Comparison of Unsatisfactory Samples from Conventional Smear versus Liquid-Based Cytology in Uterine Cervical Cancer Screening Test

Evaluation of a Novel Fixative Solution for Liquid-Based Cytology in Diagnostic Cytopathology

Since its introduction in the early 2000s, liquid-based cytology (LBC) has been increasingly used for gynecologic and non-gynecologic cytology, and its multiple advantages have been widely recognized. The aim of this study was to investigate the use of a new fixative and pre-analytical method for morphological diagnosis in cytological samples. In particular, we evaluated the effect of a novel preservative solution on the preparation of diagnostic slides by comparing it with the standard reference used globally in cytology laboratories. This study included both gynecological (n = 139) and non-gynecological (n = 183) samples. Several morphologic variables were then identified and evaluated. Using this approach, we were then able to demonstrate the suitability of the new system, with improved safety, to be integrated within current pathology clinical practice. Overall, using a safer preservative solution, the study shows no statistical difference (and then non-inferiority) in the new fixation protocol compared with the standard reference used in routine practice in terms of diagnostic adequacy, evaluated both in clinically relevant gyn and non-gyn datasets.

The Role of p16/Ki67 Dual Staining in Cervical Cancer Screening

Cervical cancer screening has enabled a decrease in the incidence and mortality of cervical cancer. Various screening modalities have been studied to date. In many countries, screening is still based on cervical cytology, where cervical cells obtained either on glass or in a liquid medium are examined under a microscope. However, the fact that the vast majority of cervical cancers are a result of persistent infection with high-risk human papillomaviruses (hr-HPV) has led to the implementation of primary HPV screening in many countries. Taking into consideration the fact that the majority of HPV infections are transient and do not cause cervical precancer, effective triage methods are needed to prevent an increase in colposcopy referrals. Among these, the most extensively investigated are HPV genotyping, HPV methylation, and p16/Ki67 dual staining. In this manuscript, we briefly summarize the current knowledge regarding different screening strategies for the prevention of cervical cancer, with a focus on p16/Ki67 dual staining. In addition, we provide an explanation regarding the rationale for the use of various screening modalities based on the molecular biology of cervical cancer and cervical precancerous lesions.

The possibilities of adapting the re-processing protocol in the practice of the ThinPrep Pap test

The method of liquid cytology is a newer diagnostic test compared to the traditional cytological examination of scrapings from the cervix and allows you to standardize morphological examination and reduce the number of unsatisfactory samples. One of the factors determining the adequacy of the Pap test is the number of squamous epithelial cells in the sample. The abundance of blood elements, mucus, lubricant or inflammatory elements may affect the information content of the sample. In the practice of the ThinPrep Pap test, in the case of receiving an inadequate sample, a protocol for re-processing the contents of the vial is used in order to neutralize the possible influence of such impurities on the final result. This work contains an overview of the methods of application of the protocol of re-processing and their own experience of adapting the protocol in the practice of the clinical diagnostic laboratory.

Liquid-Based Cytology in the Detection of Premalignant Lesions in Patients with "Atypia in Squamous Cells" in Conventional Cytology

Background

The management of patients with "Atypical Squamous Cells" (ASC) in conventional papanicolaou smears (CPS) is based on the risk of high-grade squamous intraepithelial lesion (HSIL). The efficacy of liquid-based cytology (LBC) to detect this premalignant lesion is variable, with little evidence of its performance in Colombian patients.

Aims

The aim of this study is to determine the performance of LBC in the detection of premalignant lesions, in patients with ASC in CPS.

Materials and Methods

Were obtained patients who attended colposcopy clinic due the result of ASC in CPS. An LBC was taken, which was interpreted by two pathologists without access to other results. The performance of LBC to detect HSIL, was determined, considering as a gold standard: histopathological study/negative-satisfactory colposcopy.

Results

Were included 114 patients, with a mean age of 38.4 years (SD ± 13.3). LBC had abnormal results in 40.36% (n = 46), with a slightly higher proportion of low-grade squamous intraepithelial lesion (LSIL) than HSIL. The total of abnormal diagnoses by colposcopy and/or biopsy was 51.75% (n = 59), with a predominance of LSIL (36.84%). The sensitivity of the liquid-based cytology to detect premalignant lesions was 76.5%, specificity: 66.0%, positive predictive value: 28.3% and negative predictive value: 94.1%; The Cohen's kappa index of LBC for detecting HSIL was 0.2492 for the total population and 0.2907 for ≥30 years.

Discussion

Although LBC decreases abnormal cytology and increases the detection of HSIL, which improves diagnostic accuracy; sensitivity and predictive values for detecting HSIL are not significantly different between CPS and LBC.

