Cervical smears in assessment of the natural history of human papillomavirus infections in prospectively followed women

The value of cervical (Papanicolaou) smears in monitoring the natural history of cervical human papillomavirus (HPV) infections was assessed in a series of 513 women prospectively followed since 1981. On each clinic visit, the patients were subjected to colposcopy accompanied by cervical smears and/or punch biopsies. The latter were analyzed by light microscopy for concomitant cervical intraepithelial neoplasia (CIN) and by transmission electron microscopy (TEM) for HPV particles as well as for HPV structural proteins. The stromal immunocompetent cell (ICC) infiltrates were phenotypically characterized using monoclonal antibodies for T-cell subsets, NK and K cells and Langerhans cells. HPV DNA typing was accomplished by Southern blot, spot and in situ hybridization using probes for HPV 6, 11, 16, 18 and 31. Lesions showing only changes consistent with HPV infection (HPV-NCIN) were associated with less severe atypia in cervical smears than were lesions with coexistent CIN (HPV-CIN). Normal smears were observed, however, in 24.7% of the cases with HPV-NCIN lesions, in 11.5% of cases with HPV-CIN I lesions but only exceptionally in cases with HPV-CIN II and III lesions (2.2% and 3.3%). The percentages of the different ICC phenotypes did not correlate with the atypia in cervical smears, but there was a shift towards the lower values of the T-helper/T-suppressor (OKT4+/OKT8+) cell ratio in parallel with increasing atypia. The possibility of latent HPV infection was suggested by the detection of viral particles, HPV antigens and HPV DNA in lesions shedding normal cells in the smears. The high-risk HPV types 16 and 18 were associated with the highest frequency of severely atypical cells; in the majority of cases, the low-risk types HPV 6 and 11 presented with less severe atypia. The first cervical smear seems to be of value as a predictor of the natural history of HPV lesions, as indicated by the fact that regression was inversely and progression directly related to initial cellular atypia. The present results confirm the intimate association between HPV infections and CIN. Although the biologic potential of the HPV infections seems to be dependent on multiple factors, routine cervical smears, because of their potential value in monitoring the natural history of this infection, should constitute an important means in the prospective follow-up of these patients.     

Cytophotometric analysis of corresponding cytological and histological cervical intraepithelial neoplasia grade III specimens

Cytophotometric analysis of cervical intraepithelial neoplasia grade III (CIN III) was performed in 22 cytological smears (CS) and in 22 corresponding cytospin specimens retrieved from selected areas of paraffin-embedded tissues (PEC). The average time interval between cytological and histological diagnosis was 6 weeks. CIN III nuclei in CS and PEC specimen were Thionin-Feulgen stained and digitized. Beside the visual classification of DNA ploidy patterns, the 2.5c and 5c exceeding rates and the specimen mean and standard deviation values of 21 photometric features were also analyzed. It was shown that, although there was a significant correlation between DNA ploidy patterns in corresponding PEC and CS specimen, the DNA patterns were dissimilar in eight of 22 cases. The DNA index, as represented by 2.5c and 5c exceeding rates, was significantly higher in the CS specimen. High-resolution cytophotometric analysis of cell nuclei in CS and PEC specimens showed significant differences for a large number of nuclear photometric features. These findings can possibly be explained by differences in selection of CIN III cells from CS and PEC specimens and by differences between fixation procedures as used for the two techniques. It was concluded that cytophotometric data of CS and PEC specimens representing CIN III lesions should not be regarded as interchangeable.     

Diagnostic and prognostic significance of image cytometric DNA ploidy measurement in cytological samples of cervical squamous intraepithelial lesions

