high-level care, which can reduce false-negatives. Further studies with conventional cytology are needed. The use of AM is still not so widespread in cytopathology laboratories.

Comparison of ThinPrep Integrated Imager-Assisted Screening versus Manual Screening of ThinPrep Liquid-Based Cytology Specimens

OBJECTIVE

The aim of this study was to find out whether ThinPrep Integrated Imager (Hologic Inc.) screening is non-inferior to manual screening in the detection of cervical lesion.

STUDY DESIGN

For a total of 4,011 ThinPrep Pap test specimens stained by ThinPrep staining, manual screening (Manual arm) and ThinPrep Integrated Imager screening (Imager arm) were performed so as not to be screened by the same cytotechnologist, and the sensitivity and specificity in the detection of cervical lesion were compared using McNemar's test.

RESULTS

The sensitivity to detect CIN1 or more squamous cell abnormalities or glandular abnormalities was 91.67% (= 374/408, 95% confidence interval [CI]: 88.44-94.08%) for the Manual arm and 92.40% (= 377/408, 95% CI: 89.28-94.70%) for the Imager arm, and the specificity was 88.87% (= 3,113/3,503, 95% CI: 87.77-89.88%) for the Manual arm and 89.55% (= 3,137/3,503, 95% CI: 88.48-90.54%) for the Imager arm. The differences in sensitivity and in specificity, respectively, were 0.74% (95% CI: -3.14-4.61%, McNemar's test, p = 0.8041) and 0.69% (95% CI: -0.13-1.50%, McNemar's test, p = 0.1125). About the equality of sensitivity and specificity between the 2 methods, 95% CIs of the difference between sensitivity and specificity are in the clinical equivalence range of ±5%, so the Imager arm is non-inferior to the Manual arm.

CONCLUSION

The Imager arm was confirmed to have an equivalent and non-inferior capacity in the detection of cervical lesions compared with the Manual arm, suggesting that its practical application in cervical cytology tests is highly possible.

A Review of Computational Methods for Cervical Cells Segmentation and Abnormality Classification

Cervical cancer is the one of the most common cancers in women worldwide, affecting around 570,000 new patients each year. Although there have been great improvements over the years, current screening procedures can still suffer from long and tedious workflows and ambiguities. The increasing interest in the development of computer-aided solutions for cervical cancer screening is to aid with these common practical difficulties, which are especially frequent in the low-income countries where most deaths caused by cervical cancer occur. In this review, an overview of the disease and its current screening procedures is firstly introduced. Furthermore, an in-depth analysis of the most relevant computational methods available on the literature for cervical cells analysis is presented. Particularly, this work focuses on topics related to automated quality assessment, segmentation and classification, including an extensive literature review and respective critical discussion. Since the major goal of this timely review is to support the development of new automated tools that can facilitate cervical screening procedures, this work also provides some considerations regarding the next generation of computer-aided diagnosis systems and future research directions.

Prevention of Cervical Cancer: Guideline of the DGGG and the DKG (S3 Level, AWMF Register Number 015/027OL, December 2017) - Part 1 with Introduction, Screening and the Pathology of Cervical Dysplasia

Aims Annual opportunistic screening for cervical carcinoma has been carried out in Germany since 1971. The creation of this S3 guideline meets an important need, outlined in the National Cancer Plan, with regard to screening for cervical cancer, as the guideline aims to provide important information and support for planned organized screening for cervical cancer in Germany. Methods With the financial support of German Cancer Aid, 21 professional societies developed evidence-based statements and recommendations (classified using the GRADE system) for the screening, management and treatment of precancerous conditions of the cervix. Two independent scientific institutes compiled systematic reviews for this guideline. Recommendations The first part of this short summary presents the pathological basis and considers various questions related to screening for cervical cancer. As also reported in earlier reviews, the meta-analysis by Kleijnen Systematic Reviews showed that HPV-based screening offers better protection against invasive cervical cancer compared to cytology-based screening. The authors of this guideline therefore recommend - in accordance with the guideline of the Joint National Committee of Germany (Gemeinsamer Bundesauschuss, G-BA) - that women aged 35 and above should be examined at regular intervals (at least every 3 years) and undergo HPV-based screening. Co-testing can also be carried out. Women between the ages of 20 and 35 should have cytological screening every 2 years.

Time consumed by microscopic and nonmicroscopic tasks in image-assisted gynecologic screening: Implications for workload assessment

BACKGROUND

Gynecologic screening cytology is a complex task that includes microscopic activities and nonmicroscopic activities. The authors sought to determine the amount and percentage of time that cytotechnologists spend on those activities using the ThinPrep imaging system.

