Quality assurance and risk reduction guidelines

A Hierarchical Feature-Based Methodology to Perform Cervical Cancer Classification

Prevention of cervical cancer could be performed using Pap smear image analysis. This test screens pre-neoplastic changes in the cervical epithelial cells; accurate screening can reduce deaths caused by the disease. Pap smear test analysis is exhaustive and repetitive work performed visually by a cytopathologist. This article proposes a workload-reducing algorithm for cervical cancer detection based on analysis of cell nuclei features within Pap smear images. We investigate eight traditional machine learning methods to perform a hierarchical classification. We propose a hierarchical classification methodology for computer-aided screening of cell lesions, which can recommend fields of view from the microscopy image based on the nuclei detection of cervical cells. We evaluate the performance of several algorithms against the Herlev and CRIC databases, using a varying number of classes during image classification. Results indicate that the hierarchical classification performed best when using Random Forest as the key classifier, particularly when compared with decision trees, k-NN, and the Ridge methods.

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.

Inadequate clinical data on Pap test request form: Where are we headed in the era of precision medicine?

The request form accompanying any sample to a clinical laboratory constitutes an important communication tool between the clinician and the laboratory personnel. Much has been written about the inadequacy of pertinent clinical data on the request slips for hematology and biochemistry tests and its impact on the subsequent test interpretation and error liability. Although the cytology laboratories, including those performing cervical cytology, have to deal with a similar problem of lack of clinical information critical to the proper interpretation of cytomorphologic features, the issue has not been attended to or reported adequately in the literature. This article attempts to explore this topic of inadequate clinical data on Pap test request form from multiple perspectives and suggest possible ways to circumvent this age-old problem. These recommendations may be tailor-made and adopted as per the individual laboratory’s logistics.

Performance of Laboratories after 10 Years of Participating in External Quality Monitoring in Cervical Cytology

OBJECTIVE

To evaluate the performance of laboratories accredited by the National Health System that perform cytopathology examination of the uterine cervix after 10 years of participation in external quality monitoring (eQM).

STUDY DESIGN

Seven laboratories were assessed in this study. To assess the concordance of the representation of epithelia and results, 6,536 examinations (3,433 in 2007 and 3,103 in 2017) were reviewed. Statistical analysis was performed using the κ coefficient as well as the χ2 and the Fisher exact test (p < 0.05).

RESULTS

All laboratories showed adequate infrastructure and internal quality monitoring. Regarding the representation of the epithelia, the concordance remained excellent (κ between 0.84 and 0.94). In 2007, 26 false-negative results (FN), 157 false-positive results (FP), and 79 delays in clinical conduct (DCC) were identified (κ = 0.80). In 2017, 24 FN, 42 FP, and 38 DCC were identified (κ = 0.90). Five laboratories showed improvement in concordance from 2007 to 2017. We observed significant improvement in cytomorphological criteria of the results: atypical squamous cells of undetermined significance (p < 0.001), atypical squamous cells cannot exclude high-grade squamous intraepithelial lesion (p < 0.016), and low-grade squamous intraepithelial lesion (p < 0.001). We also observed a considerable improvement in the results of cellular abnormalities in glandular epithelium (p < 0.0504).

CONCLUSIONS

Ten years after the implementation of eQM, improvements in the concordance of results were observed as well as reductions in FN, FP, and DCC in all laboratories monitored.

Recommendations on Quality Control and Quality Assurance in Cervical Cytology

OBJECTIVE

We aimed to critically evaluate the importance of quality control (QC) and quality assurance (QA) strategies in the routine work of uterine cervix cytology.

STUDY DESIGN

We revised all the main principles of QC and QA that are already being implemented worldwide and then discussed the positive aspects and limitations of these as well as proposing alternatives when pertinent.

RESULTS

A literature review was introduced after highlighting the main historical revisions, and then a critical evaluation of the principal innovations in screening programmes was conducted, with recommendations being postulated.