D. Demirel, N. Akyürek and I. Ramzy
Diagnostic and prognostic significance of image cytometric DNA ploidy measurement in cytological samples of cervical squamous intraepithelial lesions Objective: To study the DNA ploidy pattern of uterine cervical squamous intraepithelial lesions (SILs) and its diagnostic and prognostic significance. Methods: The study included 31 cases of SIL: 11 low‐grade (LSIL) and 20 high‐grade (HSIL). Feulgen–pararosaniline staining was performed on previously Papanicolaou‐stained smears and a DNA image cytometric study was performed. An internal reference was used to calibrate the samples. Results: All 31 cases of SIL, either LSIL or HSIL, were non‐diploid. Of the 11 cases of LSIL, four were tetraploid and seven were aneuploid, whereas, of the 20 cases of HSIL, four were tetraploid and 16 were aneuploid. Stemline aneuploidy was not a significant discriminator between LSIL and HSIL (P = 0.32). Based on single‐cell analysis, HSIL cases had significantly higher DNA content than LSIL cases (P < 0.01). When a mean of 30% or more was used for the 6c‐exceeding event (6cEE) value, the sensitivity and specificity to indicate HSIL were 83% and 64%, respectively, with a positive predictive value (PPV) of 81% and negative predictive value (NPV) of 65%. All HSIL cases were cervical intraepithelial neoplasia grade 2 or worse (CIN2+) on biopsy. In addition, cases which showed recurrence had more DNA content by single‐cell analysis than those with an indolent clinical behaviour: P = 0.04 and P = 0.03 for LSIL and HSIL, respectively. Conclusions: Image cytometric DNA analysis is a useful technique for diagnostic and prognostic purposes in uterine cervical SIL when appropriate ‘c’ values are used in single‐cell analysis. We propose that a >6c DNA content of 30% is useful as a cut‐off level for predicting cases with CIN2+ in DNA image cytometry of cervical smears.     

Applicability of liquid-based cytology to the assessment of DNA content in cervical lesions using static cytometry

OBJECTIVE: To evaluate the nuclear DNA content of cervical lesions in liquid-based cytologic specimens prepared for static cytometry. STUDY DESIGN: The DNA content of cervical lesions was evaluated in cervical samples prepared with the Autocyte PREP liquid-based cytology system (TriPath Imaging Inc., Burlington, North Carolina, U.S.A.). A series of 47 samples stained with the Papanicolaou method (chronic cervicitis, n = 15; cervical intraepithelial neoplasia [CIN] 1, n = 25; CIN 2, n = 5; CIN 3, n = 2) were collected from consecutive women enrolled in an ongoing screening study at Leonor Mendes de Barros Hospital, S?o Paulo, Brazil, in 2002. Each residual sample was processed according to the Feulgen-thionin method (TriPath Imaging). Ploidy evaluation was performed using the CAS 200 image analysis system and Quantitative DNA Measurement software 3.0 (version 8.1) (Becton Dickinson, San Jose, Califoria, U.S.A.). Cellular ploidy was analyzed from atypical nuclei, and the DNA index was obtained using histograms for interpretation. RESULTS: All chronic cervicitis cases were diploid. Of the CIN 1 cases, 44% were diploid, 12% tetraploid, 32% aneuploid and 12% polyploid (diploid plus tetraploid). CIN 2 lesions were diploid in 60% and aneuploid in 40% of cases, whereas all CIN 3 lesions (100%) were aneuploid. CONCLUSION: The liquid-based cytologic samples proved to be suitable and highly useful for DNA analysis by image cytometry, which was capable of discriminating CIN 3 lesions from CIN 1 and 2 but not CIN 1 from 2 lesions. Aneuploidy was closely associated with CIN 3 lesions.     

Genome-wide methylation profiling identifies hypermethylated biomarkers in high-grade cervical intraepithelial neoplasia

Epigenetic modifications, such as aberrant DNA promoter methylation, are frequently observed in cervical cancer. Identification of hypermethylated regions allowing discrimination between normal cervical epithelium and high-grade cervical intraepithelial neoplasia (CIN2/3), or worse, may improve current cervical cancer population-based screening programs. In this study, the DNA methylome of high-grade CIN lesions was studied using genome-wide DNA methylation screening to identify potential biomarkers for early diagnosis of cervical neoplasia. Methylated DNA Immunoprecipitation (MeDIP) combined with DNA microarray was used to compare DNA methylation profiles of epithelial cells derived from high-grade CIN lesions with normal cervical epithelium. Hypermethylated differentially methylated regions (DMRs) were identified. Validation of nine selected DMRs using BSP and MSP in cervical tissue revealed methylation in 63.2–94.7% high-grade CIN and in 59.3–100% cervical carcinomas. QMSP for the two most significant high-grade CIN-specific methylation markers was conducted exploring test performance in a large series of cervical scrapings. Frequency and relative level of methylation were significantly different between normal and cancer samples. Clinical validation of both markers in cervical scrapings from patients with an abnormal cervical smear confirmed that frequency and relative level of methylation were related with increasing severity of the underlying CIN lesion and that ROC analysis was discriminative. These markers represent the COL25A1 and KATNAL2 and their observed increased methylation upon progression could intimate the regulatory role in carcinogenesis. In conclusion, our newly identified hypermethylated DMRs represent specific DNA methylation patterns in high-grade CIN lesions and are candidate biomarkers for early detection.     