METHODS

In arm 1, a total of 550 consecutive unselected slides were reviewed by 11 cytotechnologists, and the time used for individual subtasks of the screening process was recorded. In arm 2, a total of 20 unselected slides were each screened by 10 different cytotechnologists (200 slides in total) and total screening times and full manual review (FMR) times were recorded.

RESULTS

In arm 1, cases with and without FMR required an average of 5.6 minutes and 3.0 minutes, respectively, to screen. Overall, review of fields of view (FOVs) took 95 seconds. FMR took an average of 2.6 minutes. The average screening times for FOV-only cases was significantly longer than the US Food and Drug Administration/Centers for Medicare and Medicaid Services (FDA/CMS) workload limit of 2.4 minutes (P = .005). However, in arm 2, the time needed to screen a case increased by an average of 1 minute compared with arm 1, including 1.1 minute for FOV-only cases and >2 minutes for FMR plus FOV cases. Approximately 100% of cases screened as FOV only exceeded the FDA/CMS workload limit of 2.4 minutes.

CONCLUSIONS

The FDA/CMS workload limits for FOV-only cases appears to significantly underestimate the time needed to screen those cases, but seems to be appropriate for the majority of FMR plus FOV cases. Approximately 60% and 30% of the time designated to screening slides was spent on nonmicroscopic activities for FOV-only cases and FMR cases, respectively. Cancer Cytopathol 2016;124:501-7. © 2016 American Cancer Society.

Is there a role for the thinprep imaging system in reporting anal cytology?

BACKGROUND

The ThinPrep Imaging System (TIS) is an accurate time-saving method of reading cervical ThinPrep slides in screening programs. As anal and cervical cytology are morphologically similar, TIS can potentially be used for anal cytology. We assessed the performance of TIS on anal ThinPrep slides from homosexual men in a natural history study of human papillomavirus-related anal abnormalities.

METHODS

Four hundred nineteen anal cytology slides were processed by TIS and classified by a cytologist as either No further review (slide archived) or Manual review (slide requiring full manual screen). The results were compared with the original manual screening report for all slides and specifically for those screening episodes accompanied by a high-grade squamous intraepithelial lesion (HSIL) on concurrent biopsy.

RESULTS

One hundred seventy six of 419 (42.0%) slides were classified as No further review, with a trend of decreasing proportions as the degree of severity of the cytological abnormality increased. Thirteen (27.7%) slides with an original unsatisfactory report were classified as No further review. Eighty two (92.1%) of those with biopsy HSIL and cytological abnormality were classified for Manual review, including all 45 (100%) with cytological HSIL.

CONCLUSION

The cervical algorithm of TIS performed best on anal samples when HSIL was present both cytologically and histologically. The 27.7% unsatisfactory slides classified as No further review may indicate need for use of different criteria from cervical cytology. Because of the high prevalence of abnormalities, and hence the large proportion of slides needing manual review, the cytologist time-saving would compare unfavorably with use of TIS in cervical screening.

Comparative analysis of cervical cytology screening methods and staining protocols for detection rate and accurate interpretation of ASC-H: Data from a high-volume laboratory in Turkey

BACKGROUND

This study evaluated the effectiveness of the ThinPrep(®) Imaging System (TIS) and ThinPrep(®) Pap Stain (TPPS). A comparative analysis was conducted to determine the detection rates of atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion (ASC-H), the ASC:squamous intraepithelial lesion (SIL) ratio, biopsy follow-up for ASC-H in terms of the screening method used (manual screening [MS] vs. TIS screening [TISS]) and the staining protocol (regular Pap stain [RPS] vs. TPPS).

METHODS

This study was performed over two periods. The RPS period included manually screened slides, whereas the TPPS period included TIS + manually screened slides. All data from the study periods were compared using statistical analysis.

RESULTS

The detection rate of ASC-H was significantly higher during the TPPS period than during the RPS period (0.49% vs. 0.23%); this finding is in contrast to the insignificant difference between the screening method periods. The positive predictive value (PPV) of ASC-H cytodiagnosis for cervical intraepithelial neoplasia of grade 2 or more severe histologies was significantly different between manually screened and TIS slides (22.10% vs. 38.55%), in contrast to an insignificant difference between RPS and TPPS periods (37.14% vs. 29.77%).

CONCLUSION

Implementation of the TIS did not change the ASC-H detection rates appreciably. However, the new technology improved PPV for ASC-H cytodiagnosis and enabled the detection of true disease. Our laboratory statistics indicate that the TPPS is not a superior staining protocol and did not increase our diagnostic accuracy for ASC-H compared with RPS.

