Cytologic detection of cervical abnormalities using liquid-based compared with conventional cytology: a randomized controlled trial

The reporting rates of high-grade squamous intraepithelial lesions and their human papillomavirus testing and histologic follow-up results: A comparison between ThinPrep and SurePath preparations

BACKGROUND

Liquid-based cytology (LBC) tests SurePath (SP) and ThinPrep (TP) have largely replaced conventional Papanicolaou (Pap) tests for cervical cytology screening due to higher sensitivity. However, comparison between SP and TP test sensitivity and efficacy in detecting squamous abnormalities is lacking. Our study aims to compare high-grade squamous intraepithelial lesion (HSIL) reporting rates, human papillomavirus (HPV) positivity rates, and histologic outcome between these two LBC methods.

MATERIALS AND METHODS

We performed a retrospective search of the period between January 2014 and June 2017, when both TP and SP were utilized at our institution, to identify HSIL cases and collect the HPV testing and histologic follow-up results for those cases.

RESULTS

One hundred twenty-five HSILs were identified from the 15 382 TP specimens (0.81%) and 93 HSILs were identified from the 25 105 SP specimens (0.37%), a statistically significant difference (P < .0001). The corresponding HPV positivity rates were 95.6% and 89.7% in TP-HSILs and SP-HSILs, respectively, a statistically non-significant difference. Histologic follow-up showed HSILs or carcinomas were identified in 78% (49/63) of TP-HSILs and 79% (45/57) of SP-HSILs, with no statistically significant difference.

CONCLUSION

TP demonstrated a higher HSIL detection rate than SP with no significant difference in follow-up HPV or histologic results.

Increased Risk of High-grade Cervical Neoplasia in Women with Inflammatory Bowel Disease: A Case-controlled Cohort Study

BACKGROUND AND AIMS

Women with inflammatory bowel disease [IBD] may be at higher risk for cervical intraepithelial neoplasia [CIN]. However, data are conflicting. The aim of this study was to assess the risk of high-grade dysplasia and cancer [CIN2+] in IBD women and identify risk factors.

METHODS

Clinical data from adult IBD women in a multicentre Dutch IBD prospective cohort [PSI] from 2007 onwards were linked to cervical cytology and histology records from the Dutch nationwide cytology and pathology database [PALGA], from 2000 to 2016. Patients were frequency-matched 1:4 to a general population cohort. Standardised detection rates [SDR] were calculated for CIN2+. Longitudinal data were assessed to calculate CIN2+ risk during follow-up using incidence rate ratios [IRR] and risk factors were identified in multivariable analysis.

RESULTS

Cervical records were available from 2098 IBD women [77%] and 8379 in the matched cohort; median follow-up was 13 years. CIN2+ detection rate was higher in the IBD cohort than in the matched cohort (SDR 1.27, 95% confidence interval [CI] 1.05-1.52). Women with IBD had an increased risk of CIN2+ [IRR 1.66, 95% CI 1.21-2.25] and persistent or recurrent CIN during follow-up (odds ratio [OR] 1.89, 95% CI 1.06-3.38). Risk factors for CIN2+ in IBD women were smoking and disease location (ileocolonic [L3] or upper gastrointestinal [GI] [L4]). CIN2+ risk was not associated with exposure to immunosuppressants.

CONCLUSIONS

Women with IBD are at increased risk for CIN2+ lesions. These results underline the importance of human papillomavirus [HPV] vaccination and adherence to cervical cancer screening guidelines in IBD women, regardless of exposure to immunosuppressants.

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.

A comparison of liquid-based and conventional cytology using data for cervical cancer screening from the Japan Cancer Society

OBJECTIVE

Liquid-based cytology has replaced conventional cytology in cervical cancer screening in many countries. However, a detailed comparison of liquid-based cytology with conventional cytology has not been reported in Japan. Therefore, the aim of the study is to evaluate efficacy of liquid-based cytology in Japan.

