Evolution of Pap testing at a community hospital: a ten year experience

Molecular markers for cervical cancer screening

INTRODUCTION

Cervical cancer remains a significant healthcare problem, notably in low- to middle-income countries. While a negative test for hrHPV has a predictive value of more than 99.5%, its positive predictive value is less than 10% for CIN2+ stages. This makes the use of a so-called triage test indispensable for population-based screening to avoid referring women, that are ultimately at low risk of developing cervical cancer, to a gynecologist. This review will give an overview of tests that are based on epigenetic marker panels and protein markers.

AREAS COVERED

There is a medical need for molecular markers with a better predictive value to discriminate hrHPV-positive women that are at risk of developing cervical cancer from those that are not. Areas covered are epigenetic and protein markers as well as health economic considerations in view of the fact that most cases of cervical cancer arise in low-to-middle-income countries.

EXPERT OPINION

While there are biomarker assays based on changes at the nucleic acid (DNA methylation patterns, miRNAs) and at the protein level, they are not widely used in population screening. Combining nucleic acid-based and protein-based tests could improve the overall specificity for discriminating CIN2+ lesions that carry a low risk of progressing to cervical cancer within the screening interval from those that carry an elevated risk. The challenge is to reduce unnecessary referrals without an undesired increase in false-negative diagnoses resulting in cases of cervical cancer that could have been prevented. A further challenge is to develop tests for low-and middle-income countries, which is critical to reduce the worldwide burden of cervical cancer.

Nationwide survey of cervical cytology laboratory practices in China

INTRODUCTION

Cervical cancer rates in China remain high, with only limited opportunistic screening in urban centers and large mostly unscreened rural areas. Cervical cytology practices in China have been changing over the last decade with introduction of The Bethesda System reporting terminology, liquid-based cytology (LBC), and programs for cervical cytology screening of underserved rural populations. An effort was undertaken for the first time to collect nationwide data on cervical cytology laboratory practices in China, a possible first step toward increased standardization and potential development of nationwide cytology quality benchmarks.

MATERIALS AND METHODS

Data on cervical cytology practices from 1572 laboratories operating in 26 nationwide Provisional Level Administrative Divisions was collected in an online survey approved through the Obstetrics and Gynecology Hospital of Fudan University in Shanghai.

RESULTS

Over 90% of cervical cytology laboratories in China now solely use Bethesda System reporting terminology. LBC is now the most commonly utilized form of cervical cytology, with lower-cost Chinese-manufactured LBC formulations used in almost 70% of laboratories. Nationwide, significantly higher abnormal cytology rates were reported with LBC than with the conventional Papanicolaou smear (CPS); however, the CPS remains a useful low-cost alternative as China strives to extend cervical screening to large underserved rural areas.

CONCLUSIONS

Abnormal cytology rates were not significantly different when different levels of hospitals were compared. The survey identified nationwide opportunities for cytology quality improvement, including low rates of reporting of unsatisfactory cases and low rates for atypical glandular cells.

Enhanced Detection of Cervical Cancer and Precancer Through Use of Imaged Liquid-Based Cytology in Routine Cytology and HPV Cotesting

OBJECTIVES

Cervical screening strives to prevent cervical cancer (CxCa), minimizing morbidity and mortality. Most large US reports on cytology and human papillomavirus (HPV) cotesting of women aged 30 years and older are from one laboratory, which used conventional Papanicolaou (Pap) smears from 2003 to 2009.

METHODS

We quantified detection of CxCa and precancer (cervical intraepithelial neoplasia 3/adenocarcinoma in situ [CIN3/AIS]) in 300,800 cotests at Magee Womens Hospital since 2005. Screening histories preceding CxCa and CIN3/AIS diagnoses were examined to assess the contribution of cytology and HPV testing. Cotesting utilized Food and Drug Administration-approved imaged liquid-based cytology (LBC) and from-the-vial HPV tests.

