A study of the effect of introducing a restrictive cervical screening policy on laboratory workload and cervical cancer detection rates

This study examines the effect of a change in screening policy on the detection rate of severe dyskaryosis. During 1987 a total of 423 cases of severe dyskaryosis were identified by the Avon Screening Programme. Eleven per cent of these abnormal smears were repeat smears taken without clinical indication within the recommended 5 year recall period (interval smears). In a comparable control group of negative smears 31% were interval smears. Twenty-five per cent of the dyskaryotic interval smears (3% of the total severely dyskaryotic smears) were taken within 3 years of the previous negative smear, compared with 50% of the control group. By discouraging opportunistic smears within 5 years of the previous smear, the laboratory workload could be reduced by 30%, or within 3 years of the previous smear by 15%. There is, however, a risk of 11% and 3% respectively of missing a significant lesion (severe dyskaryosis).     

Improving the NHS cervical screening laboratory performance indicators by making allowance for population age, risk and screening interval

OBJECTIVE: One of the key performance measures in the monitoring of the NHS cervical screening programme is the targeting of laboratories with very high or low percentages (outside the 10th-90th percentile) of adequate smears that have moderate dyskaryosis or worse. These laboratories are assumed to include those laboratories that may have extremes of sensitivity and specificity. A clear limitation with this methodology is that laboratories do not examine smears from women with the same underlying risk, age distribution or screening interval and adjustment for these factors should considerably improve the method. METHODS: This paper describes a method that allows for these confounding variables and a new age-risk-interval adjusted moderate dyskaryosis or worse rate (ARI-adjusted mod+ rate) can be calculated. The adjusted rate is the rate of moderate or worse dyskaryotic smears that the laboratory would have detected had it been screening women with an English 'average' age-risk-interval. All laboratories can therefore be compared using this method. RESULTS: The methodology is illustrated using data from the NHSCSP South West Region. The particularly low percentage of moderate or worse smears detected by one or two laboratories can be shown to be due to a local screened population with a very low risk because of a high mean age, relatively short screening interval and census variables associated with a low risk, rather than any under-calling by the associated laboratories. CONCLUSIONS: The ARI-adjusted mod+ rate requires to be calculated for all laboratories in England if it is to be used as a primary performance indicator. Alternatively, it can be used to further examine laboratories that are deemed to be outliers using the current methodology.     

Effect of circulation and discussion of cervical smears on agreement between laboratories

The study objective was assessing whether circulation of smears and discussion of those with differing interpretation can increase reproducibility between laboratories. The study included: the blind interpretation of a first set of 194 smears among seven laboratories, the discussion of smears with discrepant diagnoses during the previous phase and the blind interpretation of a second set of smears of same size and characteristics. After discussions, the overall weighted kappa increased in five laboratories (substantially in three : +50%, +27% and +20%). However, no change was observed in one laboratory and a slight decrease (-4%) in another. The latter interpreted the second set of smears at a longer time interval from discussions. Agreement improved for all diagnostic classes except low grade intraepithelial neoplasia (LSIL). Overall, the intervention increased diagnostic agreement, but its effect varied with laboratory and by diagnostic class and could be transient. Continued programmes of smear exchange and discussion appear to be advisable.     

Review of negative and low‐grade cervical smears in women with invasive cervical cancer after the first 3 years of the national cervical screening programme in Slovenia

