Diagnostic value of urine erythrocyte morphology in the detection of glomerular disease in SurePath™ liquid‐based cytology compared with fresh urine sediment examination

H. Ohsaki, T. Hirouchi, N. Hayashi, E. Okanoue, M. Ohara, N. Kuroda, E. Hirakawa and Y. Norimatsu
Diagnostic value of urine erythrocyte morphology in the detection of glomerular disease in SurePath? liquid‐based cytology compared with fresh urine sediment examination Objective: To assess whether the morphology of urine erythrocytes can be an effective tool for distinguishing glomerular disease from lower urinary tract disease in SurePath^? liquid‐based cytology (SP‐LBC). Methods: We examined four morphological parameters of erythrocytes: (1) irregular erythrocytes (of all types including fragmented forms) comprising greater than or equal to 20% of erythrocytes; (2) uniform erythrocytes (>80%); (3) doughnut or target‐like shaped (D/T) erythrocytes (≥1%); and (4) acanthocytes (≥1%) in glomerular disease (n = 32) and lower urinary tract disease (n = 20) with SP‐LBC slides in cases that had also been assessed by fresh urine sediment examination. Results: Sensitivity of D/T erythrocytes and acanthocytes (dysmorphic erythrocytes) for glomerular disease were 100% and 87.5%, respectively, with urine sediment examination, and 81.3% and 46.9%, respectively, in SP‐LBC slides. Specificity was 100% for D/T erythrocytes and acanthocytes using either procedure. While irregular erythrocytes were specific for glomerular disease using urine sediment examination, they were seen in 70% of those with lower urinary tract disease using SP‐LBC slides as a result of the deformation of erythrocytes by the fixative. Conclusions: Although the sensitivity of D/T erythrocytes and acanthocytes for glomerular disease was lower in SP‐LBC slides than fresh urine sediment examination, their specificity was equally high. Therefore, urine erythrocyte morphology is useful in the detection of glomerular disease with the SP‐LBC slides. However, morphological features apart from D/T erythrocytes and acanthocytes are not useful in SP‐LBC slides.     

Prospective parallel randomized trial of the MultiCyte™ ThinPrep® imaging system: the Scottish experience

T.J. Palmer, S.M. Nicoll, M.E. McKean, A.J. Park, D. Bishop, L. Baker and J.E.A. Imrie
Prospective parallel randomized trial of the MultiCyte? ThinPrep^® imaging system: the Scottish experience Background: Computer‐assisted screening of cervical liquid‐based cytology (LBC) preparations using the ThinPrep® Imaging System (TIS) has shown improved qualitative and quantitative gains. The use of Multicyte? has not been described in a well‐established national screening programme with a low incidence of high‐grade dyskaryosis. Objectives: To assess the impact of computer‐assisted screening within the Scottish Cervical Screening Programme (SCSP). Methods: Two groups of three laboratories, each sharing a ThinPrep® Imager, screened 79 366 slides randomized to test and 90 551 to control arms by laboratory accession. Screeners were not blinded. Standard laboratory reporting profiles of the SCSP, sensitivity, specificity and false‐negative rates of all grades of LBC abnormalities with respect to final cytology reports, predictive value for cervical intraepithelial neoplasia grade 2 or worse (CIN2+) on histology; and screening rates were compared for both arms. Results: Inadequate and negative reporting rates were significantly lower and low‐grade reporting rates significantly higher in the imager arm. Imager‐assisted screening showed significantly better specificity than manual screening with respect to the final cytology result. There was no evidence of a significant difference in the detection of CIN2 + or CIN3 + . Positive, abnormal and total predictive values (high‐grade, low‐grade and all abnormal cytology found to be CIN2 + , respectively) were similar in both arms. Productivity was significantly higher in the imager arm. Conclusion: Computer‐assisted screening in a well established screening programme showed significantly improved productivity without loss of quality. These findings should inform future policy for cervical screening programmes.     