METHODS

We first evaluated the prevalence of use of liquid-based cytology and then examined the efficacy of liquid-based cytology and conventional cytology for detecting CIN and the rate of unsatisfactory specimens using data from cancer screening collected by the Japanese Cancer Society from FY2011 to FY2014. A Poisson regression model with random effects analyses was used to classify histological outcomes and unsatisfactory specimens using liquid-based cytology compared to conventional cytology.

RESULTS

A total of 3 815 131 women were analyzed in the study. The rate of liquid-based cytology increased from approximately 8% in FY2011 to 37% in FY2014. Compared to conventional cytology, the detection rates with liquid-based cytology were significantly higher (1.42 times) for CIN1+ [detection rate ratio (DRR) = 1.42, 95% confidence interval (CI) 1.35-1.48, P < 0.001] and CIN2+ (DRR = 1.16, 95% CI 1.08-1.25, P < 0.001). Positive predictive value ratios of CIN1+ and CIN2+ were also significantly higher for liquid-based cytology than for conventional cytology. However, there was no significant difference between liquid-based cytology and conventional cytology for detection rates and positive predictive values of CIN3+ and cancer. The rate of unsatisfactory specimens was significantly lower with liquid-based cytology compared to conventional cytology (DRR = 0.07, 95% CI 0.05-0.09, P < 0.001).

CONCLUSIONS

In order to avoid the unsatisfactory specimens in cervical cancer screening, the results of this study did indicate that liquid-based cytology was more useful than conventional cytology in practical standpoints.

Can LBC Completely Replace Conventional Pap Smear in Developing Countries

Background

A number of screening techniques have been developed to reduce the incidence of cervical cancer, most common of which is conventional Pap smear (CPS) being overtaken by liquid-based cytology (LBC) in most of the developed countries. There are a number of studies with conflicting results, and no method has been shown superior in terms of all parameters. LBC was introduced in our hospital in 2014, and we planned to do a study and compare results of the two techniques. This study aims to compare the two methods in terms of sensitivity, specificity, positive predictive value and negative predictive value, turnover time, cost-effectiveness, sample adequacy. This study has been done in 100 women with unhealthy cervix to increase the output.

Method

This was a prospective observational study. A total of 100 women fulfilling the inclusion criteria were subjected to screening test. In first 50 cases, first conventional Pap smear was taken and then LBC, and in remaining 50 cases, first LBC and then conventional Pap smear were taken; this was done to remove bias.

Results

The number of unsatisfactory slides was reduced with LBC, and turnover time was less for LBC. The detection of ASCUS was increased with LBC, but the detection of higher-grade lesions (HSIL and SCC) was equal with both tests.

Conclusion

The superiority of LBC with respect to reduction in the number of unsatisfactory slides and less turnover time is being offset with increased detection of low-grade lesions subjecting women to further testing increasing the cost of programme and anxiety among women. It is difficult to say that it can completely replace conventional Pap smear in low-resource settings.

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 incidence after normal cytological sample in routine screening using SurePath, ThinPrep, and conventional cytology: population based study

Objective To compare the cumulative incidence of cervical cancer diagnosed within 72 months after a normal screening sample between conventional cytology and liquid based cytology tests SurePath and ThinPrep.Design Retrospective population based cohort study.Setting Nationwide network and registry of histo- and cytopathology in the Netherlands (PALGA), January 2000 to March 2013.Population Women with 5 924 474 normal screening samples (23 833 123 person years).Exposure Use of SurePath or ThinPrep versus conventional cytology as screening test.Main outcome measure 72 month cumulative incidence of invasive cervical cancer after a normal screening sample for each screening test. Cox regression analyses assessed the hazard ratios, adjusted for calendar time, age, screening history, and socioeconomic status and including laboratories as random effects.Results The 72 month cumulative cancer incidence was 58.5 (95% confidence interval 54.6 to 62.7) per 100 000 normal conventional cytology samples, compared with 66.8 (56.7 to 78.7) for ThinPrep and 44.6 (37.8 to 52.6) for SurePath. Compared with conventional cytology, the hazard of invasive cancer was 19% lower (hazard ratio 0.81, 95% confidence interval 0.66 to 0.99) for SurePath, mainly caused by a 27% lower hazard (0.73, 0.57 to 0.93) of a clinically detected cancer. For ThinPrep, the hazard was on average 15% higher (hazard ratio 1.15, 0.95 to 1.38), mainly caused by a 56% higher hazard of a screen detected cancer (1.56, 1.17 to 2.08).Conclusions These findings should provoke reconsideration of the assumed similarity in sensitivity to detect progressive cervical intraepithelial neoplasia between different types of liquid based cytology and conventional cytology.