A comparison of ThinPrep Imager-assisted with manual screening, and its place in the New Zealand cervical cancer screening program

AIMS

Overseas studies have shown equivalent sensitivity and specificity between computer-assisted screening and manual screening, with increased screener productivity. This study was undertaken to test these in a New Zealand laboratory setting.

METHODS

A total of 9232 slides were read manually alone, and following ThinPrep Imager-assisted screening, and the results compared. Two senior screeners and a cytopathologist reviewed the slides with discordant results.

RESULTS

The detection rate for abnormalities was 7.30% for Imager-assisted screening and 7.83% for manual screening. The concordance in diagnosis of abnormalities ranged from 72.7% to 100% with the lowest concordance for high-grade abnormalities diagnosed by Imager-assisted screening. The rate of unsatisfactory smears with Imager-assisted screening is half that of manual screening. There was a screener productivity increase of 140%. In all but one case, abnormal cells were identified by the Imager but screeners varied in their interpretations.

CONCLUSIONS

Overall, Imager-assisted screening was as sensitive as manual screening, and more sensitive for high-grade lesions, with a halving of the rate of unsatisfactory smears. In the setting of the New Zealand cervical screening program, the initial screen by the Imager removes the need for a second, rapid rescreen required by the program for manual screening.

Uptake of liquid-based cytology as an adjunct to conventional cytology for cervical screening in NSW, Australia: a cross-sectional and population-based cohort analysis

BACKGROUND

Cervical screening is currently recommended every two years in sexually active women aged 18-20 to 69 years in Australia. Direct replacement of conventional cytology with liquid-based cytology (LBC) for cervical screening was rejected for public funding on grounds of cost-effectiveness, first in 2002 and again in 2009, but LBC is performed as an adjunct to conventional cytology in women who elect to pay. The objective of this study was to describe prevalence and predictors of use of LBC in Australia's most populous state, New South Wales (NSW).

METHODS

We performed cross-sectional and population-based cohort analyses using data from the state Pap Test Register in NSW. We calculated the age-adjusted proportion of women aged 20-69 years electing to have adjunctive LBC over the period from 2006-2010. We also calculated the fully-adjusted odds ratios for the association between subsequent LBC use and age, socioeconomic status, place of residence, previous cytological history and provider type in a cohort of 360,247 women who had an index cervical cytology test in 2006-8.

RESULTS

Uptake of LBC varied between 29.7% (95% Confidence Interval (CI): 29.5-30.0%) in 2006/7 and 26.6% (95% CI: 26.4-26.9%) in 2009/10. LBC was more likely to be used in women aged 30-44 years, if it had been used previously (OR13.58, 95% CI: 13.33-13.84), if the previous test result was abnormal (OR2.62, 95% CI:2.53-2.72) or unsatisfactory (OR2.37, 95% CI:2.27-3.47), or if a gynaecologist requested the test (OR1.50, 95% CI:1.46-1.54). Uptake was least for women in remote/very remote areas (OR0.68; 95% CI:0.57-0.80 referenced to those in major cities) and in lower socioeconomic groups (OR 0.41, 95% CI:0.40-0.42 for lowest versus highest SES quintile).

CONCLUSION

In the current environment in NSW, Australia, in which public funding for LBC has not been available, adjunctive uptake of LBC depends strongly on a woman's age, her screening history and socioeconomic factors. These findings provide important context for a current review of technologies used in the National Cervical Screening Program in Australia.

Cervical Pap screening among Israeli women, 2005-2010

PURPOSE

This study describes the distribution and the trends of cervical abnormalities in Israel, based on Pap smear results.

METHODS

A retrospective analysis of cervical smears received by the Central Pathology Laboratory of Maccabi Healthcare Services between January 2005 and December 2010.

RESULTS

In total, 711,541 Pap smears were screened in the study period. Cytological abnormalities were observed in 4.78% of the total smears screened. An increase was observed in the rate of positive results from 2.63% in 2005 to 6.78% in 2010 (p = 0.0026). The cervical abnormalities in the study period distributed as follows: atypical squamous cell (ASC)-2.72%, low-grade squamous intraepithelial lesion (LSIL)-1.54%, high-grade squamous intraepithelial lesion (HSIL)-0.34%, squamous cell carcinoma-0.01%, atypical glandular cells (AGC)-0.10%, adenocarcinoma in situ (AIS)-0.06% and invasive adenocarcinoma-0.01%. The increase was statistically significant for ASC (p = 0.0028), LSIL (p = 0.0069) and for HSIL (p = 0.0260). The mean ages at diagnosis of women with ASCUS, LSIL, HSIL, squamous cell carcinoma, AGC, AIS and adenocarcinoma were 37.8, 33.2, 38.6, 55.4, 41.1, 49.9 and 57.1 years, respectively.

