Internal quality control for cervical cytopathology: comparison of potential false-negatives detected at rapid prescreening and at 100% rapid review

Liquid-Based Screening Tests Results: HPV, Liquid-Based Cytology, and P16/Ki67 Dual-Staining in Private-Based Opportunistic Cervical Cancer Screening

The baseline data from the private-based opportunistic cervical cancer screening with HRHPV14, liquid-based cytology (LBC) and p16/Ki67 testing, and its quality assessment/quality control (QA/QC) tools are lacking. The age-stratified analysis of 30,066 screening tests results in a Polish population, including the investigation of HRHPV14 status, LBC, and p16/Ki67 dual-staining reporting rates, along with immediate histopathologic correlations, was conducted. For cytopathologic QA/QC, the College of American Pathologists (CAP) benchmarks and enhanced safety protocol were used. The NILM/ASC-US/LSIL/ASC-H/HSIL/AGC reporting rates were 93.9/3.4/2.0/0.22/0.24/0.11, respectively, with correlating HRHPV14-positive rates of 8.4/48.9/77.2/84.6/90.7/26.7. The reporting rates for HSIL (CIN2+) in HRHPV-positive women with NILM/ASC-US/LSIL/ASC-H/HSIL/AGC referred for a colposcopy with biopsy were 19.1/25.8/22.5/12.4/19.1/1.1% of the total HSIL (CIN2+). In total, of the 1130 p16/Ki67 tests, 30% were positive. In NILM HRHPV14-positive women with available histology result, HSIL(CIN2+) was detected in 28.3% of cases. In the first such large-scale Polish study presenting HRHPV14, informed LBC and HSIL (CIN2+) results, the reporting rates were highly consistent with data from American and other CAP-certified laboratories, confirming the possibility of using the 2019 ASCCP risk-based guidelines as one of the screening strategies outside of the US, in conditions of proper QA/QC. The private-based screening model can be effective in cervical cancer prevention, particularly in countries with low population coverage of public funds-based systems.

Sample Adequacy Control (SAC) Lowers False Negatives and Increases the Quality of Screening: Introduction of "Non-Competitive" SAC for qPCR Assays

Sample Adequacy Control (SAC) has critical analytical, clinical and epidemiological value that increases confidence in a negative test result. The SAC is an integral qPCR assay control, which ensures that all pre-analytical and analytical steps are adequate for accurate testing and reporting. As such, a negative SAC with a negative result on pathogen screen specifies that the result should be reported as inconclusive instead of negative. Despite this, many regulatory approved tests do not incorporate SAC into their assay design. Herein, we emphasize the universal value of SAC and offer for the first time, a simple technical strategy to introduce non-competitive SAC which does not interfere with the limit of detection for the screened pathogen. Integration of SAC can provide key benefits towards identifying, isolating, quarantining and contact tracing infected individuals and in turn can improve worldwide efforts in infection control.

Cric searchable image database as a public platform for conventional pap smear cytology data

Amidst the current health crisis and social distancing, telemedicine has become an important part of mainstream of healthcare, and building and deploying computational tools to support screening more efficiently is an increasing medical priority. The early identification of cervical cancer precursor lesions by Pap smear test can identify candidates for subsequent treatment. However, one of the main challenges is the accuracy of the conventional method, often subject to high rates of false negative. While machine learning has been highlighted to reduce the limitations of the test, the absence of high-quality curated datasets has prevented strategies development to improve cervical cancer screening. The Center for Recognition and Inspection of Cells (CRIC) platform enables the creation of CRIC Cervix collection, currently with 400 images (1,376 × 1,020 pixels) curated from conventional Pap smears, with manual classification of 11,534 cells. This collection has the potential to advance current efforts in training and testing machine learning algorithms for the automation of tasks as part of the cytopathological analysis in the routine work of laboratories.

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.

Benefit of double-reading cytology smears as a triage strategy among high-risk human papillomavirus-positive women in Mexico

BACKGROUND

The goal of this study was to determine whether the detection of histologically confirmed cases of cervical high-grade squamous intraepithelial lesions or worse (HSIL+) can be increased by having each liquid-based cytology (LBC) slide read by 2 cytotechnologists as part of routine screening.

METHODS

Over 36,212 women aged 30 to 64 years participated in the Forwarding Research for Improved Detection and Access for Cervical Cancer Screening and Triage (FRIDA) Study in Mexico between 2013 and 2016. For each participant, 2 cervical samples were collected at the same clinic visit, one to test for high-risk human papillomavirus (hrHPV) and the other for LBC, which was used to triage those with a hrHPV positive result. LBC slides were evaluated by 7 cytotechnologists, with each slide read independently by 2 blinded cytotechnologists. All women with atypical cells of undetermined significance or a worse result were referred to colposcopy for further evaluation and diagnosis. Three pathologists evaluated the biopsy specimens to confirm the final HSIL+ diagnosis. The HSIL+ detection rates for the single versus double reading were estimated and compared.