A comparison of liquid-based cytology with conventional Papanicolaou smears in cervical dysplasia diagnosis

Background:

Due to the high number of women affected by cervical cancer and the importance of an early diagnosis, combined with the frequent incidence of false-negative Papanicolaou (Pap) smear screening results for this disease, several studies have been conducted in recent years in order to find better tests. Liquid-based cytology (LBC) tests, including the liquid-based thin layer method, have demonstrated the highest potential for reducing false-negative cases and improved sample quality. This study aimed to compare the strength of the Pap smear test with fluid cytology and conventional tests in detecting cervical dysplasia.

Materials and Methods:

This descriptive-analytic study was conducted on 366 women who attended private laboratories for a Pap smear. The Pap smear sampling was conducted simultaneously using two methods: conventional Pap (CP) smear and LBC), from the cervix.

Results:

The mean age of the participants was 32 ± 8.8 years. Diagnostic results of endocervical cells, epithelial cells, vaginitis cells, and metaplastia were consistent with both conventional and liquid cytology smears, and the kappa coefficient was determined to be significant (P < 0.001). In total, 40.5% of diagnostic cases indicated bacterial inflammation 80.3% of the diagnoses in both methods were P1 and 3.9% of cases diagnosed were P2, the overall diagnostic consistency was 83.9% between the two sampling methods. The inflammation diagnosis was 40.5% and this was consistent in both methods of LBC and CP. There was one case of a false-negative diagnosis in the LBC method and 14 cases in the CP method.

Conclusion:

Results showed that the LBC may improve the sample's quality and reduce the number of unsatisfactory cases more than with the CP method.

Comparison of Efficacy in Abnormal Cervical Cell Detection between Liquid-based Cytology and Conventional Cytology

This study was conducted to 1206 women who had cervical cancer screening at Chonburi Cancer Hospital. The spilt-sample study aimed to compare the efficacy of abnormal cervical cells detection between liquid-based cytology (LBC) and conventional cytology (CC). The collection of cervical cells was performed by broom and directly smeared on a glass slide for CC then the rest of specimen was prepared for LBC. All slides were evaluated and classified by The Bethesda System. The results of the two cytological tests were compared to the gold standard. The LBC smear significantly decreased inflammatory cell and thick smear on slides. These two techniques were not difference in detection rate of abnormal cytology and had high cytological diagnostic agreement of 95.7%. The histologic diagnosis of cervical tissue was used as the gold standard in 103 cases. Sensitivity, specificity, positive predictive value, negative predictive value, false positive, false negative and accuracy of LBC at ASC-US cut off were 81.4, 75.0, 70.0, 84.9, 25.0, 18.6 and 77.7%, respectively. CC had higher false positive and false negative than LBC. LBC had shown higher sensitivity, specificity, PPV, NPV and accuracy than CC but no statistical significance. In conclusion, LBC method can improve specimen quality, more sensitive, specific and accurate at ASC-US cut off and as effective as CC in detecting cervical epithelial cell abnormalities.