CONCLUSIONS

Based on the analysed data, QC and QA are two essential arms that support the quality of a screening programme.

General Quality Practices in Gynecologic Cytopathology: Findings From the College of American Pathologists Gynecologic Cytopathology Quality Consensus Conference Working Group 3

Context.—There are many long-standing quality monitors for cytopathology laboratories and their cytotechnologists and pathologists. Many of these monitors are based on tradition and empirical good intentions. There is no established standard as to how results of these monitors should be used in a quality assurance program.

Objective.—To review practices that are typically part of a general quality program in cytopathology laboratories and to provide statements regarding good laboratory practices that laboratories may find useful in a quality assurance program in their own setting.

Data Sources.—An expert working group evaluated results from a national laboratory survey, responses from follow-up questions posted on a Web site, and findings from the literature. The group created statements on good laboratory practices related to general quality practices and quality assurance in gynecologic cytopathology. These were discussed and voted on at a consensus conference.

Conclusions.—Laboratories follow many metrics. Most laboratories facilitate comparison of individual metrics against the laboratory's metrics: 81.1% for cytotechnologists and 59.6% for pathologists. The majority of laboratories facilitate comparison of individual cytotechnologist metrics with other cytotechnologists, but less frequently metrics from pathologists with other individuals. The most common methods to recognize variance in performance in individuals were by identifying outliers from the data or by user-defined action limits. The most common method to address variance was an attempt to identify the cause of the variance and conduct a focused review. Quality metrics should be monitored for the laboratory as a whole and in selected cases for both individual pathologists and cytotechnologists. Results should be shared with individuals, and newly hired primary screeners should be monitored. Reviewing selected cases is a useful quality tool. Low-volume methodologies, such as conventional Papanicolaou tests, should have additional oversight.

European guidelines for quality assurance in cervical cancer screening: recommendations for cytology laboratories

The quality of a cervical cytology laboratory depends on adequate handling and staining of the samples, screening and interpretation of the slides and reporting of the results. These guidelines give an overview of procedures recommended in Europe to manage the balance between best patient care possible, laboratory quality assurance and cost effectiveness and will be published as a chapter 4 in the European Guidelines for Quality Assurance in Cervical Cancer Screening. The laboratory guidelines include protocols for personnel and organisation, material requirements, handling and analysing cervical samples, recording of results, quality management and communication. The section on quality management is comprehensive and includes protocols for all aspects of internal and external quality assurance. The guidelines are extensively referenced and as far as possible the recommendations are evidence-based.

Evaluation of 100% rapid rescreening of negative cervical smears as a quality assurance measure

OBJECTIVE

The objective of this study was to compare the performance of 100% rapid rescreening, 10% random rescreening and the review of smears selected on the basis of clinical criteria, as a method of internal quality control of cervical smears classified as negative during routine screening.

METHODS

A total of 3149 smears were analysed, 173 of which were classified as positive and 2887 as negative, while 89 smears were considered unsatisfactory. The smears classified as negative were submitted to 100% rapid rescreening, 10% random rescreening, and rescreening based on clinical criteria. The rescreening stages were blinded and results were classified according to the Bethesda 2001 terminology. Six cytologists participated in this study, two of whom were responsible for routine screening while the other four alternated in carrying out rescreening so that no individual reviewed the same slide more than once.

RESULTS

The 100% rapid rescreening method identified 92 suspect smears, of which 42 were considered positive at final diagnosis. Of the 289 smears submitted to the 10% rescreening method, four were considered abnormal but only one was confirmed positive in the final diagnosis. Of the 690 smears rescreened on the basis of clinical criteria, 10 were considered abnormal and eight received a positive final diagnosis.

CONCLUSIONS

The 100% rapid rescreening method is more efficient at detecting false-negative results than 10% random rescreening or rescreening on the basis of clinical criteria, and is recommended as an internal quality control method.