RESULTS

LBC identified more women subsequently diagnosed with CxCa and CIN3/AIS than HPV testing. HPV-negative/cytology-positive results preceded 13.1% of CxCa and 7.2% of CIN3/AIS diagnoses.

CONCLUSIONS

LBC enhanced cotesting detection of CxCa and CIN3/AIS to a greater extent than previously reported with conventional Pap smear and HPV cotesting.

Cytological Characteristics of Endometrial Phasing Using the Specimens Prepared with the Liquid-Based Procedure: Comparison with the Conventional Procedure

OBJECTIVE

To evaluate whether or not the liquid-based procedure (LBP) for endometrial cytology is as worthwhile for endometrial phasing as conventional slides.

MATERIALS AND METHODS

The subjects were 81 women who underwent endometrial cytology and were defined as negative. The specimens obtained by either Endocyte® or Masubuchi aspiration tube® were processed first with the conventional procedure and then with LBP using TACAS™.

RESULTS

(1) The number of subjects diagnosed by the conventional method as having proliferative, mid-, middle-secretory and late-secretory and atrophic phases was 40, 11, 10, 0 and 20, respectively. The rate of agreement with those using LBP was 87.7%. (2) Incidences of large clusters, ductal clusters, palisade arrangement, uneven staining and dirty mucous background detected were significantly higher with the conventional method, whereas with LBP clean background, inconspicuous bonding of cells, scattered solitary glandular cells, clear well-stained cytoplasm and cell compactness were higher. (3) Especially in the proliferative phase, clusters tended to be smaller and lose their architectural structures, and scattered solitary columnar cells were present. (4) Cells in the mid-phase tended to have loose contact and to mimic other phases.

CONCLUSIONS

Cytodiagnosis of endometrial phasing prepared with LBP is feasible to perform when some modifications are implemented.

Automatic Detection of Cervical Cancer Cells by a Two-Level Cascade Classification System

We proposed a method for automatic detection of cervical cancer cells in images captured from thin liquid based cytology slides. We selected 20,000 cells in images derived from 120 different thin liquid based cytology slides, which include 5000 epithelial cells (normal 2500, abnormal 2500), lymphoid cells, neutrophils, and junk cells. We first proposed 28 features, including 20 morphologic features and 8 texture features, based on the characteristics of each cell type. We then used a two-level cascade integration system of two classifiers to classify the cervical cells into normal and abnormal epithelial cells. The results showed that the recognition rates for abnormal cervical epithelial cells were 92.7% and 93.2%, respectively, when C4.5 classifier or LR (LR: logical regression) classifier was used individually; while the recognition rate was significantly higher (95.642%) when our two-level cascade integrated classifier system was used. The false negative rate and false positive rate (both 1.44%) of the proposed automatic two-level cascade classification system are also much lower than those of traditional Pap smear review.

Cervical Cytology Reporting Rates from China's Largest College of American Pathologists-Certified Laboratory with a Focus on Squamous Cell Carcinoma Cytology and Its Histopathological Follow-Up Results

OBJECTIVE

No organized cervical screening programs or national cervical cytology quality control standards currently exist in China. This study reported cervical cytology performance in China's largest independent laboratory with accreditation from the College of American Pathologists.

DESIGN

Results from over 2 million Papanicolaou (Pap) tests by the KingMed Diagnostics Laboratory were categorized according to The Bethesda System (TBS) from 2007 and 2014. Pap reports and histopathologic follow-up results of squamous cell carcinomas (SCC) were analyzed.

RESULTS

Data on 676,445 conventional Pap smears (CPS) and 1,696,284 liquid-based cytology (LBC) specimens were available. Abnormality rates reported were significantly higher with LBC than with CPS in all TBS categories (p < 0.001). A total of 800 SCC cytology reports were identified, representing a laboratory SCC reporting rate of 0.0337%. The SCC reporting rate with LBC (0.0457%) was significantly higher than the reporting rate with CPS. Histopathologic invasive cervical carcinoma and cervical intraepithelial neoplasia 2/3 were diagnosed in 80.7 and 17.6% of the 119 patients with SCC Pap cytology.

