Recommendations on Quality Control and Quality Assurance in Cervical Cytology

Quality and Performance of Papanicolaou Test using the Clinical and Laboratory Standards Institute (CLSI) EP12-A2 Guidelines: A Single-Center Study in Peru

Context

Quality assurance in cervical cytology is based on the cyto-histological correlation that is performed in several countries even without standardized protocols.

Aims

To evaluate the quality of the Pap smear with the Clinical and Laboratory Standards Institute (CLSI) EP12-A2 guideline in a Peruvian hospital.

Settings and Design

This prospective study was carried out at tertiary care national hospital.

Methods and Material

The 156 cyto-histological results were collected and coded according to the Bethesda 2014 and FIGO system. The evaluation with the CLSI EP12-A2 guide allowed estimating the performance and quality of the test.

Statistical Analysis Used

We performed a descriptive analysis of the cytological and histological data and correlation with the weight Kappa test. From the calculation of the likelihood ratios, the post-test probability was estimated using Bayes' theorem.

Results

In cytology, 57 (36.5%) were undetermined abnormalities, 34 (21.8%) low-grade squamous intraepithelial lesion (SIL), and 42 (26.9%) high-grade SIL. Of the total biopsies, 56 (36.9%) were cervical intraepithelial neoplasia (CIN) grade 1, 23 (14.7%) were both CIN grade 2 and 3. We determined sensitivity, specificity, a positive and negative predictive value of 94%, 74.6%, 58%, and 97.1%, respectively. We determined a moderate cyto-histological agreement (κ = 0.57). Atypical squamous cells of undetermined significance (40%), and cannot exclude high-grade squamous intraepithelial lesions (42.1%) that showed higher overdiagnosis results.

Conclusions

The quality and performance of the Papanicolaou test show high sensitivity and moderate specificity. The concordance found was moderate and the proportion of underdiagnosis was higher in abnormalities of undetermined significance.

Quality assurance in cytology reporting in Ghana: an urgent call

Introduction

In Ghana, the Papanicolaou (PAP) smear remains central to cervical cancer screening although human papilloma virus testing is recommended. The success of the PAP smear however depends on stringent quality processes. Unfortunately, PAP smear reporting in Ghana is uncoordinated with no clear quality guidelines.

Methods

We applied quality guidelines to all PAP smear diagnoses of high-grade squamous intraepithelial lesion (HSIL) at Catholic Hospital Battor from 1 June 2016 to 31 August 2021. Available slides were independently reviewed by two pathologists, colposcopy findings were correlated with PAP smear results and histology cytology correlation was carried out after loop electrosurgical excision procedure (LEEP).

Results

Of 17 women with HSIL, 3 available slides were reviewed and found to be normal (negative for intraepithelial lesion or malignancy), obviating the need for LEEP. Of the 11 that had LEEP after colposcopy, cytology histology correlation revealed that 54.6% (6) had no dysplasia, 27.3% (3) were cervical intraepithelial neoplasia (CIN) II and 18.2% (2) were CIN III. Cytology, colposcopy correlation showed that (out) of the 17 women, 52.9% (9) had no lesions, 29.4% (5) had minor changes and 17.7% (3) had major changes on their cervix. Of the nine that had no lesions on colposcopy, five had LEEP. Of these five, dysplasia (at least CIN II) was revealed in three (60%).

Conclusion

The lack of quality processes in PAP smear reporting results in a high false positive rate with overtreatment of patients. Quality measures need to be adopted for the reporting of PAP smears in Ghana if gains are to be made in the fight against cervical cancer.

Analytical and post analytical phase of an ISO 15189:2012 Certified cytopathology laboratory-a five year institutional experience

Objective:

Analytical and post analytical phase are integral part of total quality management system and include steps from submission of slides till reports are dispatched. The present study was conducted to analyze the analytical and post analytical phase of the ISO15189:2012 certified cytopathology laboratory. It was also intended to study the various errors which were encountered and steps taken to reduce these discrepancies.