Quality assurance in cervical screening of a high risk population: a study of 65,753 reviewed cases in Parana Screening Program, Brazil

Epidemiological data from the Quality Assurance Unit (QAU) of the Cervical Cancer Screening Program of Paraná is discussed. Slides (65,753) reviewed by the QAU, from October 1997 to July 1999, were analyzed. Relations between agreement rate, diagnostic categories, and age groups were tested. The overall agreement rate was 97.04% (kappa +/- 95%, confidence interval = 0.888 +/- 0.003). Low-grade squamous intraepithelial lesion (LSIL) showed its peak prevalence in patients < or = 19 yr (8.3%). High-grade squamous intraepithelial lesion (HSIL) was more common in women between 40 and 49 yr (5.0%). Squamous-cell carcinoma (SCC) was almost exclusively seen in women > or = 40 yr. The lowest agreement rates were seen in adenocarcinoma (54.5%; kappa = 0.667) and LSIL cases (76.3%, kappa = 0.822), and in women < or = 19 yr (95.8%). It was concluded that constant monitoring to assess specific errors allows directed measures. The 10% rescreening model of quality assurance proved to be effective in a low resources setting with a positive overall financial impact.

Bethesda 2001 implementation and reporting rates: 2003 practices of participants in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology

CONTEXT

The 2001 Bethesda System for the reporting of cervical cytology specimens and the use of new liquid-based and human papillomavirus testing technologies have led to changes in cervical cytology reporting practices.

OBJECTIVES

To analyze current laboratory reporting practices using Bethesda 2001 terminology and to compare results with previous survey data from 1996.

DESIGN

Questionnaire survey mailed to 1751 laboratories in mid-2003.

PARTICIPANTS

Laboratories enrolled in the College of American Pathologists Interlaboratory Comparison Program in Cervicovaginal Cytology.

RESULTS

Of the 759 responding laboratories, most (85.5%) had implemented Bethesda 2001 terminology, and the majority had adopted major changes, such as elimination of the benign cellular changes category and the satisfactory but limited category. The median reporting rate for low-grade squamous intraepithelial lesion was 2.1%, compared to a 1996 median rate of 1.6%, but the increase was confined to liquid-based preparations. Reporting rates for high-grade squamous intraepithelial lesion (median, 0.5%) and atypical squamous cells (ASC) had changed little. Most ASC cases were subclassified as "undetermined significance" (median, 3.9%) with ASC, cannot exclude high-grade SIL accounting for a minority (median, 0.2%). The median ratio of ASC to squamous intraepithelial lesions and carcinomas (SIL+) was 1.4 and was lower than the 1996 median ratio of 2.0. Median reporting rates for squamous abnormalities for 2002 were noted to be significantly higher for liquid-based preparations than for conventional smears, while median ASC/SIL+ ratios were lower. Most laboratories offer human papillomavirus testing, but almost half (47%) of laboratories do not know the percentage of positive testing results in patients with ASC.

CONCLUSIONS

Most laboratories have implemented Bethesda 2001 terminology. New criteria and liquid-based methods have led to an increase in low-grade squamous intraepithelial lesion reporting rates and a decrease in ASC/ SIL+ ratios when compared with 1996 data. Liquid-based preparations have higher median squamous intraepithelial lesion rates and lower ASC/SIL+ ratios than conventional smears.

Metaanalysis of the accuracy of rapid prescreening relative to full screening of pap smears

BACKGROUND

Efficient quality assurance and improvement measures are essential ingredients in a well organized cytology-based program for cervical carcinoma screening. Various pap smear review procedures, aiming for optimization of accuracy, are described throughout the literature. Evaluation and synthesis of those methods are needed. In a previous study, we pooled data on the diagnostic quality of rapid reviewing (RR) of cervical smears initially reported as normal or unsatisfactory. We now focus on rapid prescreening (RPS) of unreported smears.