CONCLUSIONS

The increase in the rate of squamous cell abnormalities demonstrated in this study emphasizes the need of implementing an education and a screening program among Israeli women. HPV vaccine, sexual behavior, cytology performance and HPV test are primary and secondary prevention tools which may reduce morbidity and mortality in the future. In addition, based on the age at diagnosis of the different pathologies, the age group in which Pap test is performed in Israel should be expanded from 35-54 to 25-65 years.

Imaging systems and urine specimens: a new match made?

The application of standard cytologic examination of the urine specimen can now be augmented by using ThinPrep technology and other automatic screening devices. The technical and preparation adjustments required for these new technologies notwithstanding, the potential for shorter screening times and the possibility of greater diagnostic accuracy may provide great diagnostic promise for this very common specimen.

Application of the ThinPrep imaging system in urine cytology: a prospective study

BACKGROUND

In this prospective study, for the first time, the authors compared the accuracy of reading urine specimens using the ThinPrep Imager System (TIS) with the accuracy of conventional screening for the detection of abnormal urine cells.

METHODS

ThinPrep slides were made from 1455 urine specimens and were read with conventional screening and with TIS. Findings were categorized as "unsatisfactory or failure to read the slide," "benign," or "abnormal." The Cohen κ coefficient was calculated to determine inter-rater agreement between both methods. Urine samples that were followed by biopsies were used to compare the sensitivity, specificity, positive predictive value, and negative predictive value of both methods. From 22 urine specimens, the screening times were measured and compared.

RESULTS

There was substantial agreement between both methods (κ score, 0.77). Of 175 urine specimens that were followed by bladder biopsies, for conventional screening, the sensitivity was 51.3%, specificity was 68.4%, the positive predictive value was 77.2%, and the negative predictive value was 40.2%; for TIS screening, the respective values were 54.6%, 68.4%, 78.3%, and 41.9%. The average time was 5.2 minutes for conventional screening and 3.9 minutes for TIS.

CONCLUSIONS

With a κ score of 0.77, the current study demonstrated a good correlation between reading urine specimens with conventional screening and with TIS. Using TIS resulted in slightly increased sensitivity, positive predictive value, and negative predictive value compared with conventional screening and had the same specificity. These results indicate that reading urine specimens using TIS is equally reliable as conventional cytology.

Effect of Thin Prep(®) imaging system on laboratory rate and relative sensitivity of atypical squamous cells, high-grade squamous intraepithelial lesion not excluded and high-grade squamous intraepithelial lesion interpretations

Introduction:

Automated screening of Thin Prep^® Papanicolaou Tests has become increasingly common in clinical practice. Increased productivity has initiated laboratory use of the Thin Prep^® Imaging System (TIS). Increased sensitivity is a potential additional benefit of TIS. Published studies have shown an increase in discovery of dysplastic cells. This study evaluates the effect of TIS on the incidence of atypical squamous cells high-grade squamous intraepithelial lesion not excluded (ASC-H) and high-grade squamous intraepithelial lesion (HGSIL) results on Thin Prep^® Pap Tests by comparing TIS-assisted and manual screening findings and the diagnoses on subsequent follow-up in a screening population over a 1-year time period.

Materials and Methods:

A compilation of all ASC-H and HGSIL cases was prepared by conducting a computerized search over a 1-year period (7/06-6/07). The accumulated cases include Thin Prep Pap tests that were both TIS and manually screened. Follow-up results of cytologic and histologic cervical specimens were obtained for a time period extending to 2010. Interpretation utilizing TIS was in place 10 months prior to the study's initiation.

Results:

During the study period 70,522 Pap tests were performed in our laboratory. One third (33%) of Pap tests were screened with assistance of TIS. Manual screening was performed on 47,380 Pap tests of which 153 (0.32%) were interpreted as ASC-H and 164 (0.35%) were interpreted as HGSIL. During the same time period automated screening (TIS) was performed on 23,111 Pap tests. Interpretation of 62 (0.27%) cases provided an ASC-H result, while 71 (0.31%) were HGSIL. Follow-up cervical dysplasia by colposcopic biopsy and cone biopsy was distributed proportionally between TIS and manual screening for both ASC-H and HGSIL categories. Cervical intraepithelial neoplasia (CIN II/III) was identified on follow-up biopsy of 41% TIS cases and 45% manually screened cases for ASC-H. In the HGSIL subset 71% of TIS cases and 69% manually screened cases showed CIN II/III on follow-up. TIS was 26% less sensitive relative to manual screening for ASC-H cases and 3% less sensitive for HGSIL.