Methods:

The study included all documents of quality program from 1 November 2014 till 31 Oct 2019 in medical institute situated in north Himalayan region of India. All the data was recorded and analyzed for analytical and post analytical phase.

Results:

The number of samples received in cytopathology lab was 21,566 with total quality errors of 5.19%. Out of these pre-analytical errors were 55%, analytical 10.5% and post analytical errors constituted 34.4%. The maximum errors detected were due to typographical errors followed by delayed turnaround time. Cyto-histopathological discordance was 10.5% in non-gynecological cases and 2.2% in gynecological cases.

Conclusion:

Analytical and post analytical phase analysis is essential to minimize the errors and improve the quality of cytopathology lab. Cyto-histopathological correlation is valuable for continuous data tracking in the cytopathology with analytical errors analysis. Maintenance of external, internal quality program, turnaround time with documentation, continuous training and communication with clinician is fundamental for quality improvement in any cytopathology lab. Acknowledgement of nonconformance with root cause analysis and sincere efforts to minimize them is the basic key for successful quality management.

A novel attention-guided convolutional network for the detection of abnormal cervical cells in cervical cancer screening

Early detection of abnormal cervical cells in cervical cancer screening increases the chances of timely treatment. But manual detection requires experienced pathologists and is time-consuming and error prone. Previously, some methods have been proposed for automated abnormal cervical cell detection, whose performance yet remained debatable. Here, we develop an attention feature pyramid network (AttFPN) for automatic abnormal cervical cell detection in cervical cytology images to assist pathologists to make a more accurate diagnosis. Our proposed method consists of two main components. First, an attention module mimicking the way pathologists reading a cervical cytology image. It learns what features to emphasize or suppress by refining extracted features effectively. Second, a multi-scale region-based feature fusion network guided by clinical knowledge to fuse the refined features for detecting abnormal cervical cells at different scales. The region proposals in the multi-scale network are designed according to the clinical knowledge about size and shape distribution of real abnormal cervical cells. Our method, trained and validated with 7030 annotated cervical cytology images, performs better than the state of art deep learning-based methods. The overall sensitivity, specificity, accuracy, and AUC of an independent testing dataset with 3970 cervical cytology images is 95.83%, 94.81%, 95.08% and 0.991, respectively, which is comparable to that of an experienced pathologist with 10 years of experience. Besides, we further validated our method on an external dataset with 110 cases and 35,013 images from a different organization, the case-level sensitivity, specificity, accuracy, and AUC is 91.30%, 90.62%, 90.91% and 0.934, respectively. Average diagnostic time of our method is 0.04s per image, which is much quicker than the average time of pathologists (14.83s per image). Thus, our AttFPN is effective and efficient in cervical cancer screening, and improvement of clinical workflows for the benefit of potential patients. Our code is available at https://github.com/cl2227619761/TCT_Detection.

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.

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.

Study of the Pre-Analytical Phase of an ISO 15189: 2012-Certified Cytopathology Laboratory: A 5-Year Institutional Experience

OBJECTIVE

Total quality management, which basically involves pre-analytical, analytical, and postanalytical phases, is relatively more difficult in cytopathology due to descriptive reports and subjective variability. The pre-analytical phase of total quality management constitutes a major burden of errors in the laboratory and it has not been widely studied in cytopathology except in cervical Pap smears. The present study was therefore conducted to study the pre-analytical phase over 5 years from April 2013 until May 2018 at an ISO 15189: 2012-certified cytopathology laboratory, in a resource-limited setting. It was also intended to study the level of satisfaction of the patients and the training of the professionals provided in the cytology lab so as to improve and maintain high quality standards.

METHODS

The study included all the documents relating to the quality program used in the last 5 years in a medical institute situated in the north sub-Himalayan region of India. All the data were recorded and analysed for pre-analytical analysis of the total quality management system.