Genome-wide methylation profiling identifies hypermethylated biomarkers in high-grade cervical intraepithelial neoplasia

Epigenetic modifications, such as aberrant DNA promoter methylation, are frequently observed in cervical cancer. Identification of hypermethylated regions allowing discrimination between normal cervical epithelium and high-grade cervical intraepithelial neoplasia (CIN2/3), or worse, may improve current cervical cancer population-based screening programs. In this study, the DNA methylome of high-grade CIN lesions was studied using genome-wide DNA methylation screening to identify potential biomarkers for early diagnosis of cervical neoplasia. Methylated DNA Immunoprecipitation (MeDIP) combined with DNA microarray was used to compare DNA methylation profiles of epithelial cells derived from high-grade CIN lesions with normal cervical epithelium. Hypermethylated differentially methylated regions (DMRs) were identified. Validation of nine selected DMRs using BSP and MSP in cervical tissue revealed methylation in 63.2–94.7% high-grade CIN and in 59.3–100% cervical carcinomas. QMSP for the two most significant high-grade CIN-specific methylation markers was conducted exploring test performance in a large series of cervical scrapings. Frequency and relative level of methylation were significantly different between normal and cancer samples. Clinical validation of both markers in cervical scrapings from patients with an abnormal cervical smear confirmed that frequency and relative level of methylation were related with increasing severity of the underlying CIN lesion and that ROC analysis was discriminative. These markers represent the COL25A1 and KATNAL2 and their observed increased methylation upon progression could intimate the regulatory role in carcinogenesis. In conclusion, our newly identified hypermethylated DMRs represent specific DNA methylation patterns in high-grade CIN lesions and are candidate biomarkers for early detection.     

Ploidy patterns in cervical dysplasia

The ploidy patterns determined for groups of patients with cervical dysplasia (cervical intraepithelial neoplasia [CIN]) were subjected to statistical analysis. The patterns were based on the measurement of at least 100 Feulgen-stained nuclei from 30 patients with normal cervices, 10 cases of CIN I, 18 cases of CIN II and 33 cases of CIN III. The scale of the patterns was a log transformation of the ratio of the total extinction (optical density) of the nuclei to that of the 2N reference; this widens the intervals for higher ploidies, alleviating sampling requirements for intervals in which occurrences are rare and helping to maintain a reasonable sample size-to-dimensionality ratio. Pairwise discriminant analyses showed clear distinctions between the ploidy pattern for normal cases and those for CIN I, CIN II and CIN III. The distinctions between the different grades of CIN, based on these modest sample sizes, were less clearcut, largely due to pronounced patient-to-patient variability. Analysis of variance confirmed that the patient groups constitute statistically distinct entities. An aneuploid pattern did not seem to develop until CIN III lesions were involved. The diagnostic and prognostic significance of these preliminary findings require further study using larger data sets and correlations to patient survival.     