Proposed Sheffield quantitative criteria in cervical cytology to assist the diagnosis and grading of squamous intra-epithelial lesions, as some Bethesda system definitions require amendment

Objective: This study assesses the accuracy of published quantitative and qualitative criteria in the Bethesda System (TBS) for squamous intra‐epithelial lesions. Methods: Quantitative image analysis was undertaken on illustrations from TBS publications and also from slides in Cytology Training Centre teaching sets. Comparisons were also made with the British Society for Clinical Cytology (BSCC) terminology in cervical cytology, using the illustrations in their terminology publication and amalgamating the results into their proposed new two‐tier model. Results: TBS quantitatively defines low‐grade squamous intra‐epithelial lesions (LSIL) in both conventional and liquid‐based cytology (LBC) preparations as showing nuclear enlargement more than ×3 the area of a normal intermediate squamous cell nucleus. This study found that the increase in mean nuclear area was limited to only ×2 in conventional preparations. In LBC (SurePath^TM) preparations, there was only a statistically non‐significant ×1.2 increase. This study identified a progressive and statistically significant reduction in mean cytoplasmic area from normal intermediate cells to LSIL and then to high‐grade squamous intra‐epithelial lesions (HSIL) in both conventional and LBC preparations. Furthermore, the most consistent quantitative finding in both conventional and LBC preparations was a statistically significant increase in the mean area and diameter ratios from normal intermediate cells to LSIL and then to HSIL. In all instances this varied from ×2 to just below ×3. This is in agreement with TBS, which states that the cytoplasmic area in HSIL is decreased leading to a marked increase in nuclear to cytoplasmic (NC) ratio. With the exception of an increase in mean nuclear area in conventional preparations from normal intermediate cells to LSIL, the predominant cause for this increase in NC ratios was a reduction in mean cytoplasmic area. The numerical increase in NC ratio for LSIL identified in this study was greater than implied by the ‘slightly increased’ statement in TBS. TBS comments that some HSIL cells can have the same degree of nuclear enlargement as in LSIL and that other HSIL cells may have much smaller nuclei than in LSIL. Both of these qualitative comments were supported in this study. The mean diameter NC ratios of 33% and 50% could provide useful diagnostic assistance in the distinction of normal intermediate cells and LSIL and between LSIL and HSIL, respectively. Because of overlapping individual ranges, however, additional diagnostic features such as nuclear morphology must be used in the distinction of normal intermediate cells, LSIL and HSIL. No statistical difference was identified in the mean diameter NC ratios between ASC‐US and LSIL in TBS publications. In addition, the proposed new BSCC low and high grades of squamous abnormality were not statistically different from ASC‐US/LSIL and HSIL, respectively. This provides support that the proposed BSCC two‐tier system of squamous abnormalities is comparable to TBS. This study shows that LBC has variable but major and significant effects on nuclear and cytoplasmic morphology and that quantitative definitions in conventional preparations cannot be automatically extrapolated to LBC methodology. Conclusions: The study shows that some TBS quantitative and qualitative criteria require amendment and that an alternative quantitative approach, such as diameter NC ratio has a more valid scientific evidence base. Furthermore, use of NC ratios avoids the problems associated with the variable changes in nuclear and cytoplasmic areas, occurring between conventional and different commercial LBC preparations. By contrast, classifications based on area comparisons must be tailored to the specific conventional or commercial LBC preparation.     

An audit of liquid‐based cervical cytology screening samples (ThinPrep and SurePath) reported as glandular neoplasia

S. A. Thiryayi, J. Marshall and D. N. Rana
An audit of liquid‐based cervical cytology screening samples (ThinPrep and SurePath) reported as glandular neoplasia Objectives: The aims of this study were to assess the number of cases diagnosed as glandular neoplasia (national report code 6) of cervical (6A) and non‐cervical (6B) types on ThinPrep (TP) and SurePath (SP) liquid‐based cytology (LBC) samples and to calculate the positive predictive value (PPV) of these diagnoses for significant glandular and/or squamous pathology for local audit and as a contribution to national data on glandular neoplasia. Methods: A computerized search identified all screening LBC samples reported as glandular neoplasia during the 24‐month period from January 2006 to December 2007. Corresponding histology samples were identified, with a minimum follow‐up period of 6 months for each case. Results: A total of 70 samples, representing 70 patients, were reported as glandular neoplasia, 39 TP (55.7%) and 31 SP (44.3%), with 46 samples (31 TP, 15 SP) reported as 6A and 24 samples (eight TP, 16 SP) as 6B. PPV of glandular neoplasia was calculated for a biopsy diagnosis of cervical glandular intraepithelial neoplasia/adenocarcinoma and/or cervical intraepithelial neoplasia (CIN) 2 or worse. The PPV of 6A was 100% for both TP and SP. The PPV of 6B for adenocarcinoma was 62.5% for TP and 66.7% for SP. The combined PPV for 6A + 6B was 92.3% for TP, 83.3% for SP and 88.4% combined. The overall pick‐up rates for the two methods were significantly different (TP 0.031%, SP 0.052%; P = 0.014). Histology showed only CIN3 with endocervical crypt involvement in nine TP cases and one SP case.     