RESULTS

In total, 20,130 samples were received for cytological investigation. The total number of errors which were detected in the cytopathology lab were 1,430, constituting 7.1% of the total investigations done. The pre-analytical phase errors comprised 57% of the total errors (815/1,430), analytical errors constituted 11% (157/1,430), while postanalytical errors represented 32% (458/1,430). Incompletely filled requisition forms constituted the most common pre-analytical error (38%). There was a gradual decrease in the errors with time, but with a sudden increase between January to June 2015 due to new technicians joining during that period.

CONCLUSION

Pre-analytical quality management is an essential component for maintaining the quality and reducing the errors in the cytopathology lab. Documentation, continuous training, and maintenance of internal and external quality control with quality charts are the key for successful quality management. The identification of non-conformance with root-cause analysis and provision of scope for continuous improvement is vital for quality improvement in the lab. Patient satisfaction is an important aspect of quality in the lab, which should be combined with the satisfaction of the personnel working in the lab.

Eco-Pap: The Ecological Modification of the Papanicolaou Stain for Sustainable Cervical Cancer Diagnosis

OBJECTIVES

To validate the ecological modification of the Papanicolaou stain (Eco-Pap) for the diagnosis of cervical cancer.

STUDY DESIGN

A prospective study was performed at the Mother and Child "San Bartolomé" Hospital, Lima, Peru. Reagent handling strategies were divided into three phases: we used (1) Harris progressive hematoxylin (for nuclear staining), (2) a polychromatic solution (a mix of EA-36/Orange G-6 to suppress the use of several alcohol baths), and (3) direct mounting (with Entellan® solution). The cellular details were analyzed by the staining quality index, an external quality control, and the Bethesda System 2014.

RESULTS

We evaluated 72,901 cervical smears stained with the Eco-Pap. The validation of the Eco-Pap against the conventional Pap stain was optimal (κ = 0.89; 95% CI: 0.87-0.92), showing a sensibility and specificity of 88.3% (95% CI: 85.1-90.0) and 98.7% (95% CI: 98-99.2), respectively. The Eco-Pap dramatically reduced the environmental pollution caused by 72 L of xylene, hydrochloric acid, and ammonia (6 L each) and mercury oxide.

CONCLUSION

The Eco-Pap is an innovative and efficient staining method reducing the use of toxic reagents with carcinogenic potential during cervical cancer screening by exfoliative cytology.

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.

Access to pathology and laboratory medicine services: a crucial gap

As global efforts accelerate to implement the Sustainable Development Goals and, in particular, universal health coverage, access to high-quality and timely pathology and laboratory medicine (PALM) services will be needed to support health-care systems that are tasked with achieving these goals. This access will be most challenging to achieve in low-income and middle-income countries (LMICs), which have a disproportionately large share of the global burden of disease but a disproportionately low share of global health-care resources, particularly PALM services. In this first in a Series of three papers on PALM in LMICs, we describe the crucial and central roles of PALM services in the accurate diagnosis and detection of disease, informing prognosis and guiding treatment, contributing to disease screening, public health surveillance and disease registries, and supporting medical-legal systems. We also describe how, even though data are sparse, these services are of both insufficient scope and inadequate quality to play their key role in health-care systems in LMICs. Lastly, we identify four key barriers to the provision of optimal PALM services in resource-limited settings: insufficient human resources or workforce capacity, inadequate education and training, inadequate infrastructure, and insufficient quality, standards, and accreditation.

Influence of Prior Knowledge of Human Papillomavirus Status on the Performance of Cytology Screening

OBJECTIVES

This study aimed to evaluate the influence of prior knowledge of human papillomavirus (HPV) status in cervical cytopathology readings.

METHODS

Participants comprised 2,376 women who underwent parallel cytology and HPV-DNA testing. Smears were read twice by the same team, first with previous knowledge of HPV-DNA status.