Conclusion:

The similar rate of detection using TIS with an equal percentage of histologic correlation for ASC-H and HGSIL lesions on follow-up histology suggests patients screened by the TIS method are being sent for appropriate follow-up surveillance and treatment. A high-grade or possible high-grade lesion is as likely to be detected by TIS as by a manual screen. The similarities in relative sensitivity and specificity in a direct comparison between manual and TIS screening methodologies indicate that TIS compared to manual screening does not affect detection in patients with high-grade cervical lesions.

A randomized trial comparing conventional cytology to liquid-based cytology and computer assistance

Liquid-based cytology (LBC) has replaced conventional cytology (CC) for cervical cancer screening in some countries. However, it remains unclear whether LBC is superior to CC. A randomized controlled trial was conducted between August 2007 and March 2009 in Germany to compare LBC, alone and in combination with computer-assisted imaging technology (CAS), to CC in the detection of histologically confirmed cervical intraepithelial neoplasia (CIN). The main outcome measures were detection rates, relative sensitivities, positive predictive values (PPVs) and relative PPVs comparing LBC without and with CAS to CC. Primary histological outcome was CIN2 or higher. Included were 20,627 women participating in opportunistic cervical cancer screening at 20 gynecologic practices. The practices were randomized weekly to use LBC (n = 11,331) or CC (n = 9,296). Patients with positive findings were invited to expert colposcopy. The relative sensitivity of LBC versus CC using the CIN2+ cut-off was 2.74 (95% confidence interval [CI] 1.66-4.53). The relative sensitivity of LBC/CAS versus CC for CIN2+ was 3.17 (95% CI 1.94-5.19). The PPV of LBC and CC for CIN2+ was 48% and 38%, respectively. The PPV ratio did not differ significantly from unity. Differences between LBC and CC were smaller in some sensitivity and subgroup analyses; however, relative sensitivity of LBC remained increased. LBC without and with CAS compared with CC under the field conditions of an opportunistic screening system had a significantly higher sensitivity for the detection of CIN without deterioration of PPVs. Additional use of CAS did not further improve sensitivity of LBC. © 2012 Wiley Periodicals, Inc.

Increasing cytotechnologist workload above 100 slides per day using the BD FocalPoint GS imaging system negatively affects screening performance

Studies examining the effects of increased workload on the performance of individual cytotechnologists are limited. Using FocalPoint GS, the performance of 3 cytotechnologists was evaluated. The study consisted of 3 phases. In phase I, cytotechnologists were asked to screen at their usual pace. In phase II, cytotechnologists were asked to screen as fast as possible without feeling that the quality of their work was diminished. In phase III, cytotechnologists were asked to screen at least 15% more than their daily workload from phase II. Productivity was increased by decreasing the percentage of cases that underwent full manual review (from 38% to 19%) and by decreasing the time spent on each slide (from 5.5 min to 3.7 min). Overall, the total abnormal rate decreased by 31.9% from phase I to phase III of the study. In addition, the false-negative fraction increased significantly, from 1% to 6.9%. Our results indicated a negative association between increased cytotechnologist daily workload with FocalPoint GS and CT screening performance. Workloads were increased by decreasing the time spent reviewing 10 fields of view and the percentage of cases that underwent full manual review.

Liquid-based cervical cytology using ThinPrep technology: weighing the pros and cons in a cost-effectiveness analysis

PURPOSE

Cervical cancer screening with liquid-based cytology (LBC) has been developed as an alternative to the conventional Papanicolaou (CP) smear. Cost-effectiveness is one of the issues when evaluating LBC. Based on the results of a Dutch randomised controlled trial, we conducted cost-effectiveness threshold analyses to investigate under what circumstances manually screened ThinPrep LBC is cost-effective for screening.

METHODS

The MISCAN-Cervix microsimulation model and data from the Dutch NETHCON trial (including 89,784 women) were used to estimate the costs and (quality-adjusted) life years ((QA)LYs) gained for EU screening schedules, varying cost-effectiveness threshold values. Screening strategies were primary cytological screening with LBC or CP, and triage with human papillomavirus (HPV) testing.

RESULTS

Threshold analyses showed that screening with LBC as a primary test can be cost-effective if LBC is less than <euro>3.2 more costly per test than CP, if the sensitivity of LBC is at least 3-5 % points higher than CP, if the quality of life for women in triage follow-up is only 0.39, or if the rate of inadequate CP smears is at least 16.2 %.