Numerical chromosomal aberrations of chromosome 1 and 7 in dysplastic cervical smears

Cervical smears with Papanicolaou's staining (PAP) reveal only morphological characteristics of epithelial cells of the cervix uteri. Since chromosomal aberrations are known to play a role in malignant transition, we analyzed cervical smears for numerical changes of the chromosomes 1 and 7 with fluorescence in-situ hybridization to probe for a diagnostic value of these chromosomes in the characterization of cervical dysplasia. Cervical smears were collected from 21 patients with suspect histology of curettage or biopsy specimen, 14 of them having been subsequently graded as cervical intraepithelial neoplasia (CIN) III and 5 as CIN II. Nineteen normal cervical smears (PAP I-II) served as controls. Smears were hybridized with chromosomal enumeration probes for chromosome 1 and 7. Disomic cells (2 copies of chromosome 1 and 7) were decreased in the CIN II (63%) and CIN III group (57%) with respect to the control group (77%). Cells with 3 signals for chromosome 7 were significantly more frequent in the CIN III and the CIN II group than in the control group (6.7, 6.4 and 0.7%, respectively). Only the CIN II group (10%), but not CIN II (6%), showed a significant trisomy for chromosome 1 as compared with the controls (3.8%). A close correlation between the incidence of trisomy 1 or 7 and PAP grading was observed. PAP III-IIID smears with high trisomy 1 counts corresponded to CIN III histology, while all CIN II patients were PAP III-IIID with low incidence of trisomy 1. We conclude that trisomy of chromosome 7 is a feature of cervical dysplasia and seems to be an early event in dysplastic transition. In contrast, trisomy of chromosome 1 is observed only in high grade dysplasia and may be a marker for pre-malignant lesions.     

DNA ploidy and cytophotometric analysis of cervical intraepithelial neoplasia grade III and invasive squamous cell carcinoma

Cervical intraepithelial neoplasia grade III (CIN III) and squamous cell carcinoma (INV) were examined using DNA ploidy and cytophotometric analysis. Based on hysterectomy, exconisation, and biopsy material from 69 patients in two age categories, analysis was performed in nuclei isolated from selected areas of paraffin-embedded tissue. High percentages of DNA-diploidy in INV lesions were found mainly in the group of patients age 45 years or younger. CIN III lesions in women age 46 or older demonstrated high percentages of DNA-aneuploidy. DNA-polyploidy was most frequent in CIN III lesions in the younger age category. The results of cytophotometric analysis indicated that the overall mean values of 16 nuclear photometric features discriminated significantly between the whole groups of CIN III (n = 37) and INV (n = 32). On an individual patient level, however, the mean feature values showed a large overlap. Based on the results of a stepwise linear discriminant analysis of patient mean values, a combination of geometrical and run-length texture features was used to discriminate between CIN III and INV lesions. The correct classification rate was highest in the category of patients in the older age category. The results of this study indicate age related differences in CIN III and invasive squamous cell carcinoma, and they may be of help in assessing cytophotometric features in the study of progressive and non-progressive CIN lesions.     

Cervical screening: management of patients referred for colposcopy with smear abnormalities less severe than dyskaryosis

The cervical smear and biopsy results were reviewed for 141 patients who were referred for colposcopy with either a technically unsuitable smear or with cervical smear abnormalities less severe than dyskaryosis. The number of referrals due to minor smear abnormalities more than doubled from 8.6% to 22.3% of the total colposcopy referrals over the 4 year period studied. The minor smear abnormalities were only associated with cervical intraepithelial neoplasia (CIN) in patients aged <50 years. In 19 (13.5%) of the 141 patients high-grade lesions (CIN II or CIN III) were diagnosed. There were no cases of invasive cancer. Furthermore, the increased number of patients being referred for colposcopy with minor cervical smear abnormalities highlights the increasing pressures on colposcopy services, with prolonged waiting times for all patients.     

DNA changes in progressive cervical intraepithelial neoplasia.

Cervical intra-epithelial neoplasm (CIN) is treated as a progressive lesion, even though most CIN will not progress to invasive cancer if left untreated. This study focussed on DNA-cytometric analysis of cytologic smears of patients who had developed invasive cancer after initial smears showing CIN. The first part of the study aimed at describing the DNA-cytometric changes in these progressive ('malignant') CIN lesions. In the second part a cluster analysis was performed on 'malignant' CIN III lesions and CIN III lesions, with 'unknown' malignant potential. The results indicated that 'malignant' CIN lesions developed high DNA-index (DI) values during malignant transformation, as demonstrated by increasing mean DI values, a high percentage of DNA-aneuploidy and 2.5c Exceeding Rates. Furthermore, a trend-like pattern of texture feature values occurred in 'malignant' CIN lesions with increasing severity. These findings provide objective quantitative confirmation of the evolution of nuclear changes during malignant transformation. Cluster analysis showed that it was possible, using a set of four cytometric features, to subdivide the 'unknown' CIN III lesions into a cluster of lesions with feature values similar to the vast majority of the 'malignant' CIN III lesions, and a second cluster of lesions with feature values dissimilar to 'malignant' CIN III. It is argued that the profile of 'malignant' CIN has become clearer and that the results of this study may serve as a basis for a more objective cytopathologic subdivision of premalignant CIN. It may be justified to follow up patients whose lesions do not yet fit this 'malignant' profile. Not treating the non-progressive lesion group will avoid putting these patients at risk.     