CONCLUSIONS

Reporting rates for most TBS categories from this CAP-accredited laboratory in China were within the CAP benchmark ranges except for low atypical glandular cell and unsatisfactory case rates. Histological follow-up results in patients with SCC cytology reports demonstrate very high specificity of SCC Pap cytology.

Evaluation of a New Automated Processing System (TACAS™ Pro) for Liquid-Based Procedures

OBJECTIVE

To evaluate a fully automated processing system (TACAS™ Pro) for liquid-based procedures (LBPs).

METHODS AND MATERIALS

Materials were 3,483 and additionally 502 specimens that were taken at Kanagawa Health Service Association. Specimens obtained with a Cervex-Brush® were first smeared to glass slides using one side of the brush and then processed to TACAS Pro.

RESULTS

(1) The microscopy watching time per normal case was 3.65 ± 0.85 min in the conventional procedure, whereas in the LBP it was 1.95 ± 0.60 min, and the latter reduced workload to 53%. (2) The handling time of TACAS Pro per day was 2 h and 25.8 min. The workload at a laboratory offset it and revealed the work saving to be 63.8%. (3) Unsatisfactory rates were 0% in the conventional procedure, whereas in the LBP it was 1.88% at first. The latter rate decreased to 0.5% after system improvement. (4) Specimens which may disturb microscopy analysis were found in 1.06%, including 3 cases of possible carry-over of cells to the following slides. An additional study with the revised system confirmed no carry-over. (5) Incidences of abnormal cytology were consistent between the two methods.

CONCLUSIONS

The revised automated processing system TACAS Pro is a feasible and useful LBP and reduces the workload of cytology laboratories.

Bethesda System reporting rates for conventional Papanicolaou tests and liquid-based cytology in a large Chinese, College of American Pathologists-certified independent medical laboratory: analysis of 1394389 Papanicolaou test reports

CONTEXT

Reports that use the Bethesda System categories for Chinese Papanicolaou test results are rare.

OBJECTIVE

To document and analyze rates reported in the Bethesda System for conventional Papanicolaou tests and liquid-based cytology between 2007 and 2012 in China's largest College of American Pathologists-accredited laboratory.

DESIGN

Results from 1,394,389 Papanicolaou tests, rendered between 2007 and 2012 by the Guangzhou Kingmed Diagnostics Cytology Laboratory, were documented by the Bethesda System report categories and Papanicolaou test methodology, which included both conventional Papanicolaou tests and 4 different liquid-based cytology preparations.

RESULTS

Results were documented for 326,297 conventional Papanicolaou tests and 1,068,092 liquid-based cytology specimens, which included 928,884 ThinPrep (Hologic, Bedford, Massachusetts), 63,465 SurePath (BD Diagnostics, Franklin Lakes, New Jersey), 50,422 Liqui-Prep (LGM International, Melbourne, Florida), and 25,321 Lituo liquid-cytology (Lituo Biotechnology Co, Hunan, China) specimens. Abnormality rates reported were significantly higher with liquid-based cytology than they were with conventional Papanicolaou tests in all the Bethesda System categories (P < .001). Reporting rates were within the 2006 benchmark ranges from the College of American Pathologists, except for atypical glandular cells (low) and unsatisfactory rates for conventional Papanicolaou tests (low).

CONCLUSION

Participation in the international College of American Pathologists Laboratory Accreditation Program provides laboratory quality standards not otherwise available in many international settings.

PPV of an HSIL cervical cytology result in China's largest CAP-certified laboratory

INTRODUCTION

Cervical cancer remains a major health problem in China, where no uniform national standards for cervical cytology quality control exist. This study extends previously reported findings on cervical cytology performance in China's largest independent laboratory to have achieved accreditation under the international Laboratory Accreditation Program of the College of American Pathologists.