Effective reduction in inadequate Pap smears by using a saline-lubricated speculum and two glass slides

OBJECTIVE

The aim of the study was to propose a method using saline lubrication and two glass slides to reduce the proportion of inadequate Pap smears.

MATERIALS AND METHODS

This was a retrospective study of patients at a medical center in eastern Taiwan that performs 5000-6000 Pap smears annually. The extracted data only detailed the number and percentage of inadequate Pap smears. We applied two modifications to the conventional Pap smear technique. The first modification was lubricating the speculum with normal saline instead of jelly. The second modification was performing the smear on two glass slides instead of just one. We used the modified technique beginning in January 2017. Therefore, we collected data from 2016 (before the modified technique was employed) and 2018 (after the modified technique was employed). The categorical data are presented as numbers (percentages). The differences in the number and percentage of inadequate smears resulting from both techniques were assessed using the Chi-square test.

RESULTS

During 2016 and 2018, 28 and 2 women received inadequate Pap smears among the total of 594 and 613 women who received Pap smears, respectively. The proportion of inadequate Pap smears was 4.71% and 0.33% in 2016 and 2018, respectively (P < 0.001).

CONCLUSIONS

The use of this modified technique effectively reduced the percentage of inadequate Pap smears.

High-risk human papillomavirus test in anal smears: can it optimize the screening for anal cancer?

OBJECTIVE

The current method for screening anal cancer is anal cytology, which has low sensitivity. Since high-risk human papillomavirus (HR-HPV) is associated with almost 90% of cases of anal cancer, the objective of this study is to evaluate whether testing for HR-HPV can optimize the screening.

DESIGN

Prospective study with patients enrolled in a screening program for anal dysplasia. Considering high-resolution anoscopy (HRA)-guided biopsy as the gold standard for diagnosis of high-grade squamous intraepithelial lesions, the diagnostic performance of anal cytology, HR-HPV testing, and the combination of both was calculated.

SETTINGS

A single center for anal dysplasia.

PARTICIPANTS

A total of 364 patients (72% males, 82% HIV-positive).

INTERVENTION

Patients underwent anal cytology, HR-HPV test, and HRA-guided biopsy of the anal canal.

MAIN OUTCOME MEASURES

Ability of cytology and HR-HPV test (individually and combined) to detect high-grade squamous intraepithelial lesions, and analysis of the cost of each diagnostic algorithm.

RESULTS

Cytology alone was the cheapest approach, but had the lowest sensitivity [59%, 95% confidence interval (CI) 46-71%], despite of highest specificity (73%, 95% CI 68-78%). Cotesting had the highest sensitivity (85%, 95% CI 74-93%) and lowest specificity (43%, 95% CI 38-49%), and did not seem to be cost-effective. However, HR-HPV testing can be used to triage patients with normal and atypical squamous cells of undetermined significance cytology for HRA, resulting in an algorithm with high sensitivity (80%, 95% CI 68-89%), and specificity (71%, 95% CI 65-76%), allied to a good cost-effectiveness.

CONCLUSION

HR-HPV testing is helpful to optimize the screening in cases of normal and atypical squamous cells of undetermined significance cytology.

Automatic model for cervical cancer screening based on convolutional neural network: a retrospective, multicohort, multicenter study

Background

The incidence rates of cervical cancer in developing countries have been steeply increasing while the medical resources for prevention, detection, and treatment are still quite limited. Computer-based deep learning methods can achieve high-accuracy fast cancer screening. Such methods can lead to early diagnosis, effective treatment, and hopefully successful prevention of cervical cancer. In this work, we seek to construct a robust deep convolutional neural network (DCNN) model that can assist pathologists in screening cervical cancer.

Methods

ThinPrep cytologic test (TCT) images diagnosed by pathologists from many collaborating hospitals in different regions were collected. The images were divided into a training dataset (13,775 images), validation dataset (2301 images), and test dataset (408,030 images from 290 scanned copies) for training and effect evaluation of a faster region convolutional neural network (Faster R-CNN) system.

Results

The sensitivity and specificity of the proposed cervical cancer screening system was 99.4 and 34.8%, respectively, with an area under the curve (AUC) of 0.67. The model could also distinguish between negative and positive cells. The sensitivity values of the atypical squamous cells of undetermined significance (ASCUS), the low-grade squamous intraepithelial lesion (LSIL), and the high-grade squamous intraepithelial lesions (HSIL) were 89.3, 71.5, and 73.9%, respectively. This system could quickly classify the images and generate a test report in about 3 minutes. Hence, the system can reduce the burden on the pathologists and saves them valuable time to analyze more complex cases.