Predictive value of DNA cytometry in CIN 1 and 2. Image analysis of 193 cases

OBJECTIVE: To investigate DNA image cytometry for predicting the prognosis of cervical intraepithelial neoplasia (CIN). STUDY DESIGN: Smears from 151 women affected by CIN 1 or 2 on cytology with minimal follow-up of three years were included. Sixty-seven showed progression, with histologically confirmed carcinoma in situ or invasive cancer. Eighty-four cases showed regression of the disease, which was cytologically, histologically and colposcopically confirmed. Papanicolaou-stained smears were destained, and the Feulgen reaction was performed with consecutive image DNA cytometry of suspicious cells using an image analysis system (Cires, Zeiss, Germany). The DNA index of the greatest stemline and the number of single aneuploid cells, using 9c exceeding events, were computed. RESULTS: In the group with progression, an aneuploid DNA stemline was found in 25 smears (26.9%). In 64 cases (66.7%) more than one aneuploid event was detected. The total number of aneuploid cases in this group was 76 (81%). In the group without progression, the number of aneuploid stemlines was 2 (2%). Single aneuploid cells could be found in five cases (5%). The overall number of aneuploid cases in that group was five. The sensitivity was 74.3%, positive predictive value 85.2% and negative predictive value 77%. CONCLUSION: Aneuploidy is a marker for prospective malignancy in cervical Papanicolaou smears. DNA image cytometry, as an additional method, can be used to predict outcome in patients with CIN 1 and 2 of the cervix. DNA cytometry is not a screening method but can add further information for a treatment decision in doubtful cases.     

Cytophotometric analysis of cervical intraepithelial neoplasia grade III, with and without synchronous invasive squamous cell carcinoma

Cytophotometric analysis was performed in nuclei retrieved from paraffin-embedded cervical tissue from 57 cases of CIN III. CIN III lesions of patients without invasive squamous cell carcinoma (N = 37) were regarded to represent a mixture of progressive and nonprogressive lesions. The CIN III lesions of patients with a synchronous invasive squamous cell carcinoma (N = 20) were regarded as representing truly progressive precursor lesions (CIN.INV). Twenty-one photometric features describing geometrical, density, and texture characteristics were extracted from the digitized nuclear images. Statistical analysis of cytophotometric data indicated significant differences between the group of CIN III lesions and CIN.INV lesions. A cluster analysis, using one co-occurrency texture feature (S-HOMOG), one density feature (S-DI), and two geometrical features (S-AREA and M-CIRC), showed that two clusters (C1 and C2) were present in the total group of CIN III and CIN.INV lesions. The vast majority of CIN.INV lesions was member of one and the same cluster C1. The CIN III group appeared to consist of a mixture of two clusters, 54% C1 and 46% C2 lesions. Of patients 45 years or younger, the majority (62%) of CIN III lesions had feature values, corresponding with those of cluster C1, and as such possibly with a potentially progressive course. In patients older than 45 years the percentage of CIN III lesions with C1 feature values was 27%.     