O‐4CHARACTERISTICS OF FALSE NEGATIVE LBC SAMPLES

Background: Liquid based cytology (LBC) is the method of choice for the processing of samples in the cervical screening programme in England and Wales. Two LBC systems are in use; ThinPrep® and SurePath®. The manufacturers of SurePath® recommend that slides are screened in two separate directions perpendicular to each other (bidirectional screening) during the initial learning period. There is currently no evidence to evaluate whether this method is superior to screening in one direction only (unidirectional). Objectives: To compare the detection rate of high‐grade dyskaryosis in SurePath® preparations between screeners who used a unidirectional method and screeners who used a bidirectional method, to see if the screening method influenced detection rate. Methods: A questionnaire was sent to 23 screening staff at our Cytology Centre in October 2005, enquiring as to the method they used to screen SurePath® slides, as well as the grade of staff and the number of years experience they had screening cervical cytology slides. The staff were divided into two groups based on whether they screened unidirectionally or bidirectionally. A retrospective computerised search of all the slides screened by the staff for the period September 2004 to August 2005 was carried out, and the high‐grade detection rate at primary screening for the groups were calculated. Further analysis was carried out to determine the statistical significance of any difference between the two groups, as well as to account for potential confounding factors. Results: Initial results suggesting a statistically significant difference between the screening methods were later shown to be confounded by experience. Critical analysis of the data and study design reveal that no firm conclusions can be made on the basis of this work. Conclusion: No firm conclusions on screening method can be drawn due to fundamental limitations and confounding factors in this retrospective work‐based study. Recommendations for further studies are made, controlling for confounding factors.     

Semantic Focusing Allows Fully Automated Single-Layer Slide Scanning of Cervical Cytology Slides

Liquid-based cytology (LBC) in conjunction with Whole-Slide Imaging (WSI) enables the objective and sensitive and quantitative evaluation of biomarkers in cytology. However, the complex three-dimensional distribution of cells on LBC slides requires manual focusing, long scanning-times, and multi-layer scanning. Here, we present a solution that overcomes these limitations in two steps: first, we make sure that focus points are only set on cells. Secondly, we check the total slide focus quality. From a first analysis we detected that superficial dust can be separated from the cell layer (thin layer of cells on the glass slide) itself. Then we analyzed 2,295 individual focus points from 51 LBC slides stained for p16 and Ki67. Using the number of edges in a focus point image, specific color values and size-inclusion filters, focus points detecting cells could be distinguished from focus points on artifacts (accuracy 98.6%). Sharpness as total focus quality of a virtual LBC slide is computed from 5 sharpness features. We trained a multi-parameter SVM classifier on 1,600 images. On an independent validation set of 3,232 cell images we achieved an accuracy of 94.8% for classifying images as focused. Our results show that single-layer scanning of LBC slides is possible and how it can be achieved. We assembled focus point analysis and sharpness classification into a fully automatic, iterative workflow, free of user intervention, which performs repetitive slide scanning as necessary. On 400 LBC slides we achieved a scanning-time of 13.9±10.1 min with 29.1±15.5 focus points. In summary, the integration of semantic focus information into whole-slide imaging allows automatic high-quality imaging of LBC slides and subsequent biomarker analysis.     