Conclusions

In our study, a CNN-based TCT cervical-cancer screening model was established through a retrospective study of multicenter TCT images. This model shows improved speed and accuracy for cervical cancer screening, and helps overcome the shortage of medical resources required for cervical cancer screening.

Method for preservation of DNA stability of liquid-based cytology specimens from a lung adenocarcinoma cell line

Liquid-based cytology (LBC) specimens of lung adenocarcinoma have the potential to be widely used for genetic analysis. However, formaldehyde contained in some LBC preservation solutions can cause DNA fragmentation during specimen storage, rendering the samples unsuitable for molecular analysis. To investigate a novel preservation technique for improved DNA stability, which was evaluated by mutation analysis of epidermal growth factor receptor (EGFR) gene in human lung adenocarcinoma cell lines. Cells were fixed in CytoRich Red preservation solution. After 30 min of fixation, cells were either stored using the conventional method (suspended in preservation solution) or washed in phosphate-buffered saline and stored as a cell pellet (newly proposed method). The effect of storage was evaluated after 5, 7, and 9 days of storage at ambient temperature. The cell pellet group was also tested after 14 and 28 days. Specifically, we evaluated the DNA stability, DNA yield, and sample suitability for polymerase chain reaction (PCR), and EGFR mutation detection. The DNA yields and degree of stability from the cell pellet group were higher than those from the suspension group at every time point examined. PCR amplification from the cell pellet group was successful up to day 28. Mutation detection using the Cycleave PCR method indicated that the Ct values of the cell pellet group were significantly lower than those of the suspension group. Storing LBC specimens as a cell pellet post-fixation can maintain the DNA quality for a longer period than the conventional method, making it a promising strategy for molecular analysis.

Comparison between Conventional Cytology and Liquid-Based Cytology in the Tertiary Brazilian Navy Hospital in Rio de Janeiro

INTRODUCTION

Cervical cancer screening is an important tool in public health. Liquid-based cytology (LBC) has been performed at the studied hospital for 7 years. The present study compares the performance of 2 LBC techniques with conventional cytology.

OBJECTIVE

Our objective is to verify the sensitivity for the detection of neoplastic and preneoplastic epithelial atypia, as well as the positive predictive value of the 3 methodologies.

METHODS

We analyzed retrospectively 24,529 cases and evaluated the conventional cytology, ThinPrep®, and BD SurePath® performance categorizing the results according to the Bethesda system. We also compared the level of unsatisfactory samples, the presence of elements from the squamocolumnar junction, and the detection of pathogenic microorganisms.

RESULTS

ThinPrep® (1.43%) showed superior sensitivity over BD SurePath® (0.91%) and conventional cytology (0.71%) in terms of the detection of high-grade lesions; however, in terms of squamous atypia as a whole (ASC-US+), BD SurePath® (6.44%) proved to be more sensitive than conventional cytology (5.28%) and ThinPrep® (3.73%).

CONCLUSIONS

The results show the advantage of implementing LBC in routine screening for cervical lesions. In this study, BD SurePath® achieved the overall best performance considering the studied variables.

Comparison of liquid-based cytology with conventional smear cytology for EUS-guided FNA of solid pancreatic masses: a prospective randomized noninferiority study

BACKGROUND AND AIMS

There are limited data on the efficacy of liquid-based cytology (LBC) for EUS-guided FNA specimens. We aimed to evaluate the diagnostic efficacy of LBC for solid pancreatic neoplasms compared with conventional smears (CSs).

METHODS

In this randomized, crossover, noninferiority trial, we randomly assigned (1:1) patients with suspected pancreatic cancer to the LBC group or the CS group. Aspirates from the first needle pass were processed by one method, aspirates from the second pass by the other method, and specimens from the last pass were processed as core biopsy samples. The primary endpoint was the diagnostic efficacy of each method, with the final diagnosis as the gold standard. A noninferiority margin of -10% was assumed.

RESULTS

Of 170 randomized patients, 165 were classified as malignant and 5 as benign. Unsatisfactory samples were less frequent in the LBC group (1.78%) compared with the CS group (5.33%). The diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of LBC versus CS were 88.0% versus 83.8% (P = .276), 87.7% versus 83.2% (P = .256), 100% versus 100% (P = .999), 100% versus 100% (P = .999), and 16.7% versus 16.1% (P = .953), respectively. A bloody background was significantly more frequent in the CS group (CS, 85.2%; LBC, 1.8%; P < .001), whereas the nuclear features were similar for both groups.