A. Repše‐Fokter, A. Pogačnik, V. Snoj, M. Primic‐Žakelj and M. S. Fležar
Review of negative and low‐grade cervical smears in women with invasive cervical cancer after the first 3 years of the national cervical screening programme in Slovenia Objective: The purpose of the study was to perform a national review of negative, low‐grade and inadequate smears reported during the latest screening period before cervical cancer diagnosis in 2006, after the first 3 years of the screening programme. Methods: Among 162 new cervical cancer cases there were 47 (29%) without previous cytology, 47 (29%) with one high‐grade smear prior to diagnosis and 68 (42.0%) with at least one previous negative, low‐grade, atypical or inadequate smear 1–40 months before diagnosis. Of the latter 68 cases, 37 patients with 59 smears (together with 118 control slides) were included in the review as 31 had smears reported at laboratories no longer operating. Findings were related to the last cytology report before diagnosis as well as to histological type and stage of the cancer. Results: In our study group, 19 (51%) of 37 patients had squamous cell carcinoma, 15 (41%) adenocarcinoma and 3 (8%) adenosquamous carcinoma, compared with 121 (75%), 26 (16%), 12 (7%), respectively, and 3 (2%) other types, for all carcinomas. Twenty‐one of 37 women also had high‐grade cytology prior to diagnosis of cancer. Women with previous cytology (with or without recent high‐grade smears) were more likely to have stage I cancers than those without cytology (P < 0.0001). The expert group upgraded 17/33 smears in the patients with squamous carcinomas, which was more than in those with adeno‐ and adenosquamous carcinomas (5/24, P < 0.05). Conclusion: As expected, a higher proportion of smears preceding adenocarcinomas were true negative. Under‐diagnosed smears were not related to cancer stage or last cytology report before diagnosis.     

The use of digital images to evaluate the interobserver agreement on cervical smear readings in Italian cervical cancer screening

G. Tinacci, A. Biggeri, A. Pellegrini, M.P. Cariaggi, M.L. Schiboni and M. Confortini The use of digital images to evaluate the interobserver agreement on cervical smear readings in Italian cervical cancer screening Objective: The aim of this study was to measure interobserver agreement among cytologists on using a set of digital images. Methods: A set of 90 selected Papanicolaou‐stained cervical smears were digitalized and the digital images circulated among 117 readers, from laboratories spread across almost all Italian regions. Three representative fields of each smear were displayed at 20× and 40× magnification (overall six images for each case). The diagnoses made by the cytologists who provided the images were taken as target diagnoses. Results: The κ values were: very low for the categories atypical squamous cells of undetermined significance (ASC‐US), and atypical squamous cells – cannot exclude high‐grade squamous intraepithelial lesion (ASC‐H); poor for the categories atypical glandular cells (AGC), high‐grade squamous intraepithelial lesion (HSIL) and invasive cancer; and fair to good for the categories negative and low‐grade squamous intraepithelial lesion (LSIL). However, we found a cluster of 42 best concordant readers. The overall κ value and overall weighted κ with the target diagnosis for these 42 readers were 0.45 and 0.66, respectively. This finding is in contrast with the overall κ value and overall weighted κ for the other readers of 0.39 and 0.59, respectively. Conclusions: As this finding is an estimate of the accuracy of the readers, we can infer that it will be very important to reach this level of concordance for all the participating readers. Future effort will facilitate common experiences in order to improve the reproducibility of diagnostic criteria. Digital images could be the key to reach this aim.     

The preparation of additional smears from a cervical scrape: impact on the rate of detection of cervical neoplasia

The preparation of additional smears from a cervical scrape: impact on the rate of detection of cervical neoplasia It has been known for some time that only a proportion of the cells on the smear-taking device is transferred to the slide. This can give rise to errors in reporting although the smear may have been taken correctly. This study was undertaken to identify a quick and simple method of improving the accuracy of the Papanicolaou test. A conventional smear and five additional smears were obtained from 62 women attending a Genito-Urinary Medicine clinic. The cell content of the conventional smears and the additional smears was compared. Dyskaryotic cells were detected both in the conventional smear and in the first and second additional smears from 22 women. Dyskaryotic cells were detected in the first and second additional smears only in five women. Thus, the conventional smear failed to detect biopsy-confirmed cervical abnormality in these women. A cell count of the first additional smear in the five cases where the conventional smear was negative showed that they contained, on average, 310 dyskaryotic cells. The preparation of one additional cervical smear per cervical scrape could significantly increase the accuracy of the cervical smear test by 11% (P=0.025, McNemar's test).     