Control specimens for immunocytochemistry in liquid‐based cytology

T. Hansen, H. Pedersen, V. Brauner and J. Hariri Control specimens for immunocytochemistry in liquid‐based cytology Objective Immunostaining necessitates the use of positive as well as negative controls, which is usually an easy procedure in immunohistochemistry (IHC). To find suitable control specimens for immunocytochemistry (ICC) is, on the other hand, a challenging task and to the best of our knowledge is not sufficiently dealt with in the English literature. The aim of this trial was to develop an applicable method to select, collect, process and store control specimens for ICC using liquid‐based cytology (LBC). Methods The study included 21 different antibodies, which were known to react with at least one of the cellular components from tonsils, serous fluids and bronchial washings. The LBC specimens from the tonsils were collected as SurePath? specimens (BD, Bencton, Dickinson and Company) by brushing the cut‐surface of a fresh tonsil and then immersing the brush head into the SurePath? vial. The serous fluids and bronchial washings were fixed in CytoRich Red? (BD). Some of the cellular suspensions from the tonsils and equal amounts of the serous fluid and the bronchial washings were also mixed as a cocktail. Unstained SurePath slides were then prepared on the PrepStain? (BD) Non‐GYN Program, and the unstained and dry slides were then stored at 5 °C to test the effect of storage on the preservation of the antigenicity. ICC was then performed on BenchMark‐XT?. Results Cellular components in unstained SurePath? slides reacted positively with relevant antibodies. Slides that were stored for up to 40 days did not loose staining intensity. Conclusion Specimens from body fluids and cell‐suspensions that are collected by brushing the cut‐surface from different types of fresh tissues or organs can be used as control specimens either separately or as mixtures. Dry and unstained slides can then be prepared and stored in a refrigerator for at least 40 days without loosing staining intensity.     

The BSCC Code of Practice – exfoliative cytopathology (excluding gynaecological cytopathology)

Exfoliative cytopathology (often referred to as non‐gynaecological cytology) is an important part of the workload of all diagnostic pathology departments. It clearly has a role in the diagnosis of neoplastic disease but its role in establishing non‐neoplastic diagnoses should also be recognised. Ancillary tests may be required to establish a definitive diagnosis. Clinical and scientific teamwork is essential to establish an effective cytology service and staffing levels should be sufficient to support preparation, prescreening, on‐site adequacy assessment and reporting of samples as appropriate. Routine clinical audit and histology/cytology correlation should be in place as quality control of a cytology service. Cytology staff should be involved in multidisciplinary meetings and appropriate professional networks. Laboratories should have an effective quality management system conforming to the requirements of a recognised accreditation scheme such as Clinical Pathology Accreditation (UK) Ltd. Consultant pathologists should sign out the majority of exfoliative cytology cases. Where specimens are reported by experienced biomedical scientists (BMS), referred to as cytotechnologists outside the UK, this must only be when adequate training has been given and be defined in agreed written local protocols. An educational basis for formalising the role of the BMS in exfoliative cytopathology is provided by the Diploma of Expert Practice in Non‐gynaecological Cytology offered by the Institute of Biomedical Science (IBMS). The reliability of cytological diagnoses is dependent on the quality of the specimen provided and the quality of the preparations produced. The laboratory should provide feedback and written guidance on specimen procurement. Specimen processing should be by appropriately trained, competent staff with appropriate quality control. Microscopic examination of preparations by BMS should be encouraged wherever possible. Specific guidance is provided on the clinical role, specimen procurement, preparation and suitable staining techniques for urine, sputum, semen, serous cavity effusion, cerebrospinal fluid, synovial fluid, cyst aspirates, endoscopic specimens, and skin and mucosal scrapes.     

Factors contributing to false‐negative and potential false‐negative cytology reports in SurePath™ liquid‐based cervical cytology

N. Gupta, D. John, N. Dudding, J. Crossley and J. H. F. Smith
Factors contributing to false‐negative and potential false‐negative cytology reports in SurePath ? liquid‐based cervical cytology Objectives: The characteristics of false‐negative conventional cervical cytology smears have been well documented, but there is limited literature available for liquid‐based cytology (LBC), especially SurePath? samples. We aimed to assess the characteristics of false‐negative SurePath LBC samples. Methods: Over a period of 5 years, an audit of false‐negative reports in SurePath cervical cytology was undertaken. In a workload of 183, 112 samples, 481 (0.3%) false negatives were identified using two routes: those detected by routine laboratory internal quality control (rapid pre‐screening) (n = 463) and those reported as normal (true false negatives) with concurrent high‐grade cervical histology (n = 18). Ninety‐five false‐negative cases with a subsequent biopsy reported as at least cervical intraepithelial neoplasia grade 2 (CIN2+) were reviewed for a number of different cytomorphological features. Results: Of 95 samples with subsequent CIN2+, 30.5% predominately contained microbiopsies/hyperchromatic crowded cell groups (HCGs), 27.3% sparse dyskarytotic cells, 4.2% pale cell dyskaryosis, 6.3% small dyskaryotic cells; 3.2% were misinterpreted cells, 8.4% contained other distracting cells, 7.4% were low contrast, 5.3% were unexplained and 7.4% were true negatives. The mean number of microbiopsies/HCGs in that category was 4.6. The mean number of abnormal cells in the sparse dyskaryotic cell category was 13.8. Conclusions: Microbiopsies/HCGs were the commonest reason for false negatives. They were usually present in sufficient numbers to be detected but interpretation could be problematic. Dispersed single abnormal cells were usually not identified because of their scarcity or the presence of distracters.     