MATERIALS AND METHODS

A retrospective study identified high-grade squamous intraepithelial lesion (HSIL) cervical cytology reports between 2007 and 2013 from the Cytology Laboratory, Guangzhou Kingmed Diagnostics. Four liquid-based cytology (LBC) preparations were used in 73% of cases and conventional Papanicolaou tests (CPT) in 27%. Follow-up histopathologic diagnoses after HSIL reports were identified in the laboratory database. The positive predictive value for laboratory HSIL cytology results was determined for follow-up histopathologic diagnoses of cervical intraepithelial neoplasia 2 or worse (CIN2+), a recognized international quality control monitor.

RESULTS

Of 1,804,108 cervical cytology reports, 11,929 HSIL reports (0.66%) were identified. The LBC HSIL rate was 0.79%, which was higher than the CPT HSIL rate of 0.33% (P < 0.001). Follow-up CIN2+ histopathologic diagnoses within 6 months after HSIL were identified in 1994 of 2414 patients (82.6%), including 1860 of 2246 LBC HSIL (82.8%) and 134 of 168 CPT HSIL (79.8%). Cervical cancers were diagnosed on follow-up in 244 of 2414 HSIL cases (10.1%).

CONCLUSIONS

The positive predictive value of HSIL cervical cytology results for follow-up histopathologic CIN2+ was within currently recognized benchmark ranges for cytology laboratories. The high rate of cervical cancer diagnoses likely reflects the largely unscreened population. The College of American Pathologists Laboratory Accreditation Program provided quality standards not otherwise available in many international settings.

Comparison of 2 anal cytology protocols to predict high-grade anal intraepithelial neoplasia

OBJECTIVES

Nylon-flocked and Dacron swab anal cytology collection procedures were evaluated for detecting high-grade anal intraepithelial neoplasia.

MATERIALS AND METHODS

Cross-sectional data for 42 HIV-infected and 16 uninfected men who have sex with men have been used. Sequentially collected anal cytology specimens, high-resolution anoscopy, and medical biopsy evaluated the sensitivity and specificity of cytology for predicting high-grade anal intraepithelial neoplasia. Men showing atypical squamous cells (ASC) or more severe findings by cytology were compared with those showing negative for intraepithelial lesions.

RESULTS

The prevalence of high-grade anal intraepithelial neoplasia was 35% (21/58), and findings were approximately 1.5 times higher among HIV-infected compared with uninfected men. Unsatisfactory cytology was twice as common among Dacron compared with nylon-flocked swab protocol specimens (14% [8/58] vs 7% [4/58]). Sensitivity and specificity for the nylon-flocked protocol cytology showing ASC or more severe findings were 81% (58%-95%) and 73% (50%-89%), respectively. Dacron protocol specimens showed 52% (30%-74%) and 58% (34%-80%) sensitivity and specificity, respectively. Men showing ASC or more severe findings using the nylon-flocked protocol cytology showed 3-fold higher odds for high-grade anal intraepithelial neoplasia compared with men with negative results (p < .05), but no statistically significantly higher odds of high-grade anal intraepithelial neoplasia for men showing ASC or more severe findings compared with those with negative results for Dacron protocol cytology (p > .05).

CONCLUSIONS

The nylon-flocked protocol better detects high-grade anal intraepithelial neoplasia than does the Dacron protocol, yields more interpretable results, and classifies men with high-grade anal intraepithelial neoplasia as cytologically abnormal 2.5 times more often, even in this small clinical trial.

CLINICAL TRIALS REGISTRATION NUMBER

NCT00955591.

Screening test results associated with cancer diagnoses in 287 women with cervical squamous cell carcinoma

CONTEXT

The limitations of newer cervical screening tests are still being studied.

OBJECTIVE

To investigate those limitations, we conducted a retrospective review of 287 cases of cervical squamous cell carcinoma (SCC).