Prospective study of PAPNET: review of 25656 Pap smears negative on manual screening and rapid rescreening

In this prospective study, 27,014 Pap smears were selected for PAPNET review on the request of the referring practitioner or patient. Smears that were negative on routine manual screening were submitted for rapid rescreening. Smears considered normal after these two manual screens (n = 25,656) were reviewed using the PAPNET testing system. Routine manual screening identified 1340 (4.96%) of the smears as abnormal, and a further 18 (0.07%) abnormalities were detected by rapid rescreening. PAPNET review identified an additional 102 (0.4%) abnormal smears, including 10 histologically confirmed high grade lesions. The use of PAPNET testing following routine manual screening and rapid rescreening in tandem, enables cytologists to detect additional diagnostically significant abnormalities and reduce the rate of false-negative smears.     

Quality assurance in cervical cancer screening

Objectives. to examine the effectiveness of introducing External Quality Assessment (EQA) into all laboratories which undertake gynaecological cytopathology. to assess pathologists and cytotechnologists regularly for their competence to screen cervical smears, regardless of their standing in the laboratory hierarchy or their experience of gynaecological cytopathology.
Methods. Each participant was asked to screen and report on 10 slides during a 2 h period. the assessment was carried out by a facilitator under the direction of a specially appointed EQA Committee. A maximum score of 20 points was awarded for a completely correct set of answers. A minus score was awarded for a missed abnormal smear. Seventeen pathology laboratories in North West Thames Regional Health Authority participated; 146 cytologists were assessed.
Results. A pilot and four rounds of EQA have been completed and a total 5350 smears examined. Out of 2568 dyskaryotic (abnormal) smears screened, 0.7% were not identified correctly. of the 146 cytologists taking part in the assessment, 95% achieved a score of 17 or more. Three participants were identified who did not reach an acceptable level of competence and appropriate remedial action was taken.
Conclusion. the EQA scheme detected unacceptable levels of performance which can be quickly rectified. Participation of 100% has been maintained on a voluntary basis, and 4 years experience of the scheme confirms that a very high standard of screening prevails in the Region. the study illustrates that voluntary self-regulation is acceptable in the NHS, and the introduction of similar EQA schemes on a national scale will go a long way to establishing confidence in the cervical cancer screening programme.     

Monitoring and evaluating the performance of the UK NHS Cervical Screening Programme: monitoring performance by using cytology outcomes adjusted for population characteristics

Current quality assurance measures used in the NHS cervical screening programme (NHSCSP) include a review of laboratories with percentages of moderate/severe and borderline/mild smear results outside the 10th-90th percentiles. The method is limited by the fact that many of these outlier smear percentages may reflect laboratories covering populations with low or high risk and/or short or long average screening intervals. This paper outlines a new approach to aid the detection of outlier laboratories, by using data collected at the primary care trust (PCT) or health authority (HA) level and making allowances for population characteristics and screening interval. The setting is the NHSCSP in England using annual data provided by HAs. Data from the screening year 2000-01 is used to illustrate the methodology, although the methods can also be applied to data at the PCT level (now being collected for 2002-03 onwards). Percentages of smear results have been analysed against a series of explanatory variables using logistic regression models. These explanatory variables include Townsend deprivation index, uptake-corrected ethnic minority composition, a measure of screening interval, area type and region. An expected percentage of borderline/mild and moderate/severe smears is estimated from the models and an observed : predicted ratio (OPRmod/sev and OPRbord/mild) calculated. Low values are suggestive of relative undercalling and high values overcalling, after allowance for population characteristics. Analysis of data for 2000-01 showed that the OPRmod/sev for the 99 HAs varied from 0.68 to 1.44. Laboratories with low percentages of moderate/severe smears, but associated with PCTs or HAs with OPRmod/sev values closer to unity may not need to be investigated as their observed rates are consistent with predicted rates based on population characteristics. The method could also be directly applied to laboratories if further information on the population covered by each laboratory were routinely collected.     