RESULTS

Overall, 239 (10.2%) smears had their cytology classification altered by the HPV-informed review. Cytology readings with prior knowledge of the HPV status revealed 10.5% of abnormal smears (atypical squamous cells of undetermined significance or higher), while without prior knowledge, this rate dropped to 7.6%. When HPV status was informed, a significant increase in all categories of altered smears was observed. Cytology with prior knowledge of HPV status detected more cervical intraepithelial neoplasia grade 2 or higher (CIN 2+) compared with blinded: 86.7% vs 60.0%.

CONCLUSIONS

Our data indicate that cytology interpreted with prior knowledge of the HPV status provides higher sensitivity for CIN 2+ lesions while marginally reducing the overall specificity compared with HPV status blinded cytology.

Conventional Microscopical versus Digital Whole-Slide Imaging-Based Diagnosis of Thin-Layer Cervical Specimens: A Validation Study

BACKGROUND

Whole-slide imaging (WSI) has been implemented in many areas of pathology, but primary diagnostics of cytological specimens are lagging behind. One of the objectives of viewing scanned whole-slide images from histological or cytological specimens is remote exchange of knowledge and expertise of professionals to increase diagnostic accuracy. We compared the scoring results of our team obtained in double readings of two different data sets: conventional light microscopy (CLM) versus CLM and CLM versus WSI. We hypothesized that WSI is noninferior to CLM for primary diagnostics of thin-layer cervical slides.

MATERIALS AND METHODS

First, we determined the concordance rate at different thresholds of the participating cytotechnicians by double reading with CLM of 500 thin-layer cervical slides (Cohort 1). Next, CLM was compared with WSI examination of another 505 thin-layer cervical slides (Cohort 2) scanned at ×20 in single focus plane. Finally, all major discordant cases of Cohort 1 were evaluated by an external expert in the field of gynecological cytology and of Cohort 2 in the weekly case meetings.

RESULTS

The overall concordance rate of Cohort 1 (CLM vs. CLM) was 97.8% (95% confidence interval [CI]: 96.0%-98.7%) and of Cohort 2 was 95.3% (95% CI: 93.0%-96.9%).

CONCLUSION

Concordance rates of WSI versus CLM were comparable with those of CLM versus CLM. We have made a step forward paving the road to implementation of WSI also in routine diagnostic cytology.

Team Reading (Peer Review) of Suspicious/Positive Slides for Continuous Quality Improvement in Cervical-Vaginal Cytology: A Comparison between Methods and Indicators

AIM

In 2013, the Local Health Unit Roma 2 ex C screening laboratory introduced a new set of indicators for quality assurance. We compare 2 sets of indicators based on routine multiple readings (peer review) for their ability to identify problems in single-reader accuracy.

METHODS

All suspect slides were blindly reviewed by all the cytologists of the laboratory. The standard set of indicators includes interreader Cohen's kappa, positivity rate and atypical squamous cell of undetermined significance/squamous intraepithelial lesion (ASC-US/SIL) ratio. The new set included sensitivity for cervical intraepithelial neoplasia of grade 2 or worse (CIN2+), positive predictive value (PPV) and percentage of positive high-risk (HR)-HPV cases among ASC-US. In order to estimate sensitivity and PPV, we considered all women for whom there was a consensus of negative cytology, negative HR-HPV test, negative colposcopy or negative histology true negative.

RESULTS

Kappa values ranged from 0.521 to 0.753, with narrow 95% confidence intervals (CIs). Positivity rate ranged from 73.9 to 85.7 and the ASC-US/SIL ratio from 0.61 to 0.81. Sensitivity for CIN2+ at the low-grade SIL threshold ranged from 85.8 to 94.2, PPV ranged from 14.8 to 19.4, and both had a broad 95% CI. Readers with low sensitivity did not show low kappa values. The percentage proportion of HR-HPV-positives (HR-HPV+) among ASC-US ranged from 39.9 to 43.8% with a narrow 95% CI.

CONCLUSION

The proportion of HR-HPV+ among ASC-US cases is a powerful indicator to address in training.