CONCLUSIONS

The diagnostic usefulness of LBC was comparable with that of CS. The cytomorphologic features did not differ significantly between the 2 methods, and the reduced bloody backgrounds allowed better visibility in the LBC method. (Clinical trial registration number: NCT03606148.).

Effects of an Additional Liquid Based Cytology Prepate on Cytological Diagnosis in High-Risk HPV Positive, PaP Test Negative Cases

OBJECTIVES

To investigate the effects of a second cytology preparation on cytological diagnosis in high-risk HPV positive and PaP smear-negative cases.

METHODS

This retrospective study was conducted with 57 cases who underwent cytological evaluation and cotest in our center in 2016-2017. All of these cases were high-risk HPV positive, PaP smear-negative and had a second preparation. All preparations were re-evaluated by a cytopathologist and a pathologist. Twenty-five of the cases who had a positive diagnosis in the second preparation had a cervical biopsy.

RESULTS

In 46 (80%) of the cases, the cytological diagnosis was the same and negative in the first and second preparations. Second preparations of 11 cases (19.2%) were positive. Twenty of 25 patients (77%) with cervical biopsy had premalignant lesion.

CONCLUSION

In high-risk HPV positive and PaP smear-negative cases, patient management is different from cases where these two tests are positive together. According to our results, 19.2% of high-risk HPV positive and PaP smear-negative cases were given positive cytological diagnosis by second cytology preparation. Biopsy results support our cytological findings. The incidence of positive cytological diagnosis increases in PaP smear with the second preparation. With this protocol, patient management changes, follow-up time and number can be reduced.

Current Status of and Perspectives on Cervical Cancer Screening in Korea

Since the introduction of the Papanicolaou (Pap) smear system in 1943, cervicovaginal cytology has been used as a standard screening test for cervical cancer. The dissemination of this test contributed to reductions of the incidence and mortality of cervical cancer worldwide. In Korea, regular health check-ups for industrial workers and their family members were introduced in 1988 and were performed as part of the National Cancer Screening Program in 1999. As a result, the incidence of cervical cancer in Korea has been steadily decreasing. However, about 800 cases of cervical cancer-related deaths are reported each year due to false-negative test results. Hence, new screening methods have been proposed. Liquid-based cytology (LBC) was introduced in 1996 to overcome the limitations of conventional Pap smears. Since then, other LBC methods have been developed and utilized, including the human papilloma virus test-a method with higher sensitivity that requires fewer screenings. In this study, we review current issues and future perspectives related to cervical cancer screening in Korea.

Characterizing the Effect of Automated Cell Sorting Solutions on Cytomorphological Changes

INTRODUCTION

Liquid-based cytology has become a widely adopted, automated screening system for gynecologic and nongynecologic cytology. Automated screening systems function by distinguishing atypical cells based on their cytoplasmic and nuclear areas, densitometric measurement, and so on. However, the morphological influence of the washing solution has not been fully considered. Here, we examined the morphological effect and temporal change resulting from saving the cytologic samples in various solutions.

METHODS

Cytologic specimens were obtained from the ascites (AS) of patients with peritoneal cancer. Various solutions of a physiological saline, a Ringer's solution, a low-molecular dextran L injection, VOLUVEN 6% solution, MIXID L injection (ML), RPMI-1640 medium, and horse serum (HS) were added to aliquot sediments. All samples were refrigerated at 4°C, and aliquots were subsequently processed at specific time points (0, 1, 2, 4, 7, and 14 days). For all samples, cytoplasmic and nuclear size of the Papanicolaou-stained specimens were measured.

RESULTS

In terms of cytoplasmic and nuclear areas, samples stored in ML and HS showed no significant difference compared to the AS sample; in contrast, the other samples were significantly larger in both cytoplasmic and nuclear areas than the AS sample. In examining the temporal change among the solutions, we found that the cytoplasms and nuclei became small over the time course for all of the tested solutions.

CONCLUSION

We showed that cells swell in the solution after 1 h of storage and contract as time progresses. Together, our findings have important implications for how mathematical analysis is applied during the automated screening process.

Current Status of and Perspectives on Cervical Cancer Screening in Korea

Since the introduction of the Papanicolaou (Pap) smear system in 1943, cervicovaginal cytology has been used as a standard screening test for cervical cancer. The dissemination of this test contributed to reductions of the incidence and mortality of cervical cancer worldwide. In Korea, regular health check-ups for industrial workers and their family members were introduced in 1988 and were performed as part of the National Cancer Screening Program in 1999. As a result, the incidence of cervical cancer in Korea has been steadily decreasing. However, about 800 cases of cervical cancer-related deaths are reported each year due to false-negative test results. Hence, new screening methods have been proposed. Liquid-based cytology (LBC) was introduced in 1996 to overcome the limitations of conventional Pap smears. Since then, other LBC methods have been developed and utilized, including the human papilloma virus test-a method with higher sensitivity that requires fewer screenings. In this study, we review current issues and future perspectives related to cervical cancer screening in Korea.