CONCLUSIONS

Regarding test characteristics and costs of LBC and CP, only under certain conditions will a change from CP to manually screened ThinPrep LBC be cost-effective. If none of these conditions are met, implementation of manually screened ThinPrep LBC seems warranted only if there are advantages other than cost-effectiveness. Further research is needed to establish whether other LBC systems will be more favorable with regard to cost-effectiveness.

Prospective parallel randomized trial of the MultiCyte™ ThinPrep(®) imaging system: the Scottish experience

BACKGROUND

Computer-assisted screening of cervical liquid-based cytology (LBC) preparations using the ThinPrep® Imaging System (TIS) has shown improved qualitative and quantitative gains. The use of Multicyte™ has not been described in a well-established national screening programme with a low incidence of high-grade dyskaryosis.

OBJECTIVES

To assess the impact of computer-assisted screening within the Scottish Cervical Screening Programme (SCSP).

METHODS

Two groups of three laboratories, each sharing a ThinPrep® Imager, screened 79 366 slides randomized to test and 90 551 to control arms by laboratory accession. Screeners were not blinded. Standard laboratory reporting profiles of the SCSP, sensitivity, specificity and false-negative rates of all grades of LBC abnormalities with respect to final cytology reports, predictive value for cervical intraepithelial neoplasia grade 2 or worse (CIN2+) on histology; and screening rates were compared for both arms.

RESULTS

Inadequate and negative reporting rates were significantly lower and low-grade reporting rates significantly higher in the imager arm. Imager-assisted screening showed significantly better specificity than manual screening with respect to the final cytology result. There was no evidence of a significant difference in the detection of CIN2+ or CIN3 +. Positive, abnormal and total predictive values (high-grade, low-grade and all abnormal cytology found to be CIN2+, respectively) were similar in both arms. Productivity was significantly higher in the imager arm.

CONCLUSION

  Computer-assisted screening in a well established screening programme showed significantly improved productivity without loss of quality. These findings should inform future policy for cervical screening programmes.

Comparison of the sensitivity of conventional cytology and the ThinPrep Imaging System for 1,083 biopsy confirmed high-grade squamous lesions

Liquid-based cytology continues to be utilized as an adjunct to conventional cytology in most Australian laboratories, even though a direct-to-vial ThinPrep protocol has been introduced in many countries with established cervical screening programs. Manual screening of ThinPrep slides has been widely practiced for more than 10 years and the recent introduction of the ThinPrep Imaging System (TPI) has been reported as being more sensitive than the conventional smear (CS) in the identification of high-grade cervical disease.We report our experience with ThinPrep Imaging since its introduction into our routine gynecological cytology service. 87,284 split sample pairs reported using the Imaging System demonstrated a decrease in unsatisfactory reports (3.65% for CS and 0.87% for TPI) and an increase in possible high grade and definite high-grade squamous reports (1.57% for CS and 1.62% for TPI).For 1,083 biopsy confirmed high-grade lesions, the correct diagnosis of high grade or possible high-grade squamous disease was made on the ThinPrep imaged slide in 61.0% (661/1,083) of cases and on the CS in 59.4% (643/1,083). This was not statistically significant. When all abnormalities identified on cytology were considered, including possible low grade and definite low-grade abnormalities, the difference in sensitivity for Thinprep imaged slides of 96.0% (1,040/1,083) and CSs of 91.6% (992/1,083) was statistically significant.

Should liquid-based cytology be performed prior to colposcopy? A comparison of the accuracy, unsatisfactory rates and cost in a tertiary referral setting

OBJECTIVE

To compare the use of liquid-based cytology (LBC) with conventional cytology (CC) in the assessment cervical intraepithelial neoplasia (CIN) prior to colposcopy.

DESIGN

Retrospective Cohort Study.

METHODS

Liquid-based cytology and CC findings were compared with colposcopic assessment and directed cervical biopsy in terms of sensitivity and specificity for high grade lesions only and for any abnormalities. The degree of correlation was sought. Secondary outcomes were unsatisfactory rate and cost.

RESULTS

A total of 1961 women had colposcopy of whom 528 had cervical biopsy. LBC and CC have similar sensitivity and specificity for both high-grade lesions and any abnormalities. In comparison with cervical biopsy, LBC and CC sensitivity for high-grade disease was 89.1% and 88.6% respectively and for any abnormalities, the sensitivity was 86.6% and 87.0%. Specificity for high-grade disease was 83.1% and 84.7% and for any abnormalities, the specificity was 53.8% and 56.4%. The unsatisfactory rate was significantly lower in LBC 4.38% compared to 1.84% (P < 0.001). However, the use of LBC was associated with an additional cost of A$1496 for each unsatisfactory smear avoided.