Comparing SurePath, ThinPrep, and conventional cytology as primary test method: SurePath is associated with increased CIN II+ detection rates

Purpose

Within the last decade, SurePath and ThinPrep [both liquid-based cytology (LBC) tests] have replaced conventional cytology (CC) as primary test method in cervical cancer screening programs of multiple countries. The aim of our study was to examine the effect in the Dutch screening program.

Methods

All primary smears taken within this program from 2000 to 2011 were analyzed using the nationwide registry of histo- and cytopathology (PALGA) with a follow-up until March 2013. The percentage of smears classified as borderline/mildly dyskaryotic (BMD) and >BMD as well as CIN and cervical cancer detection rates were compared between SurePath and ThinPrep versus CC by logistic regression analyses (adjusted for age, screen region, socioeconomic status, and calendar time).

Results

We included 3,118,685 CC, 1,313,731 SurePath, and 1,584,587 ThinPrep smears. Using SurePath resulted in an increased rate of primary smears classified as >BMD [odds ratio (OR) = 1.12 (95% confidence interval (CI) 1.09–1.16)]. CIN I and II⁺ detection rates increased by 14 % [OR = 1.14 (95% CI 1.08–1.20)] and 8 % [OR = 1.08 (95% CI 1.05–1.12)]. Cervical cancer detection rates were unaffected. Implementing ThinPrep did not result in major alterations of the cytological classification of smears, and it did not affect CIN detection rates. While not significant, cervical cancer detection rates were lower [OR = 0.87 (95% CI 0.75–1.01)].

Conclusions

The impact of replacing CC by LBC as primary test method depends on the type of LBC test used. Only the use of SurePath was associated with increased CIN II⁺ detection, although it simultaneously increased the detection of CIN I.

Five-Year Cervical (Pre)Cancer Risk of Women Screened by HPV and Cytology Testing

Primary human papillomavirus (HPV)-based cervical screening will be introduced in the Netherlands in 2016. We assessed the 5-year cervical (pre)cancer risk of women with different combinations of HPV and cytology test results. Special attention was paid to risks for cervical intraepithelial neoplasia grade 3 and 2 or more (CIN3+/2+) of HPV-positive women with a negative triage test, because this determines the safety of a 5-year screening interval for HPV-positive, triage test-negative women. In addition, age-related effects were studied. A total of 25,553 women were screened by HPV testing and cytology in a screening setting. Women were managed on the presence of HPV and/or abnormal cytology. Five-year cumulative incidences for CIN3+/2+ were calculated. Five-year CIN3+(2+) risk was 10.0% (17.7%) among HPV-positive women. When stratified by cytology, the CIN3+(CIN2+) risk was 7.9% (12.9%) for women with normal cytology and 22.2% (45.3%) for women with equivocal or mildly abnormal (i.e., BMD) cytology. For HPV-negative women, the 5-year CIN3+(2+) risk was 0.09% (0.21%). Additional triage of HPV-positive women with normal cytology by repeat cytology at 12 months showed a 5-year CIN3+(2+) risk of 4.1% (7.0%). HPV-non 16/18-positive women with normal cytology at baseline had comparable risks of 3.5% (7.9%). HPV-non 16/18-positive women with normal baseline cytology and normal repeat cytology had a 5-year CIN3+ risk of 0.42%. No age-related effects were detected. In conclusion, HPV-positive women with normal cytology and a negative triage test, either repeat cytology after 12 months or baseline HPV 16/18 genotyping, develop a non-negligible CIN3+ risk over 5 years. Therefore, extension of the screening interval over 5 years only seems possible for HPV screen-negative women.