Borderline nuclear change; can a subgroup be identified which is suspicious of high‐grade cervical intraepithelial neoplasia,i.e. CIN 2 or worse?

Borderline nuclear change; can a subgroup be identified which is suspicious of high‐grade cervical intraepithelial neoplasia, i.e. CIN 2 or worse? Only 10% of first borderline smears are associated with a histological high‐grade (HG) abnormality, i.e. CIN 2,3, invasive malignancy or glandular neoplasia on subsequent investigation. The advantages of highlighting this subgroup are obvious but is this possible? From 1996 and 1997, 242 borderline smears with histological follow‐up were examined by two independent experienced observers (observer 1 and 2) without prior knowledge of further investigation results. For each smear a profile of nuclear details was produced, also noting the type of cell mainly affected by the process; then the observers were asked to assess the degree of worry of HG disease for each smear i.e. whether the smear fell into group 1 borderline changes indicative of low‐grade (normal, inflammatory, CIN1/HPV) disease (BL/LG) or group 2 difficult borderline smear, HG disease (CIN 2,3, invasive neoplasia or glandular neoplasia) cannot be excluded (BL/HG). Observer 1 selected a group of BL/HG with a PPV for HG disease of 38%, with observer 2 having a PPV of 50%; this compared with the overall laboratory HG disease PPV for borderline smears of 14%. Both observers found the most useful criterion to be the increase in nuclear:cytoplasmic ratio. Our results show that it is possible to separate a small group of borderline smears which should be classified as ‘borderline/high grade lesion difficult to exclude’ (BL/HG). Both observers had some success in arriving at this classification although their method of selecting out this group was quite different.     

Pap smears in women with endometrial carcinoma

OBJECTIVE: To correlate Pap smear findings with the histology of endometrial carcinoma and stage of the disease. STUDY DESIGN: Between 1995 and 1998, 76 women with endometrial carcinoma, having had Pap smears done within two to three months of hysterectomy at Memorial Sloan-Kettering Cancer Center, formed the basis for this study. All Pap smears and histologic sections were reviewed. RESULTS: Thirty-four patients had normal Pap smears (45%), and 42 had abnormal ones (55%). The mean age of the two groups was 65.1 and 65.2 years, respectively. Histologic subtypes included 44 International Federation of Gynecology and Obstetrics (FIGO) grade 1 endometrioid adenocarcinoma (low grade) and 32 high grade carcinomas, including 19 FIGO grade 2 or 3 endometrioid adenocarcinomas, 5 papillary serous carcinomas (PSC), 2 clear cell carcinomas (CC), 1 adenosquamous carcinoma, 3 endometrioid adenocarcinomas mixed with PSC and 2 endometrioid adenocarcinomas mixed with CC. The proportions of patients with low and high grade tumors with abnormal Pap smears were 43% (19/44) and 72% (23/32), respectively (P=.01). The proportions of patients with abnormal Pap smears and no myometrial invasion, invasion of <50% and >50% myometrial thickness were 40% (8/20), 62% (26/42) and 57% (8/14), respectively (P =.27). Vascular invasion was identified in 56% (9/16) of patients with abnormal Pap smears and in 55% (33/60) of patients with normal ones (P = .93). The proportions of patients having abnormal Pap smears with stage I and stages II, III or IV disease were 48% (30/62) and 86% (12/14), respectively (P =.01). CONCLUSION: Although the Pap smear is not a sensitive screening test for endometrial cancer and a negative Pap smear does not rule it out, this study revealed that abnormal Pap smears are significantly associated with high grade of tumor and stage II-IV endometrial carcinoma. However, they are not associated with patient age, depth of myometrial invasion or vascular invasion.     