DESIGN

A search through 5 years of records identified 287 women with cervical SCC diagnoses. Clinical history, histopathology, and liquid-based cytology (ThinPrep) and Hybrid Capture 2 (HC2) high-risk human papillomavirus (HPV) results were documented. Polymerase chain reaction HPV tests were performed on SCC tissues with prior negative HC2 results.

RESULTS

Of 287 women, 156 (54.4%) had abnormal cytology results, and 75 (26.1%) had abnormal clinical findings triggering tissue diagnoses of SCC. Among 156 patients with abnormal Papanicolaou (Pap) test results, more-seriously abnormal Pap test results were reported in 142 women (91.1%). Among 31 women with Pap and HC2 HPV cotesting within 1 year of SCC diagnoses, 28 (90%) were Pap⁺/HPV⁺, 2 (15.5%) were Pap⁺/HPV⁻, and 1 (3%) was Pap⁻/HPV⁻. Two of 3 women with negative HC2 results before SCC diagnosis had abnormal Pap results; 1 had negative Pap reports with questionable lesional cells mimicking atrophy. In all 3 cases of SCC with negative HC2 results, HPV-18 was detected; in 2 cases (66%), HPV-16 was also detected.

CONCLUSIONS

Although abnormal cytology preceded most SCC diagnoses, about one-third of patients were referred for diagnostic testing because of clinical suspicion alone. Among 31 SCC cases with liquid-based cytology and high-risk HPV cotest results less than 1 year before SCC diagnoses, 2 patients (6.5%) had Pap⁺/HPV⁻ results, and 1 patient (3.2%) had Pap⁻/HPV⁻ results. Polymerase chain reaction detected high-risk HPV DNA in tumor tissues of 3 SCC cases with recent HC2⁻ results.

Unsatisfactory rates vary between cervical cytology samples prepared using ThinPrep and SurePath platforms: a review and meta-analysis

OBJECTIVE

To compare unsatisfactory rates between the two major liquid-based cytology (LBC) platforms, namely ThinPrep (Hologic) and SurePath (Becton Dickinson).

DESIGN

The authors performed both a systematic review and a meta-analysis. Inclusion criteria were English language, data presented on unsatisfactory rates for either ThinPrep or SurePath, utilising actual patient samples (ie, not laboratory manipulated samples) and no manipulation using acetic acid to increase the satisfactory rate. The authors searched PubMed for articles using the keywords 'SurePath' or 'ThinPrep' and 'unsatisfactory'. References of retrieved studies were searched for additional articles. Key researchers in the field were also contacted.

PARTICIPANTS AND INTERVENTIONS

Eligible studies were reviewed for rates of unsatisfactory cervical cytology smears processed on either the ThinPrep or SurePath platforms (compared with a general linear model) or data on unsatisfactory rates for both platforms for the same laboratory and the same patient population (compared with a meta-analysis using a random effects model and pooled RR).

PRIMARY OUTCOME MEASURE

Unsatisfactory rate of cervical cytology smears.

RESULTS

A total of 1 120 418 cervical cytology smears were reported in 14 different studies using the SurePath platform for an overall unsatisfactory rate (weighted average) of 0.3%. 28 studies reported on 1 148 755 smears prepared using the ThinPrep platform for an overall unsatisfactory rate (weighted average) of 1.3%. The general linear model did not show a difference between LBC platforms when other variables were controlled for; however, the power to detect a difference (0.087) was very low. The meta-analysis performed on four studies where both ThinPrep and SurePath results were reported from the same laboratory showed fewer unsatisfactory tests from the SurePath platform (RR 0.44, 95% CI 0.25 to 0.77, p=0.004).

CONCLUSIONS

Multiple factors affect LBC unsatisfactory rates. In a meta-analysis, cervical cytology samples prepared on the SurePath platform show significantly fewer unsatisfactory smears than those prepared on the ThinPrep platform.