Impact of technology on cytology outcome in cervical cancer screening of young and older women

Little is known about age-dependent variation in outcomes of cervical cytology with modern technologies. This population-based study evaluated age-dependent changes after routine implementation of ThinPrep and SurePath technology in two independent laboratories, and controlled for time trends in a third laboratory using manually read conventional cytology continually. Data were collected from the Danish National Health Care Registers. For each laboratory, we compared proportions of abnormal cytology defined as atypical squamous cells of undetermined significance or worse (ASCUS+) by age and technology phase. The study included 489,960 cytological samples with no recent abnormality from women aged 23-59 years, routinely screened between 1998 and 2007. Implementation of SurePath liquid-based cytology (LBC) was followed by an increase in abnormal cytology in women aged 23-29 years from 4.6 to 6.1%, relative proportion (RP): 1.31 [95% confidence interval (CI): 1.08-1.61], and a decrease in women aged 45-59 years from 2.9 to 2.0%, RP: 0.71 (95% CI: 0.60-0.83). Implementation of ThinPrep LBC was followed by a decrease in abnormal cytology both in women aged 23-29 years from 7.7 to 6.8%, RP: 0.89 (95% CI: 0.78-1.02) and in women aged 45-59 years from 3.4 to 1.0%, RP: 0.30 (95% CI: 0.24-0.37). With implementation of imaging-assisted reading, regardless of the brand of technology, the proportion of abnormality increased by around 30% in all age groups (range from 19 to 41%). In the laboratory with unchanged technology no trends in abnormality proportions were observed. The impact of LBC implementation on cytological abnormality proportions varied considerably across age groups.

A randomized trial comparing conventional cytology to liquid-based cytology and computer assistance

Liquid-based cytology (LBC) has replaced conventional cytology (CC) for cervical cancer screening in some countries. However, it remains unclear whether LBC is superior to CC. A randomized controlled trial was conducted between August 2007 and March 2009 in Germany to compare LBC, alone and in combination with computer-assisted imaging technology (CAS), to CC in the detection of histologically confirmed cervical intraepithelial neoplasia (CIN). The main outcome measures were detection rates, relative sensitivities, positive predictive values (PPVs) and relative PPVs comparing LBC without and with CAS to CC. Primary histological outcome was CIN2 or higher. Included were 20,627 women participating in opportunistic cervical cancer screening at 20 gynecologic practices. The practices were randomized weekly to use LBC (n = 11,331) or CC (n = 9,296). Patients with positive findings were invited to expert colposcopy. The relative sensitivity of LBC versus CC using the CIN2+ cut-off was 2.74 (95% confidence interval [CI] 1.66-4.53). The relative sensitivity of LBC/CAS versus CC for CIN2+ was 3.17 (95% CI 1.94-5.19). The PPV of LBC and CC for CIN2+ was 48% and 38%, respectively. The PPV ratio did not differ significantly from unity. Differences between LBC and CC were smaller in some sensitivity and subgroup analyses; however, relative sensitivity of LBC remained increased. LBC without and with CAS compared with CC under the field conditions of an opportunistic screening system had a significantly higher sensitivity for the detection of CIN without deterioration of PPVs. Additional use of CAS did not further improve sensitivity of LBC. © 2012 Wiley Periodicals, Inc.

Liquid-based cervical cytology using ThinPrep technology: weighing the pros and cons in a cost-effectiveness analysis

PURPOSE

Cervical cancer screening with liquid-based cytology (LBC) has been developed as an alternative to the conventional Papanicolaou (CP) smear. Cost-effectiveness is one of the issues when evaluating LBC. Based on the results of a Dutch randomised controlled trial, we conducted cost-effectiveness threshold analyses to investigate under what circumstances manually screened ThinPrep LBC is cost-effective for screening.

METHODS

The MISCAN-Cervix microsimulation model and data from the Dutch NETHCON trial (including 89,784 women) were used to estimate the costs and (quality-adjusted) life years ((QA)LYs) gained for EU screening schedules, varying cost-effectiveness threshold values. Screening strategies were primary cytological screening with LBC or CP, and triage with human papillomavirus (HPV) testing.

RESULTS

Threshold analyses showed that screening with LBC as a primary test can be cost-effective if LBC is less than <euro>3.2 more costly per test than CP, if the sensitivity of LBC is at least 3-5 % points higher than CP, if the quality of life for women in triage follow-up is only 0.39, or if the rate of inadequate CP smears is at least 16.2 %.