CONCLUSION

In high prevalence setting, LBC showed no statistically significant difference in sensitivity and specificity from CC for the detection of CIN. A reduction in unsatisfactory smears was evident, but at significant additional cost.

Controls in quality assessment in gynecologic cytology: A rational approach to workload limits for the ThinPrep imaging system

Major components of good quality assurance (QA) in cytology laboratories are measuring the screening accuracy of cytotechnologists (CTs) and determining appropriate workload limits for them. Currently, the FDA approved workload limits for image assisted Paps, however, are too high. In addition, the CLIA 88 mandated QA measures, by themselves, are insufficient to accurately measure the screening performance of CTs. Although the use of "controls" is fundamental to good practice in the clinical laboratory; this has not been emphasized in gynecologic cytology. In this review, we underscore the importance of using controls, such as monitoring morning and afternoon abnormal rates, in assessing CT performance and assigning reasonable workload limits. Using controls, however, requires significant alteration in the laboratory workflow, and much lower and variable workload limits for CTs, compared to those approved by FDA.

Image-guided ThinPrep Papanicolaou tests and cotesting with high-risk human papillomavirus in women aged 30 years and older in a low-risk private practice population

BACKGROUND

Screening for cervical cancer precursors has evolved considerably with the introduction of new technologies to improve the early detection of disease. The objective of this study was to analyze the accuracy and effectiveness of combined screening with cytology and high-risk human papillomavirus (HR-HPV) testing in a low-risk population of women aged >or=30 years.

METHODS

Consecutive unselected samples from a group of 1871 women aged >or=30 years were screened with image-guided ThinPrep tests and HR-HPV tests during a 6-month period. Histologic follow-up was reviewed among women with positive HR-HPV tests.

RESULTS

A total of 85 (4.5%) women had positive HR-HPV tests. In 48 HR-HPV-positive women with follow-up biopsies, 41 (85%) were found to have histologic abnormalities. Thirty-three (1.9%) women with cytologically normal Papanicolaou (Pap) tests harbored HR-HPV, and a cervical intraepithelial neoplasia (CIN) 2+ lesion was detected in 1 (16%) of 6 women with histologic follow-up. Conversely, 2 (28%) of 7 women with high-grade intraepithelial lesion on cytology tested negative for HR-HPV during the same period. A case of serous carcinoma with atypical glandular cells on cytology was also negative for HR-HPV, as expected.

CONCLUSIONS

In this low-risk population of women aged >or=30 years, histology-confirmed CIN2+ lesions were identified in women with negative cytology and positive HR-HPV tests, as well as in those with positive cytology and negative HR-HPV tests. Because both cytology and HPV testing alone missed significant lesions, cotesting with Pap and HR-HPV in women aged >or=30 years appears to be a reasonable option in a low-risk population.

Implementation of the ThinPrep Imaging System in a tertiary military medical center

BACKGROUND

The ThinPrep Imaging System (TIS) was implemented at Brooke Army Medical Center (BAMC) in February 2006 and has been a crucial part of the ability of the Department of Pathology and Laboratory Services ability to improve efficiency and turnaround times for Papanicolaou (Pap) test reporting. The increased detection rate of squamous abnormalities, specifically high-grade squamous intraepithelial lesions (HSIL), has been well documented by many studies. In addition, the TIS has increased productivity for many laboratories. The objective of this study was to evaluate the effects of implementing the TIS at BAMC, a tertiary military medical center. Specifically, the following were assessed: 1) whether the detection of squamous abnormalities was increased with the TIS, 2) how the rate of high-risk human papillomavirus (HR-HPV) detection in atypical squamous cells (ASC) of undetermined significance (ASC-US) cases changed (or did not change) before and after implementation of the TIS, and 3) how the TIS influenced productivity.

METHODS

All gynecologic cytology at BAMC has been collected and processed using the ThinPrep system since 2002. Before February 2006 and before implementation of the TIS, Pap tests were screened manually by the cytotechnologists. Detection rates of squamous abnormalities were compared between the period from February 2005 to December 2005 (manual screening) and the period from February 2006 to December 2006 (image-assisted screening). Squamous abnormalities included ASC-US; ASC, cannot rule out HSIL (ASC-H); low-grade squamous intraepithelial lesion (LSIL); HSIL; glandular abnormalities; and malignancies (squamous or glandular). In addition, the rates of HR-HPV-positive, HR-HPV-negative, and HR-HPV-quantity not sufficient were compared for the same periods. During both periods, testing for HR-HPV was performed only on ASC-US Pap tests. HR-HPV was tested with Digene Hybrid Capture 2 methodology. Productivity was calculated as the change in average slides screened per hour before and after imager implementation.