Clonality analysis of archival cervical smears. Correlation of monoclonality with grade and clinical behavior of cervical intraepithelial neoplasia

OBJECTIVE: To establish a polymerase chain reaction (PCR)-based clonality assay for archival cervical smears and examine its value in the detection of cervical intraepithelial neoplasia (CIN) and prediction of its clinical behavior. STUDY DESIGN: Dyskaryotic cells were microdissected from archival cervical smears of 33 cases and subjected to PCR-based clonality analysis of the androgen receptor gene. High-risk HPV subtypes were screened by PCR. RESULTS: Monoclonal patterns were found in 9/9 CIN 3 and 15/21 CIN 2, while polyclonal patterns were observed in the remaining 6 CIN 2 and 3/3 CIN 1. All patients with monoclonal CIN lesions, including 15 CIN 2, showed recurrence of the disease despite treatment. The original CIN 2 and recurrent CIN lesion in each of the 6 examined cases showed the same monoclonal pattern, suggesting a clonal link. In contrast, the patients with polyclonal CIN 1 or 2 became negative and remained disease free. High-risk HPV subtypes were found in all monoclonal CIN lesions, including 9 CIN 3 and 15 CIN 2, and in 4/6 polyclonal CIN 2 but not in CIN 1 lesions. CONCLUSION: Clonality analysis of cervical smears is potentially valuable in the identification of true neoplastic cells and prediction of clinical behavior of CIN 2 lesions.     

Comparison of DNA ploidy and nuclear size, shape and chromatin irregularity in tissue sections and smears of prostatic carcinoma

Image analysis measurements of nuclear size, shape, texture and DNA ploidy were compared in smears versus the corresponding 4-microns tissue sections, both prepared from radical prostatectomy specimens obtained from resections for prostatic cancer. Thirty-nine cases (78%) showed concordant DNA histograms between the smear and the tissue section. In six cases (12%), both preparations were nondiploid, but a tetraploid population was also present in one, but not both, of the preparations. In five cases (10%), there was a major discordance between the smear and the tissue section, with one preparation diploid and the other nondiploid. One source of discrepancy between the smear and tissue histograms was the overlapping of larger nuclei in tissue sections, which often precluded the analysis of the most atypical cells. Some tissue histograms were difficult to interpret due to wide coefficients of variation, irregular peaks and some shift from 2n in the diploid peaks. The best morphometric correlation (0.78) between the smears and the tissue sections was for the modal nuclear shape. Nuclear size and texture measurements showed poorer correlations. These findings suggest that cytologic preparations of prostatic carcinoma should be preferred for image analysis.     

Rapid review in cervical cytology: a retrospective review of cases detected on rapid review within a DGH cytology department and subsequent outcome

We retrospectively reviewed smears detected by rapid review within a district general hospital (DGH) laboratory over a period of 33 months and the subsequent histological or cytological outcome. Sixty-three cases had adequate follow-up data: 32 subsequently had two negative smears and 31 had a histological abnormality on subsequent biopsy. Twenty were high-grade lesions (CIN2, CIN3 or a glandular lesion) and eight of these were preceded by a low-grade smear abnormality. We reviewed and compared the pattern and distribution of smear abnormalities in these 63 cases. Abnormalities were often present within few cells (76%, n = 48 with 50 abnormal cells or less) or in micro-biopsies (27%, n = 17). There was no statistical difference in the pattern and distribution of smear abnormality between the rapid review-detected smears with a biopsy-proven abnormality and those with negative follow-up smears. Overall, the positive predictive value for high-grade CIN detected by rapid review (75%) was within NHSCSP achievable standards targets. This review of rapid review-detected abnormalities and the biopsy and cytological follow-up reiterates the importance of the method in cervical screening.     

Analysis of five sampling methods for the preparation of cervical smears

The quality of the cervical smear, a decisive factor in the efficacy of population screening, can depend on the sampling method utilized. An analysis was made of the performance of five sample takers in a screening program, each of whom had made approximately 5,000 smears, and of the five sampling methods each had used: spatula alone (method A), Cytobrush plus spatula (method B), Cytopick (method C), cotton swab plus spatula (method D) and Cervex brush (method E). The differences between the sample takers and the sampling methods were significant in both the detection of grade III cervical intraepithelial neoplasia (CIN III) (P less than .01) and in the production of smears containing endocervical cells (EC+) (P less than .018). The data obtained firmly establish the importance of the presence of endocervical cells for smear adequacy. The results of this study indicate that (1) method B (Cytobrush plus spatula) and method C (Cytopick) give superior results in the preparation of EC+ smears and in the detection of CIN III and thus should be used in population screening programs, and (2) methods A and D should not be used for cervical cytologic sampling in such programs.     