CONCLUSIONS

Regarding test characteristics and costs of LBC and CP, only under certain conditions will a change from CP to manually screened ThinPrep LBC be cost-effective. If none of these conditions are met, implementation of manually screened ThinPrep LBC seems warranted only if there are advantages other than cost-effectiveness. Further research is needed to establish whether other LBC systems will be more favorable with regard to cost-effectiveness.

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.

Causes and Relevance of Unsatisfactory and Satisfactory but Limited Smears of Liquid-Based Compared With Conventional Cervical Cytology

Context.—Recent randomized controlled trials have shown a significant decrease in unsatisfactory rates for liquid-based cytology (LBC) compared with conventional Papanicolaou test (CP). The underlying causes and relevance of unsatisfactory results for LBC and CP have never been compared within the setting of a randomized controlled trial.

Objective.—To examine differences in causes and relevance of unsatisfactory and satisfactory but limited by (SBLB) results for LBC and CP.

Design.—Data from the Netherlands ThinPrep Versus Conventional Cytology (NETHCON) trial were used, involving 89 784 women. Causes and relevance of unsatisfactory and SBLB results were analyzed.

Results.—The primary cause for unsatisfactory results for CP and LBC was scant cellularity. Other causes for unsatisfactory CPs were virtually eliminated with LBC. The same was true for SBLB subcategories, with the exception of SBLB absence of transformation zone component and SBLB scant cellularity. The SBLB absence of transformation zone component showed a statistically significant 22% and SBLB scant cellularity a 12% nonsignificant increase with LBC. The detection rates of abnormalities found during 18 months of follow-up of unsatisfactory test results did not differ significantly between the 2 study arms, nor did they differ from the initial test positivity rates from the NETHCON trial.

Conclusions.—Liquid-based cytology shows an almost complete elimination of most causes for unsatisfactory CP, with scant cellularity remaining as the sole cause for unsatisfactory LBC. On the other hand, with LBC a significant increase of smears without a transformation zone component was noted. Women with an unsatisfactory test result are not at increased risk for cervical abnormalities either with LBC or with CP.

Trial Registration.—Nederlands Trial Register, NTR1032, www.trialregister.nl.

Patients with cervical cancer: why did screening not prevent these cases?

OBJECTIVE

The objective of the study was to assess the screening history of women with cervical cancer and review normal cervical smears 5 years preceding the diagnosis.

STUDY DESIGN

Cytological and histological results of 401 women treated for invasive cervical cancer between 1991 and 2008 at the Radboud University Nijmegen Medical Center were studied. Ninety-eight normal smears were reviewed.

RESULTS

Of the 401 women, 269 (67%) received at least 1 invitation for the national screening program for cervical cancer (NCSP). One- third fell outside the target age of the NCSP. Seventeen percent never responded to the invitation(s). Twenty-one percent had 1 or more normal smears within 5 years preceding the diagnosis. After review, only 39% of those smears were reviewed as a normal smear.

CONCLUSION

Half of the women with cervical cancer were never screened because of the limited target age range or nonattendance. Twenty-one percent had a normal smear within 5 years preceding the diagnosis, caused by interpretation and/or sampling errors.

Age-specific patterns of unsatisfactory results for conventional Pap smears and liquid-based cytology: data from two randomised clinical trials

OBJECTIVE

To investigate the rate of unsatisfactory cervical cell samples in liquid-based cytology (LBC) versus conventional cytology (CC) by age.

DESIGN

Randomised clinical trials.

SETTING

Population-based cervical cancer screening in the Netherlands and Italy.

POPULATION

Asymptomatic women invited for screening enrolled in two randomised trials: Netherlands ThinPrep versus conventional cytology (NETHCON; 39 010 CC, 46 064 LBC) and New Technologies in Cervical Cancer Screening (NTCC; 22 771 CC, 22 403 LBC).