Cervical Cancer Screening Programs in Europe: The Transition Towards HPV Vaccination and Population-Based HPV Testing

Cervical cancer is the fourth most frequently occurring cancer in women around the world and can affect them during their reproductive years. Since the development of the Papanicolaou (Pap) test, screening has been essential in identifying cervical cancer at a treatable stage. With the identification of the human papillomavirus (HPV) as the causative agent of essentially all cervical cancer cases, HPV molecular screening tests and HPV vaccines for primary prevention against the virus have been developed. Accordingly, comparative studies were designed to assess the performance of cervical cancer screening methods in order to devise the best screening strategy possible. This review critically assesses the current cervical cancer screening methods as well as the implementation of HPV vaccination in Europe. The most recent European Guidelines and recommendations for organized population-based programs with HPV testing as the primary screening method are also presented. Lastly, the current landscape of cervical cancer screening programs is assessed for both European Union member states and some associated countries, in regard to the transition towards population-based screening programs with primary HPV testing.

Reducing DNA damage by formaldehyde in liquid-based cytology preservation solutions to enable the molecular testing of lung cancer specimens

BACKGROUND

Liquid-based cytology (LBC) is a useful cytopathological method, and LBC lung adenocarcinoma specimens may be used for genetic analysis in the near future. In the current study, the authors determined whether LBC specimens can be used for epidermal growth factor receptor (EGFR) mutation analysis in human lung adenocarcinoma cell lines.

METHODS

Genomic DNA was extracted from 3 lung adenocarcinoma cell lines that were fixed in LBC preservation solution using 2 protocols (one for cultured cells and one for tissues) of a DNA extraction kit. Different fixation times were tested for each protocol: 30 minutes, 1 hour, and 1 to 9 days. As controls, cells also were fixed in 10% formalin or 95% ethanol. The authors investigated the effect of fixation time on DNA fragmentation, polymerase chain reaction (PCR) amplification, and EGFR mutation detection.

RESULTS

The DNA yield of LBC specimens tended to decrease depending on fixation time. When using the DNA extraction protocol for tissues, PCR amplification was successful after 9 days of fixation, although extracted genomic DNA that was fixed for >1 hour demonstrated fragmentation. Mutation analyses using the Cycleave PCR method were successful after 7 days of fixation. The DNA extraction protocol for tissues was appropriate for lung adenocarcinoma cell lines that were stored for >1 day in a preservative solution. The results of the current study demonstrated that EGFR mutations can be detected on day 7 using lung adenocarcinoma cell lines fixed in CytoRich Red preservative.

CONCLUSIONS

When LBC specimens are used for targeted molecular genetic testing, the appropriate preservative solution and extraction protocol first should be determined.

Cervical Cancer Detection between Conventional and Liquid Based Cervical Cytology: a 6-Year Experience in Northern Bangkok Thailand

Objectives:

To determine the prevalence of abnormal Papanicolaou (Pap) smear, cervical intraepithelial neoplasia (CIN) 2 or higher and cancer between conventional Pap smear (CPP) and liquid based Pap smear (LBP).

Methods:

This retrospective study was conducted at Bhumibol Adulyadej Hospital, Bangkok, Thailand between January 2011 and December 2016. Data was collected from medical records of participants who attended for cervical cancer screening test. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy for detecting CIN 2 or higher were evaluated by using the most severity of histopathology reports.

Results:

A total of 28,564 cases were recruited. Prevalence of abnormal Pap smear from CPP and LBP were 4.8 % (1,092/22,552) and 5.7 % (345/6,012), respectively. Percentage of unsatisfactory smears in CPP (52.3%) was higher than LBP (40.5%). From CPP and LBP, cervical cancer percentages were 0.2 and 0.1, respectively. Sensitivity, specificity, PPV, NPV and accuracy of CPP and LBP for detection cancer were 42.5 vs 26.1%, 99.9 vs 100.0%, 69.8vs 75.0%, 99.7 vs 100.0 % and 99.7 vs 99.7%, respectively.

Conclusion:

Prevalence of abnormal cervical cytology and cancer from CPP and LBP were 4.8/0.2 and 5.7/0.1 percent, respectively. Unsatisfactory smear of LBP was less than CPP. Sensitivity, specificity, PPV, NPV and accuracy of CPP and LBP for detection CIN 2 or higher and cancer were comparable.