Outcome of women referred to colposcopy for persistently inadequate smears

The outcome of referral to colposcopy of 240 women who had persistently inadequate smears was investigated. Of 232 women who attended colposcopy, 214 (92.2%) had a normal outcome, 12 (5.2%) had low grade abnormalities, and six (2.6%) had high grade abnormalities. This group of women therefore has a negligibly increased risk of harbouring cervical neoplasia. Although not directly comparable, women with a history of previous abnormal cytology did not have a higher risk than those without such a history. Unnecessary colposcopy could have been avoided in the majority of cases if a good quality repeat smear had been taken. Improved smear taker training could decrease the number of referrals. A hospital cytology clinic is proposed as a cost-effective alternative to colposcopy at the first attendance.     

Survey of smear taking practice in the former North Thames region

One hundred and seventy-seven doctors and 161 nurses from 230 clinics responded to a questionnaire on smear taking practice. The responses show that 66% of smear takers use the Aylesbury spatula and 30% use the Ayre spatula. A total of 53% use a cytobrush for selected cases. Training of smear takers and preparation of smears was satisfactory. Most (but not all) smear takers routinely record clinical information on the request form. Only 20 cytology laboratories in the North Thames region (70%) provide additional feedback to the smear takers about the quality of their smears apart from the information on the request form. Our study shows that feedback is an area where interaction between the laboratory and smear taker could be encouraged.     

Accuracy of thin-layer cytology in patients undergoing cervical cone biopsy

OBJECTIVE: To compare the accuracy of thin-layer cytology with Autocyte PREP (TriPath Imaging Inc., Burlington, North Carolina, U.S.A.) with conventional smears in 500 women undergoing cervical cone biopsy. STUDY DESIGN: The study was performed among 500 consecutive women presenting for cone biopsy for high grade cervical intraepithelial neoplasia (CIN) on biopsy in 350 (70%) and discrepant cytology/colpohistology in 150 (30%). Before performing a cone biopsy, two cervical samples were collected for conventional smears and thin-layer cytologic slides, with randomization of the order. Conventional smears were stained and diagnosed at Pasteur Cerba, while thin-layer cytologic slides were processed at a local TriPath office (Meylan, France) and sent in a masked fashion for screening at Pasteur Cerba. Any slides initially read as normal were reviewed again and reported without knowledge of the other cytologic or cone biopsy data. The final cytologic diagnoses for the two methods were compared with histopathology of the cone biopsy. RESULTS: The conventional smear was unsatisfactory in 58 (11.6%) of cases, while there were 4 (0.8%) unsatisfactory thin-layer cytologic slides (P < .001). Endocervical cells were missing from 31 (6.2%) of conventional smears and 34 (6.8%) of thin-layer cytologic slides. For the pooled data, sensitivities of conventional smear and thin layer for detecting high grade CIN (0.82% and 0.86%, respectively) were similar as were specificities (0.40% and 0.43%, respectively). When first samples were compared, the sensitivities of the conventional smear and thin layer for high grade CIN were 0.79% and 0.89%, respectively (P = .02), with corresponding specificities of 0.41% and 0.36% (P < .01). CONCLUSION: When controlled for sample order, the sensitivity of thin-layer cytology for detecting high grade CIN was significantly higher than that of conventional smears in patients with previous abnormal cytology, but at the expense of specificity.     

The use of screening episodes linked to CIN3 and invasive cancer registrations to study outcomes from the NHS Cervical Screening Programme