RESULTS

In total, 107,647 Pap tests were analyzed in the 2005 (54,438 Pap tests) and 2006 (53,209 Pap tests) timeframes. Increases in the detection of ASC-H, atypical glandular cells (AGC), LSIL, and HSIL were statistically significant. The proportion of negative for intraepithelial lesion or malignancy (NILM) and unsatisfactory cases decreased significantly with implementation of the TIS. The ASC to squamous intraepithelial lesion (ASC:SIL) ratio decreased from 1.5 to 1.0 after TIS implementation. Decreases in the ASC-US HR-HPV-positive proportion and increases in the ASC-US HR-HPV-negative proportion after implementation of the TIS were statistically significant. In our laboratory, a 60% increase in productivity was noted with use of the TIS.

CONCLUSIONS

Implementation of the TIS at BAMC significantly increased the detection of ASC-H, AGC, LSIL, and HSIL but had no significant impact on the ASC-US detection rate. Although the ASC-US rate did not change, both the HR-HPV-positive rate and the ASC:SIL ratio decreased. The data from the current study suggested that, at least initially, the use of imager-directed screening may increase the number of clinically insignificant ASC-US Pap tests.

The impact of digital imaging in the field of cytopathology

With the introduction of digital imaging, pathology is undergoing a digital transformation. In the field of cytology, digital images are being used for telecytology, automated screening of Pap test slides, training and education (e.g. online digital atlases), and proficiency testing. To date, there has been no systematic review on the impact of digital imaging on the practice of cytopathology. This article critically addresses the emerging role of computer-assisted screening and the application of digital imaging to the field of cytology, including telecytology, virtual microscopy, and the impact of online cytology resources. The role of novel diagnostic techniques like image cytometry is also reviewed.

Assuring the quality of quality assurance: seeding abnormal slides into the negative Papanicolaou smears that will be rapid rescreened

BACKGROUND

Rapid rescreening (RR) of negative Papanicolaou smears (PS) is used in many countries as a quality-assurance measure. Seeding of abnormal slides has been suggested as a way to increase the sensitivity of this procedure. Since 2004, the authors have carried out RR with seeding before issuing reports. In this article, they describe their experience.

METHODS

Abnormal seeds were sourced from the previous day's high-grade cases, both squamous and glandular. Slides were evaluated for the 'degree of difficulty' (which was defined as the number of fields required to find (fields-to-find [FTF]) the abnormality), relabeled, and redotted to make them indistinguishable from the routine RR work. The number of seeds found/missed, the identity of the screener, the type of seeded abnormality, the degree of difficulty of the seed, and the mapping technique used all were recorded. The cytologists also were surveyed about their views on seeding.

RESULTS

Overall, 14.8% of 3082 high-grade seeds were missed during RR. There was no relation between seeds missed and the mapping technique used. However, the difficulty of the seed was relevant to the number missed and ranged from 8.3% when the FTF was <5 to 36% when the FTF was >10 (P = .000). The difference between intraepithelial seeds and invasive seeds was significant for squamous seeds (P = .031) but not for glandular seeds. Glandular seeds also were more likely to be missed than squamous seeds (23.1% vs 14.3%; P = .002). Most cytologists believed that seeding was a good idea and that seeds increased their level of vigilance.

CONCLUSIONS

The authors' experience demonstrated that routine seeding is practicable for both conventional and liquid-based slides. With the advent of the human papillomavirus vaccine, abnormalities will become rarer, and seeding will be necessary to maintain the alertness of cytologists.

Automated screening versus manual screening: A comparison of the ThinPrep® imaging system and manual screening in a time study

The ThinPrep Imaging System (TIS) is an automated system that assists cytotechnologists in the primary screening of ThinPrep liquid based cervical samples. Between June 1, 2004, and April 1, 2005, four experienced cytotechnologists participated in the study in which the duration of the screening procedure was timed for each of the 11,354 slides included. In every slide 22 fields of view were reviewed, and the samples that contained potentially abnormal cells were fully screened. The screening time was reduced by 42% (mean) (p < 0.001). By manual rescreening of the negative TIS samples, abnormal cells were found in 10 samples (false negative rate 0.14%). In every case the abnormal cells had been identified by the scanner, but misinterpreted by the cytotechnologist. These findings stressed the importance of carefulness in the interpretation of the marked fields and beyond that helped the cytotechnologists and pathologists to have more confidence in the automated system.