Comparison of ThinPrep and conventional preparations on fine needle aspiration cytology material

OBJECTIVE: To compare the various cytologic features on ThinPrep 2000 (TP) (Cytyc Corporation, Marlborough, Massachusetts, U.S.A.) and conventional preparation (CP) specimens from fine needle aspiration cytology (FNAC) material by a semiquantitative scoring system. STUDY DESIGN: In this prospective study a total of 71 consecutive cases were included. In each case, two passes were performed. The first pass was used for conventional preparations, with direct smears made and fixed immediately in 95% alcohol for Papanicolaou stain. For TP preparation a second pass produced material for processing in the ThinPrep 2000. The TP and CP slides were studied independently by two observers and representative slides of CP and TP compared for cellularity, background blood and necrotic cell debris, cell architecture, informative background, presence of monolayer cells, and nuclear and cytoplasmic details by a semiquantitative scoring system. Statistical analysis was performed by Wilcoxon's signed rank test on an SPSS program (Chicago, Illinois, U.S.A.). RESULTS: TP preparations contained adequate diagnostic cells in all cases and were tangibly superior to CP preparations concerning monolayer cells, absence of blood and necrosis, and preservation of nuclear and cytoplasmic detail (statistically significant, Wilcoxon's signed rank test, P < .000). CONCLUSION: TP preparations are superior to conventional preparations with regard to clear background, monolayer cell preparation and cell preservation. It is easier and less time consuming to screen and interpret TP preparations because the cells are limited to smaller areas on clear backgrounds, with excellent cellular preservation. However, TP preparations are more expensive than CP and require some experience for interpretation.     

Significance of bizarre cells in cervical screening liquid‐based cytology: A prospective study of 15 cases

Objective

The aim of this study was to assess the significance of bizarre cells (cells of squamous origin with a superficial squamous cell‐type cytoplasm and characterised by multinucleation that produces bizarre nuclear shapes) in liquid‐based cytology (LBC) Papanicoaou (pap) smears with clinical and histological follow‐up correlation.

Methods

Fifteen patients, all with LBC samples containing bizarre cells, were identified in routine ThinPrep^® LBC workload. HPV testing was performed in each case using residual LBC material. Cytological‐histological correlations were reviewed.

Results

All 15 LBC samples contained bizarre cells and tested positive for high‐risk HPV types. Ten of the 15 cases were identified as atypical squamous cells ‐ cannot exclude an HSIL (ASC‐H) with secondary diagnosis of low‐grade squamous intraepithelial lesion (LSIL), while five cases were identified as high‐grade squamous intraepithelial lesion (HSIL), and a subsequent biopsy was recommended. Additionally, 13/15 cases underwent cone biopsy or hysterectomy within 1‐11 months, of which 10 showed histologically confirmed HSIL end‐points. LSIL was present in three cases. Bizarre cells were identified in the HSIL epithelium of five cone biopsies.

Conclusions

Identification of bizarre cells in LBC is straightforward and may facilitate diagnosis. The cytology of bizarre cells is associated with HSIL in cone biopsies. We recommend assigning LBC samples containing bizarre cells as ASC‐H with secondary diagnosis of LSIL.     