Objective: To examine how NHS cervical screening data can be collected and analysed in order to evaluate women’s screening histories as episodes rather than as individual smears. Design: Analysis of routine cervical screening data grouped into screening episodes for a cohort of women regarding episodes starting in a given year. Setting: NHS Cervical Screening Programme. Population: Data from four Health Authorities (now eight Primary Care Trusts) from the NHS Cervical Screening Programme with primary smears (first in an episode) taken between 1 April 1999 and 31 March 2000. Methods: Cytology information obtained from the call/recall (‘Exeter’) computer system was linked to cervical intraepithelial neoplasia (CIN) 3 and invasive cancer outcome information obtained from cancer registries. Screening histories were divided into episodes, each starting with a primary smear that was followed up to episode closure or, for episodes still open followed for an average 4.25 years, from the primary smear. The episode was divided into two parts (up to referral to colposcopy and following the referral). The outcomes of the episodes are described including referral rate to colposcopy and CIN3 and invasive cancer rates by factors such as age. Main outcome measures: Episode histories and rates of referral to colposcopy, CIN3 and invasive cancer. Results: There were 176 923 episodes from 176 319 women (1.003 episodes per woman) followed up to March 2004, the date at which the first phase of information accrual ceased. Of these episodes, 172 100 (97.3%) were closed either by a negative smear referring the woman back to routine recall or by default (defined as no smear recorded within 21 months following a smear requiring an action of repeat or refer to colposcopy). The remaining 4823 (2.7%) of episodes were still open, of which in 3121 (1.8%) the woman had been referred to colposcopy and in 1702 (1.0%) no referral decision had been made. Referral rates to colposcopy varied by age from 5.7% in women aged 20–24 years down to 0.9% in women aged 60–64 years. The overall efficiency of screening was highest for woman aged about 30 years, with a CIN3 detection rate of eight per 1000 women and a positive predictive value (for CIN3 or worse) of referral to colposcopy of 21%. Conclusion: The study has shown that routinely collected NHS cervical screening data can be combined to give information on complete episodes, allowing important performance measures to be studied. We suggest that in future information in the NHS screening system should be structured to facilitate such analysis and to allow cytology and histology information to be readily linked.     

Performance of a new, liquid-based cervical screening technique in the clinical setting of a large French laboratory

OBJECTIVE: To compare the performance of liquid-based cytology with the CYTO-screen System (SEROA) with that of conventional smears through a secondary analysis of a large database covering the activity of an independent French laboratory during the period 1998-2002. STUDY DESIGN: The study was performed with a retrospective, comparative, historical design on 2 subgroups of women having been screened by gynecologists who switched from conventional smears to the CYTO-screen System in the period 1998-2002. The first cohort population consisted of women who had at least 4 subsequent screening tests over the period with half conventional and half with the CYTO-screen System. A control group consisted of smears collected by gynecologists who fully maintained activity with a conventional method over the same period. The second group consisted of women who had their first screening test performed over the study period by gynecologists who modified their technique. Specimen adequacy, endocervical cell content and epithelial cell abnormality detection rates were compared between the groups. RESULTS: As compared with the conventional smear, the CYTO-screen System showed a reduction in unsatisfactory reports, especially in the second group of first-screened (0.14% versus 1.3%, P < .0001). The rate of atypical squamous cells of undetermined significance increased significantly after the switch to the CYTO-screen System (2.5% versus 1.3%, P = .004) and in the second group of first-screened women (2.05% versus 1.4%, P = .0014), with higher histologic confirmation in both situations. There was a non-significant increase in the detection rates of low and high grade squamous intraepithelial lesions after the switch to the CYTO-screen System and in the second group of first-screened women. CONCLUSION: The CYTO-screen System gives higher-quality specimens and has a higher detection rate for squamous intraepithelial lesions, but that rate was significant only for atypical squamous cells of undetermined significance.     

The cervical smear test: does timing have an effect on sample adequacy?

OBJECTIVE: The aim of this study was to determine the effect of timing of the cervical smear test on sample adequacy. METHODS: Inadequate and negative smears from pre-menopausal women, with a regular menstrual cycle and who were not undertaking any hormone therapy, were selected and re-screened. The inadequate smears were then categorized according to the reasons for the inadequate result. The time of the cycle that the smear was taken was recorded for both inadequate and negative smears. The expected frequency of smears per phase was compared with the observed frequency per phase using the chi-squared statistical test. RESULTS: There was no significant difference between the overall observed and expected rate of the inadequate smears of nine general practitioner (GP) practices (P = 0.886), of GP practice 4 (lowest inadequate rate) (P = 0.610), or GP practice 6 (highest inadequate rate) (P = 0.621) at any phase of the cycle. CONCLUSION: Results show that there is no optimum phase for adequate sample collection, therefore it is suggested that there is no effect of timing of the cervical smear test on sample adequacy, that timing is not a relevant factor in reducing the inadequate smear rate, and restricting smear taking to mid-cycle is unnecessary. (The information regarding last menstrual period/length of cycle from which these conclusions were reached relied upon the accuracy of patient information given to the smear taker.).     