METHODS

Six published studies on the accuracy of RPS relative to subsequent full screening were pooled using metaanalytic methods. Individual and pooled sensitivity, specificity, and predictive values were assessed using forest plots. Random effect pooling methods were used for interstudy heterogeneity. Variation in sensitivity according to influencing factors was explored by metaregression.

RESULTS

The pooled average sensitivity of RPS was 64.9% (95% confidence interval [CI] 50.7-79.1%) for all abnormalities, 72.6% (95% CI 60.6-85.2%) for low-grade lesions or more severe, and 85.7% (95% CI 77.8-93.6%) for high-grade lesions or more severe. The pooled specificity was estimated at 96.8% (CI 95.8-97.8%). The sensitivity increased significantly with duration of screening and decreased with workload. Almost 3% of all abnormal slides were detected only by RPS (2.8%; CI 0.0-5.8%). This is comparable to the proportion of false-negative smears detectable by RR.

CONCLUSIONS

Rapid prescreening has a high yield for severe dysplasia and shows diagnostic properties that support its use as a quality control procedure in cytologic laboratories. We showed previously that RR is superior to full reviewing of a 10% random sample of negative slides (10% FR). Because the yield of additional abnormalities found by RR and RPS is comparable, we expect RPS to be more efficient than 10% FR as well.

Accuracy of reporting endocervical component adequacy--a continuous quality improvement project

Inaccurate reporting of the absence of an endocervical (EC) component on Pap smears often results in slide rescreens, amended reports, clinician dissatisfaction, and sometimes unnecessary repeat smears. Therefore, the accuracy of reporting EC component adequacy was selected as a quality indicator for the laboratory continuous quality improvement program (CQI). The process consisted of problem identification, analysis of the situation, collection of data, implementation of solutions, and evaluation of results. The objective of the study was to determine if the accuracy of reporting EC component adequacy on Pap smears improved after application of such a program. During the first phase, 150 Pap smears originally reported with the absence of an adequate EC component and 150 smears reported with the presence of an adequate EC component were rescreened to measure the baseline accuracy of EC component adequacy reporting. The improvement process was then implemented. A cause-and-effect diagram was developed and root cause was determined. A presentation was then made to the cytology staff. Criteria for EC component adequacy were reviewed, examples were shown, and standardized marking of EC component was implemented. Following improvement actions, a second audit of 150 Pap smears reported with the absence of an adequate EC component as well as 150 smears reported with the presence of an adequate EC component was undertaken to measure change in performance in assessing EC component adequacy. For the baseline rescreening, before initiation of the CQI program, 98% accuracy was achieved with smears that were reported as adequate for EC component present. However, the accuracy with smears reported as absence of an adequate EC component was only 71%, i.e., an adequate EC component was identified in almost 1/3 of these cases on rescreen. After the implementation of improvement actions, the accuracy with smears reported with the presence of EC component remained high (98%) and the accuracy of reporting the absence of EC component was 90%. The difference of the latter before and after the implementation was statistically significant (P = 0.015, z-test). The accuracy of reporting EC component adequacy increased following the CQI process. Using reporting EC component adequacy as an example, we demonstrate that by treating clinical problems as quality control issues and applying basic quality improvement tools, a positive outcome can be effected.

[Cell anomalies in the cervix and subsequent pre-cancerous lesions in a Health Area]

OBJECTIVE

To determine the frequency of epithelial anomalies in cervical smears during the three years from August 1997 to July 2000 and of subsequent pre-cancerous lesions that are histologically confirmed, with differentiation also being made between health care levels.

DESIGN

Retrospective descriptive study.

SETTING

Anatomy Pathology referral Laboratory. Talavera de la Reina Health Area.

PARTICIPANTS

5,712 cervical smears and 70 biopsies.Intervention. Review of path reports.