RESULTS

A total of 3,914 women with a positive hrHPV result were triaged with LBC. The first and second cytology readings resulted in 43 HSIL+ cases detected; the double-reading strategy detected 9 additional HSIL+ cases, resulting in a total of 52 HSIL+ cases. The HSIL+ detection rate increased from 10.99/1000 with a single reading to 13.29/1000 with the double-reading strategy (P = .004).

CONCLUSION

A 20.9% increase in HSIL+ cases detected was achieved with a double reading of the LBC slides in this sample of hrHPV-positive women.

Performance of rapid prescreening and 100% rapid review as internal quality control methods for cervical cytopathology

BACKGROUND

An objective of quality control for cervical cytopathology is reducing high rates of false-negative results of laboratory tests. Therefore, methods to review smears such as rapid prescreening and 100% rapid review, which have shown better performance detecting false-negative results, have been widely used. The performance of rapid prescreening and the performance of 100% rapid review as internal quality control methods for cervical cytology examinations were evaluated.

METHODS

For 24 months, 9318 conventional cervical cytology smears underwent rapid prescreening and routine screening. The 100% rapid review method was performed for 8244 smears classified as negative during routine screening. Any discordant results underwent detailed review to define the final diagnosis. This was considered the gold standard for evaluating the performance of rapid prescreening and 100% rapid review.

RESULTS

Routine screening showed increases of 13.3% and 11.5% in the detection of abnormal smears with rapid prescreening and 100% rapid review, respectively. The relative percentage variation showed a 38.1% increase in the diagnosis of atypical squamous cells of undetermined significance with routine screening and rapid prescreening and a 12.5% increase in the diagnosis of atypical squamous cells, cannot exclude high-grade squamous intraepithelial lesion with both rapid prescreening and 100% rapid review. Sensitivity rates of rapid prescreening and routine screening were 48.2% and 83.2%, respectively. Sensitivity rates of rapid prescreening and 100% rapid review were 65.7% and 57.8%, respectively, for detecting false-negative results.

CONCLUSIONS

Inclusion of rapid prescreening and/or 100% rapid review improved the diagnostic sensitivity of the cervical cytology examination and reduced false-negative results of routine screening and can provide good quality control.

Does 100% Rapid Review Improve Cervical Cancer Screening?

OBJECTIVE

The aim of this work was to evaluate 100% rapid review (100% RR) as a useful tool to detect false negative (FN) results.

STUDY DESIGN

A sample of 8,677 swabs was investigated; the unsatisfactory and negative results were referred to 100% RR, concordant results were taken as the final diagnosis, while the discordant results were debated in a consensus meeting to reach a conclusion. The positive results were examined by 2 cytologists. The data were entered into SAS statistical software, and the agreement of the 100% RR results with the final diagnosis was tested with the weighted kappa statistic.

RESULTS

There was a significant increase in unsatisfactory results from 348 to 1,927, and of positive results from 174 to 349. On the other hand, there was a substantial decrease in negative results from 8,155 to 6,401. Assessing the relative risk of FN results in smears that were not referred to quality control (100% RR) revealed the following results: atypical squamous cells of undetermined significance (ASC-US), 2.93; low-grade squamous intraepithelial lesion (LSIL), 2.72; high-grade squamous intraepithelial lesion/atypical squamous cells - cannot exclude HSIL (HSIL/ASC-H), 2.25. Evaluating by age group, a higher risk for LSIL (4.90) and ASC-US (3.85) was observed in patients aged under 25 years, whereas patients between 25 and 64 years and those over 64 years presented a higher risk for HSIL and ASC-H: 2.46 and 2.75, respectively.

CONCLUSION

100% RR is an effective screening tool for FN results in countries where molecular tests for DNA-HPV and prophylactic vaccines are not available in cervical cancer screening programs.

Exploring avenues for best use of cytotechnologists in non-gynaecological cytology: Double screening or independent sign-out

OBJECTIVE

Cytotechnologist (CT) screening workload has been decreasing due to the falling number of Papanicolaou tests. This continuing trend has prompted exploration of ways to best employ the CT skillset. One potential way of more effective use is by having two CTs double screen non-gynaecological (NGC) cases to assess whether this improves screening quality and concordance with pathologists. Another is evaluating the CT's performance on low-complexity negative NGC cases for a potential independent CT sign-out without pathologist review.

METHODS

In total, 1119 NGC cases were reviewed; 577 screened by two CTs and 542 screened by one CT. All cases were signed out by a pathologist and all CT interpretations were compared to the pathologist final diagnoses. The disagreements were classified based on degree of discrepancy. The extra workload by adding the second screener was assessed.

RESULTS

The agreement rate between the CT's screening interpretation and pathologist's interpretation did not improve by adding a second CT compared to a single screener (91.5% vs 92.9%, respectively). CT to pathologist concordance was very high on low complexity NGC cases (voided urine, fluid, sputum) whether screened and interpreted as negative by one CT (97.3%) or two CTs (99.3%).

CONCLUSION

Double screening of NGC cases by two cytotechnologists prior to pathologist sign-out does not improve screening quality and is not cost-effective. The high concordance between the CTs and pathologists in this limited group of low complexity negative cases suggests that such cases could be signed out independently by cytotechnologists.