Comparison of SurePath® and ThinPrep® liquid‐based cervical cytology using positive predictive value,atypical predictive value and total predictive value as performance indicators

P. K. Wright, J. Marshall and M. Desai Comparison of SurePath ^® and ThinPrep ^® liquid‐based cervical cytology using positive predictive value, atypical predictive value and total predictive value as performance indicators Objective: Two liquid‐based cytology (LBC) systems are in widespread use in the UK: ThinPrep^® and SurePath^®. A number of studies have now compared LBC with conventional cytology in cervical screening. However, to date, we are aware of no studies that have compared ThinPrep^® with SurePath^® LBC. As the selection and use of specific diagnostic systems in a laboratory has significant clinical and economic implications, there is a clear need to compare directly existing LBC technology. The objective of this study was to compare ThinPrep^® with SurePath^® LBC in a single cytology laboratory using performance indicators. Methods: Data were collected for all cervical cytology samples processed at Manchester Cytology Centre over a 1‐year period. ThinPrep^® LBC was compared with SurePath^® LBC using positive predictive value (PPV), atypical predictive value (APV) and total predictive value (TPV), reflecting outcome of cervical intraepithelial neoplasia (CIN) grade 2 or worse for high‐grade dyskaryosis (PPV), low‐grade dyskaryosis or borderline (atypical) cytology (APV) and all (total) abnormal cytology (TPV). Results: 2287 (out of 56 467) (ThinPrep^®) and 586 (out of 22 824) (SurePath^®) samples showed borderline or worse cytology after exclusion criteria. PPV, APV and TPV were within acceptable ranges for both ThinPrep^® and SurePath^®. Conclusions: ThinPrep^® and SurePath^® were equivalent based on three performance indicators. We suggest that APV and TPV should be used as an adjunct to PPV and other methods of quality assurance for cervical screening.     

Histological examination of clots from cytological specimens: is this a worthwhile procedure?

A comparison of conventional cytology and clot histology was made on 174 serous fluids, fine needle aspirates (FNA) and other non‐gynaecological specimens. In eight cases (4.5%) this clot material contained malignant cells or cells suspicious of malignancy despite the absence of suspicious or malignant cells in conventionally prepared smears from the same specimen. In 11 cases (6.3%) the clot was negative, although conventional smears contained malignant or suspicious cells. A χ² test showed that there was no statistically significant difference between the number of positive diagnostic scores in each group with χ² of 0.223 (degrees of freedom=1), P=0.637. Examination of clot material from serous fluids and FNA aspirates is as effective as examination of conventional cytological preparations. Processing of clots from cytological aspirates for histological examination should be more widely adopted, and is applicable in all cytopathology laboratories.     

Utility of liquid-based cytology in endometrial pathology: diagnosis of endometrial carcinoma

Objective: The purpose of this study was to examine the utility of SurePath‐liquid‐based cytology (LBC) compared to conventional cytological preparations (CCP) in the identification of endometrial carcinoma. Methods: During a 13‐month period, direct endometrial samples were collected from 120 patients using the Uterobrush. The material comprised 30 cases each of endometrial carcinoma, proliferative endometrium, secretory endometrium and atrophic endometrium. The following points were investigated:(i) the frequency of cell clumps in endometrial carcinoma; (ii) the area of cell nuclei; (iii) overlapping nuclei. Results: (i) Comparison of the frequency of cell clumps with irregular protrusion pattern and papillo‐tubular pattern showed no statistically significant difference in either type of cell clump between CCP and LBC. (ii) Comparison of the nuclear area of cells showed a sequential decrease from endometrial carcinoma to secretory endometrium, to proliferative endometrium and to atrophic endometrium, which was significant in CCP and LBC. (iii) Nuclear area was significantly lower with LBC compared with CCP in endometrial carcinoma, secretory endometrium and proliferative endometrium but not atrophic endometrium. (iv) Comparison of the degree of overlapping nuclei showed a sequential decrease from endometrial carcinoma to proliferative endometrium, to secretory endometrium and to atrophic endometrium, which was significant in both CCP and LBC. (v) Comparison of the degree of overlapping nuclei between CCP and LBC showed no significant difference for normal types of endometrium, but LBC had significantly higher values (P < 0.0001) in endometrial carcinoma than in CCP. Conclusions: The results of this study revealed that applying diagnostic criteria used in CCP to LBC was easy to achieve, because LBC had excellent cytoarchitectural preservation and cells were well presented. Although we have not examined all cytological features of malignancy and have not considered atypical hyperplasia, we believe that this method may be a useful tool in the diagnosis of endometrial cytology.     