METHODS

Comparison of categorical variables using Pearson's chi-square test, logistic regression and trend tests.

MAIN OUTCOME MEASURES

Proportion of unsatisfactory samples, ratio of LBC versus CC, and variation by 5-year group.

RESULTS

In NETHCON, a lower percentage of LBC samples were judged to be unsatisfactory compared with CC samples (0.33 versus 1.11%). There was no significant trend in unsatisfactory results by age group for conventional cytology (P(trend) = 0.54), but there was a trend towards an increasing percentage of unsatisfactory results with increasing age for LBC (P(trend) < 0.001). In NTCC, a lower percentage of LBC samples were judged to be unsatisfactory compared with conventional cytology (2.59 versus 4.10%). There was a decrease in the unsatisfactory results by age group with conventional cytology (P(trend) < 0.001) and with LBC (P(trend) = 0.01), although the latter trend arose from the 55-60-years age group (P(trend) = 0.62 when excluding this group).

CONCLUSIONS

The clinical trial in which the results were collected and the cytologic method used were the most important determinants of unsatisfactory cytology. In all situations, the proportion of unsatisfactory samples was lower in LBC compared with CC. The effects of age depended on the criteria used to define unsatisfactory results.

How to evaluate emerging technologies in cervical cancer screening?

Excellent recommendations exist for studying therapeutic and diagnostic questions. We observe that good guidelines on assessment of evidence for screening questions are currently lacking. Guidelines for diagnostic research (STARD), involving systematic application of the reference test (gold standard) to all subjects of large study populations, are not pertinent in situations of screening for disease that is currently not yet present. A five-step framework is proposed for assessing the potential use of a biomarker as a screening tool for cervical cancer: i) correlation studies establishing a trend between the rate of biomarker expression and severity of neoplasia; ii) diagnostic studies in a clinical setting where all women are submitted to verification by the reference standard; iii) biobank-based studies with assessment in archived cytology samples of the biomarker in cervical cancer cases and controls; iv) prospective cohort studies with baseline assessment of the biomarker and monitoring of disease; v) randomised intervention trials aiming to observe reduced incidence of cancer (or its surrogate, severe dysplasia) in the experimental arm at subsequent screening rounds. The 5-phases framework should guide researchers and test developers in planning assessment of new biomarkers and protect clinicians and stakeholders against premature claims for insufficiently evaluated products.

Use of flow cytometry as a quality control device for liquid-based cervical cytology specimens

BACKGROUND

Cervical cancer is the second most common cancer in women worldwide comprising a major concern of public health. Liquid-based cytology provides significantly more effective detection of low-grade intraepithelial neoplasia or more severe lesions, without loss of diagnostic specificity and reduces the number of cases classified as unsatisfactory. The objective of the study is the evaluation of flow cytometry as a rapid tool for quality control of the liquid specimen adequacy for the purpose of precise cytological diagnosis in detecting cervical abnormalities.

METHODS

A total of 1,854 women undergoing routine cervical cytology joined this cohort study. A monolayer smear was prepared and 1 ml aliquot was removed and prepared for flow cytometric analysis. Cells were fixed and run on a Partec CyFlow SL, with front scatter (FSS) and side scatter (SSC) set on logarithmic scale. The forward scatter versus side scatter dot-plot was used for the distinction of ectocervical, endocervical, and polymorphonuclear cells.

RESULTS

In the total of 1,854 cases, 15 specimens (0.8%) were characterized by the cytopathologist as unsatisfactory. Inadequacy was confirmed by flow cytometric analysis for four samples. Monolayer smears were reprepared for the remaining 11 samples. After the second microscopic observation, six out of the 11 cases (54.5%) were found to be satisfactory, whereas the remaining five were still designated as unsatisfactory by the cytopathologist.

CONCLUSION

The parallel screening of adequacy by quantification of cell populations with flow cytometry can serve as an internal control for diagnosis and can overall decrease the number of unsatisfactory samples.