Efficacy of cotton-tipped applicators for obtaining cells from the uterine cervix for Papanicolaou smears

A study was made of the efficacy of two techniques for the preparation of Papanicolaou smears. In one technique ("swab-spatula technique"), a scraping of the endocervix with a saline-moistened cotton-tipped applicator was combined with a scraping of the ectocervix with a plastic spatula. In the second technique ("swab technique"), the endocervix and ectocervix were scraped with only a saline-moistened cotton-tipped applicator. The swab technique produced more inadequate smears with a scanty cellular yield (24/408 = 6%) than did the swab-spatula technique (9/361 = 3%). The swab technique also produced higher false-negative rates (60% for CIN I, 42% for CIN II, 16% for CIN III, 20% for invasive cancer, and 32% overall) as compared with those of the swab-spatula technique (27% for CIN I, 29% for CIN II, 14% for CIN III, 0% for invasive cancer and 18% overall). Because of the higher rates of inadequate samples and false negativity in smears prepared by cotton-tipped applicators alone, it is recommended that the spatula not be omitted in taking cervical samples for the preparation of Papanicolaou smears for the detection of dysplasia or cancer. This study also reflects a poor performance of a cervical cancer detection system in the setting of a major medical school and suggests the need for instruction and periodic evaluation of the performance of the staff taking the smears. This study also substantiates doubt on the value of a second recent smear as a follow-up procedure for cervical dysplasia.     

Estimating the sensitivity of cervical cytology: errors of interpretation and test limitations

The objective of this study was to estimate: (i) the sensitivity of cytologists in recognizing abnormal smears; (ii) the sensitivity of cervical cytology as a method of detecting abnormal smears among those obtained in the presence of cervical intraepithelial neoplasia (CIN). Study subjects were 61 women with a histologically confirmed CIN identified through colpohistological and cytologic screening. For objective (i) new smears were taken from study subjects just before treatment, mixed with routine preparations, interpreted by unaware cytologists and then blindly reviewed by a group of three expert supervisors, who reached a consensus diagnosis. Cytologists classified as positive for squamous intraepithelial lesion (SIL) 30 of the 34 smears judged as positive by supervisors (100% of smears classified as high-grade and 67% of smears classified as low-grade SIL by the supervisors). Our approach, based on creating a set of smears with a high a priori probability of being positive, proved to be an efficient way of estimating errors of interpretation. For objective (ii), smears taken at the moment of diagnosis, just before biopsy, were also reviewed by the same supervisors. These CIN cases were identified among asymptomatic women independently of cytological findings and results are therefore not subject to verification bias. Among the 33 histological CINII/III, four (12%) smears had no atypical cells (three negatives and one unsatisfactory) at review. The same proportion was 26% (four negatives and one unsatisfactory) among the 19 histological CINI. No significant differences in smear content were found between the seven ‘false negatives’ and a sample of ‘true positives’ and ‘true negatives’ for a number of formal adequacy criteria (including presence of endocervical cells). Strong differences were found between positive smears taken just before biopsy and those taken just before treatment (in 11 women the first smear only was positive, while the opposite was never observed), suggesting an effect of punch biopsy in removing lesions.     

Inflammatory atypia. An apparent link with subsequent cervical intraepithelial neoplasia explained by cytologic underreading

A review of 5,752 cervical smears done on college students at a medium-sized midwestern university in a 24-month period showed 496 cytologic diagnoses of inflammatory atypia and 132 of dysplasia (cervical intraepithelial neoplasia: CIN). Further retrospective review of a nonselected cohort (178 cases) of the 496 patients with inflammatory atypia showed that their subsequent cytologic smears were more likely to show CIN than could be explained by chance alone. Only ten cases accounted for this difference, and a case-controlled blind review of the original cytologic smears of these ten patients resulted in the reclassification to CIN (mild dysplasia) of seven who had subsequently "progressed" from inflammatory atypia to dysplasia. Only one control smear was reclassified. In this population, underreading of a small number of cervical smears explained a strong statistical apparent correlation between inflammatory atypia and the subsequent development of CIN.