P-9A COMPARISON OF THE REPORTING MORPHOLOGICAL FEATURES OF GLANDULAR NEOPLASIA FOR CONVENTIONAL AND LIQUID BASED CYTOLOGY FOR CERVICAL SAMPLES

Cervical cancer accounts for approximately 15% of cancer diagnosed in women worldwide with up to 190 000 deaths per annum. One of the major causes of cervical cancer is the infection of human papillomavirus (HPV), a DNA virus. This virus is epidermotropic; there are over 75 subtypes and subtypes 16, 18, 31 and 33 are associated with cervical intraepithelial neoplasia (CIN) and carcinomas. Since the start of the cervical screening in mid 1960s, the cervical cancer rate has decreased. There are two techniques used for slide preparation and staining: conventional cytology and liquid based cytology (LBC). Due to the differences in sample collection and preparation, certain aspects of cell morphology, architecture and patterns will present differently from each other on the slide. The study was conducted in a County Hospital. Twenty conventional slides and eight LBC slides already reported as ? Glandular neoplasia were reviewed and assessed with regards to their morphological features. Moreover, conventional slides were compared with LBC slides to determine the differences in their cell morphology, sensitivity and specificity. Furthermore, a semi-quantitative method was used and also true-positive and false-positive rates were evaluated using positive predictive value (PPV). The findings indicated that despite the differences in cell morphology there are many similarities between the two techniques. The study also showed that it was difficult to distinguish between abnormal glandular cells and abnormal squamous cells, which may end in a false positive result and over reporting of glandular neoplasia. Finally, it showed that LBC slides were easier to screen and also had a higher positive predictive value (PPV) resulting in higher sensitivity and specificity. In conclusion, the LBC technique is more accurate and conversion to this technique is the positive step in the screening program.     

P‐4TRANSFORMATION ZONE COMPONENT IN LIQUID BASED CERVICAL CYTOLOGY

Introduction: Quality assurance guidelines for the UK cervical screening programme recommend that more than 80% of cervical samples from women aged 20–50 years should contain adequate numbers of Transformation zone (TZ) cells i.e. 10 or more endocervical or squamous metaplastic cells. This study was conducted to assess the frequency of TZ component in Liquid Based Cytology (LBC) both for ThinPrep (TP) and SurePath (SP) LBC. Also to assess the degree to which this is recorded by individual screeners and to determine the percentage of samples with evidence of TZ component for the different smear takers. Method: All LBC cervical specimens received at a tertiary cytology centre in the year 2004 from women aged 20–50 years were included in the study. Evidence of TZ sampling was recorded as: TP = TZ present (10 or more TZ cells)TA = TZ absentTS = TZ scanty (less than 10 TZ cells)TN = atrophic smears, TZ cells not recognisable Results: The total number of LBC cervical cases was 7445. TP = 4300 (mostly primary care) and SP = 3145 (mostly colposcopy). Overall TZ sampling rate in LBC was 82%. TP = 77.17%; SP = 88.24%. When scanty TZ was included, the standard was met for both systems (TP = 93.7%; SP = 88.24%). Presence/absence of TZ component was recorded in 6370 cases (85.1%); range 0%–97.79%. 56.7% of smear takers achieved the minimum standard for TZ sampling. Discussion: The percentage of ThinPrep samples containing adequate TZ cells was 77.17% compared to SurePath, which was 88.24%. This may be due to different patient populations i.e. primary care versus colposcopy. Screeners recorded TZ sampling in approximately 85% of samples. 56.7% of smear takers met the standard for TZ sampling.     

A comparison of variability in Papanicolaou and liquid-based cytology inadequacy rates using Shewhart control charts

OBJECTIVE: To use Shewhart control charts to compare variability in inadequacy rates from Papanicolaou (Pap) and liquid-based cytology (LBC). DESIGN: Retrospective analysis of quality assurance data. SETTING: Eleven Welsh cytology laboratories. METHODS: Shewhart 'p' charts were plotted for proportions of slides reported as inadequate. Charts were compared for statistical control. MAIN OUTCOME MEASURES: Evidence of statistical control in the processes. RESULTS: Control charts allowed easy interpretation of patterns in the data. Variability in inadequacy rates was much lower for LBC than for Pap cytology. CONCLUSION: Monitoring inadequate rates with Shewhart charts provides more information than tabular monitoring reports, assisting in quality improvement. With respect to inadequacy rates, LBC is less variable than Pap cytology.     