Unsatisfactory SurePath liquid-based Papanicolaou tests: causes and significance

BACKGROUND

The introduction of liquid-based Papanicolaou (Pap) tests (LBPTs) has reduced the incidence of unsatisfactory Pap tests (UPTs), but little is known about their causes and significance, especially in the case of SurePath LBPTs.

METHODS

All unsatisfactory LBPTs from January 1, 2003 to December 31, 2006 were retrieved. The characteristics of patients, providers, and LBPTs; the reason for UPTs; and any cytologic or histologic follow-up within 24 months were recorded. Negative Pap tests that were evaluated immediately after a UPT served as a control group.

RESULTS

Of 243,006 Pap tests (95.5% SurePath LBPTs), 0.23% were unsatisfactory. Scant cellularity was the primary cause of SurePath UPT. Women in this UPT group were older, had more diagnostic Pap tests taken, less frequently were taking contraceptives or were pregnant, and were more likely to be menopausal or posthysterectomy. The 278 women who had UPTs had significantly higher rates of follow-up Pap tests (65.1% vs 22.2%), abnormal Pap tests (5.4% vs 1.4%), biopsies (10% vs 1%), and abnormal biopsies (5% vs 1%) than the 284 women in the control group, including 7 women with cervical intraepithelial neoplasia 1 (CIN-1), 1 woman with CIN-2, 4 women with CIN-3, and 2 women with endometrial hyperplasia. The UPT rates varied little between provider groups (physicians vs nonphysicians and gynecologists vs nongynecologists).

CONCLUSIONS

The frequency of UPTs in a predominantly SurePath LBPT-screened population was very low and was caused mainly by low cellularity. Similar to conventional Pap smears, unsatisfactory SurePath LBPTs had a higher risk of significant histologic abnormalities on follow-up than negative satisfactory Pap tests and could have benefited from a repeat Pap test or other evaluation, according to current management guidelines.

Superior performance of liquid-based versus conventional cytology in a population-based cervical cancer screening program

OBJECTIVE

Liquid-based cytology may offer improvements over conventional cytology for cervical cancer screening. The two cytology techniques were compared in a group of 86,469 women who participated in a population-based screening program. Using a nation-wide pathology database containing both cervical cytology and histology records for all patients, we compared the outcome of the two screenings methods with regard to the detection rate of histological proven abnormalities and the determination of the true false-negative rates for both methods.

METHODS

Two cohorts of women living in the same geographical region were used. Cohort 1 (n=51,154 women) was analysed using conventional cytology (conventional cohort) and cohort 2 (liquid cohort) (n=35,315 women) was analysed using liquid-based cytology (SurePath). The samples were processed in one laboratory. The results of histological follow up were available via a central database.

RESULTS

The rate of unsatisfactory slides was significantly lower using liquid-based cytology (0.13% vs. 0.89%, p<0.0001). Detection of ASCUS+ (Atypical squamous cells of unknown significance or higher abnormalities) was significantly higher using liquid-based cytology (2.97% vs. 1.64%, p<0.0001), mainly due to the increase in the ASCUS category. The percentage of histological abnormalities within the ASCUS samples was approximately equal in both cohorts, indicating that more true abnormal cases were detected using liquid-based cytology. The sensitivity for detection of a histological proven lesion is significantly higher in the liquid cohort compared to the conventional cohort (96.2% vs. 92.0%), with only a slight difference in specificity (97.8% vs. 98.2%).

CONCLUSION

This population study confirmed previous institution-based reports of decreased numbers of unsatisfactory samples based on liquid-based cytology and showed an increased sensitivity for the detection of cytological abnormalities that was validated by subsequent histological investigation.

Cervical cancer screening: from molecular basis to diagnostic practice, going through new technologies

In the era of Human Papillomavirus (HPV) vaccination, a lot of misunderstanding still exists among healthcare professionals and patients regarding HPV infection. The purpose of this review is to synthesize the clinical molecular mechanisms that contribute to HPV-mediated cervical carcinogenesis, as well as to appraise the current status of new biomarkers and technologies in terms of available data on clinical applications and future promises.