MAIN MEASUREMENTS AND RESULTS

308 (5.4%) smears showed anomalies that were not attributed to a benign process. 209 (68%) of these were followed up, 139 (45%) of them through repetition of the smear and 70 (23%) through biopsy. Cell and cytology correlated in 42 women (30.2%), and cell-histology in 27 (38.6%) (0.47%, n = 5,712). 2,874 of the smears in the Area were taken in Primary Care, and 127 (22.2%) cell anomalies and 6 (0.1%) pre-cancerous lesions were found at this health care level.

CONCLUSIONS

The 5.4% frequency of anomalies is consistent with that in other population groups with an incidence of cervical cancer similar to ours. The 0.47% pre-cancerous lesions confirmed histologically is very low in comparison with the anomalies, which suggests that this intervention needs to be improved. This could be done by increasing biopsies for cell anomalies and screening of women at risk. Interpretation of smear reports, more information to the women and follow-up of the findings could all be improved, too.

Cervical biopsy/cytology correlation data can be collected prospectively and shared clinically

Cervical cytology (Cy) and biopsy (Bx) correlation is used by institutions for the evaluation of their cytodiagnostic capabilities as a part of overall laboratory quality improvement (QI). However, the data obtained from correlation are not routinely included in most surgical pathology (SP) reports. Our laboratory's procedure is to include the correlation of the patient's previous (most recent) cytology smear in the surgical pathology report of all/any gynecologic surgical pathology specimens. We reviewed this process for the time period between July 1998-June 1999. Any noncorrelating cases were assigned a correlation review code by the reviewing cytopathologist: major Cy diagnostic error (DE1), minor Cy diagnostic error (DE2), Cy sampling error (Cy SE), or biopsy sampling error (Bx SE). Of 3,486 cases reviewed, 3,229 cases were satisfactory for correlation studies. Concordant results were found in 86.9%. Cy DE1 due to either Cy screening or interpretation errors or both were found in 0.2% (n = 7) of all cases, while Cy DE2 due to the same were found in 1% (n = 32). Bx SE accounted for discrepancies in 6.8% (n = 220) of all cases, while 5.1% (n = 164) of the total cases were discrepancies due to Cy SE. Follow-up Bx was available in 97.2% (n = 214) of the Bx SE, and showed 16.4% (n = 35) to be major discrepancies and 83.6% (n = 179) to be minor discrepancies. Cervical Cy/Bx correlation is useful for the evaluation of a laboratory's QI. It is also useful for the identification of either Cy or Bx SE. While QI data exist as "internal use only" documents, SE data (as part of the CC (correlation comment) included in SP reports) are vital to a specific/given patient. Bx SE was identified in 6.3% of our patients, indicating a possible need for rebiopsy. This type of QI data may be shared clinically, and may direct the management for maximum diagnostic and patient benefit.

An analysis of factors that influence the ASCUS/SIL ratio of pathologists

In pursuit of physician-specific performance data in cytology, we have been calculating the ASCUS/SIL (atypical squamous cells of undetermined significance/squamous intraepithelial lesion) ratio of cytopathologists (CPs) and providing confidential feedback every 6 months. At the same time, thin-layer technology was introduced as an alternative to conventional smears. Thus we analyzed factors that may influence the ASCUS/SIL ratio, particularly the effect of periodic feedback on outliers (defined by a professional benchmark). For 3 years, the mean ASCUS/SIL ratio for all CPs decreased significantly from 2.92 to 1.87. There was great variability in the mean ASCUS/SIL ratio among 12 CPs (range, 1.11-5.89). Of the 6 CPs who worked continuously during this time, 2 showed a statistically significant decrease in their ASCUS/SIL ratio, including the CP with the highest ratio; 1 showed a significant increase. The mean ASCUS/SIL ratio did not correlate well with years of CP experience or with individual annual case volume. The ASCUS/SIL ratio of some CPs can decrease significantly over time. Whether it was due to feedback or the introduction of thin-layer preparations could not be determined.