O‐12BLAND DYSKARYOSIS: A NEW PITFALL IN THINPREP® LIQUID BASED CYTOLOGY

Liquid based cytology (LBC) has improved cell visualization and preservation in cervical cytology. There has been a reduction in inadequate rate and some data to suggest an increase in sensitivity for dyskaryosis. Training for LBC has focused on differences in distribution of abnormal cells, but in most cases the morphological appearance of the dyskaryotic cells themselves is similar to that seen in conventional cytology. We are describing a new presentation of dyskaryosis which may be a cause of false negative cytology. We have referred to this as ‘Bland dyskaryosis’ because cells appear deceptively bland on low power examination, and can be misinterpreted as metaplastic or endocervical cells. Bland dyskaryosis cells are seen in groups. The architecture of the group is very disorganized, and adjacent cells show variation in size. Cells have a high nuclear/cytoplasmic ratio and smooth nuclear membranes. Chromatin is finely granular and evenly distributed. This is an unusual presentation of high‐grade dyskaryosis and we feel that there is a learning curve in laboratories converting to liquid based cytology. The spectrum of appearances of squamous dyskaryosis needs to be delineated to allow further increases in sensitivity for dyskaryosis.     

Is a liquid‐based cytology more sensitive than a conventional Pap smear?

K. Sigurdsson
Is a liquid‐based cytology more sensitive than a conventional Pap smear? Background: The comparative sensitivity of liquid‐based cytology (LBC) test and conventional Papanicolaou (Pap) smears is controversial. Material and methods: This study analyses the distribution of cytology, histology, colposcopy and large loop excision of the transformation zone among women screened in Iceland with LBC at the Cancer Detection Clinic in Reykjavik and with a conventional Pap smear outside the Detection Clinic in 2007–2011. The study material included 42 654 LBC tests from 20 439 women and 103 909 Pap smears from 61 574 women. The period 2000–2004 is used to correct for potential bias as a result of unequal distribution of the studied parameters between the study sites before the introduction of LBC. Results: The observed results indicated that women screened with an LBC sample had significantly decreased detection rates of inadequate smears, increased detection of low‐grade squamous intraepithelial lesion (LSIL)/atypical cytology and referrals to colposcopy, and an increased detection rate of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) irrespective of age. LBC increased significantly the detection rates of high‐grade squamous intraepithelial lesion or worse (HSIL+) cytology and CIN3+ histology only in women under 40 years of age. Taking into consideration the unequal prevalence of the studied parameters between the study sites in 2000–2004 indicated, however, that LBC only affected the rate of inadequate and low‐grade cytology tests under the age of 40 years. Positive predictive values for CIN2+ were not significantly different between the tests. Conclusions: The study results support the view that LBC is no more sensitive than Pap smears for the detection of HSIL+ and CIN2+ irrespective of age. LBC decreased the rate of inadequate smears, but increased the rate of low‐grade cytology under the age of 40 years and decreased the total rate of abnormal smears over the age of 40 years.     

Using a quality control approach to define an 'adequately cellular' liquid-based cervical cytology specimen

Objective:  To define a minimum acceptable total squamous cellularity for (ThinPrep^®) liquid-based cervical cytology (LBC) specimens using quality control techniques.
Methods:  Two hundred LBC preparations were made containing varying numbers (<200) of severely dyskaryotic squamous cells and with varying total cellularities.
Results:  Ninety-eight per cent of the LBC preparations that were missed by one or more of three cytoscreeners had fewer than 16 abnormal objects (single dyskaryotic cells or clumps of cells) and 87 dyskaryotic cells. The minimum ratio of dyskaryotic to total squamous cells that, in a preparation of 5000 squamous cells has a probability of at least 0.98 that 87 or more dyskaryotic cells will be present is 1 : 47. Twenty-three preparations diagnosed as abnormal had ratios of dyskaryotic to total squamous cells of between 1 : 2.5 and 1 : 4596. There is thus no feasible minimum acceptable squamous cellularity that will give an acceptable probability of detection of all specimen vials containing abnormal cells in the observed proportions.
Conclusions:  It is suggested that the minimum acceptable cellularity for LBC specimens is set pragmatically by the screening programme to give a feasible percentage of repeat tests.