Should the laboratory assess the sampling adequacy of cervical smears?

Should the laboratory assess the sampling adequacy of cervical smears? The results of a questionnaire answered by 14 out of the 18 NHS laboratories in Scotland reporting cervical smears showed that, since the publication of Guidelines for Judging the Adequacy of a Cervical Smear, by the British Society for Clinical Cytology (BSCC), rates of unsatisfactory smears had risen from a mean of 3.3% to 6.5%, with some laboratories reporting rates of over 10%. Four laboratories followed the guidelines closely in requiring the presence of two indicators of sampling of the transformation zone, i.e. endocervical cells, metaplastic cells or endocervical mucus. Seven laboratories required one indicator either in all smears or in a subset, whilst three did not require any indicator at all. The laboratories observing the guidelines closely had a higher mean unsatisfactory rate than those partially observing them. The main impediment to the full implementation of the BSCC guidelines appeared to be fear of an unmanageably high unsatisfactory smear rate. The accuracy of the assessment of adequacy is questioned, as is the cost effectiveness of doing so.     

Conventional Pap smear and liquid-based cytology as screening tools in low-resource settings in Latin America: experience of the Latin American screening study

OBJECTIVE: To evaluate the performance of the conventional Pap test and liquid-based cytology (LBC) in an ongoing multicenter trial testing optional screening tools (cytology, screening colposcopy, visual inspection with acetic acid, visual inspection with Lugol's Iodine, cervicography and Hybrid Capture II [HCII] (Digene Brazil, S?o Paulo, Brazil) conventional and self-sampling), for cervical cancer in Brazil and Argentina. STUDY DESIGN: A cohort of 12,107 women attending four clinics (Campinas, S?o Paulo, Porto Alegre, Buenos Aires) were randomized into the 8 diagnostic arms. Women testing positive with any of the tests were referred for colposcopy, and cervical biopsies were used as the gold standard to assess performance characteristics of the diagnostic tests. Conventional Pap smears were sampled by all clinics (n = 10,240), and LBC (Autocyte PREP, [TriPath Imaging, Burlington, North Carolina, U.S.A.], n=320, and DNA-Citoliq [Digene Brazil], n =1,346) was performed by 1 of the clinics. RESULTS: Conventional Pap smears showed no squamous intraepithelial lesions (normal) in 8,946 (87.4%) and LBC in 1,373 (82.4%). Using high grade squamous intraepithelial lesions (HSIL) as the cutoff, Pap smears predicted high grade (cervical intraepithelial neoplasia [CIN] 3) with OR 63.0 (95% CI, 36.90-107.70), standard error (SE) 59%, SP 97.8%, positive predictive value (PPV) 68.1% and negative predictive value (NPV) 96.7%. The same figures for Autocyte PREP were: OR 9.0 (95% CI, 2.43-33.24), sensitivity (SE) 33.3%, specificity (SP) 100%, PPV 100% and negative PV (NPV) 88.8%. DNA-Citoliq detected CIN 3 as follows: OR 11.8 (95% CI 2.60-53.26), SE 40.0%, SP 94.6%, PPV 40.0% and NPV 94.6%. Lowering the cutoff to low grade squamous intraepithelial lesions increased SE and NPV but compromised SP and PPV. The detection rates for high grade lesions after an atypical squamous cells of undetermined significance diagnosis were similar with the 3 techniques. In our settings, the 3 methods of cervical cytology were slightly different in performance. The conventional Pap smear had the highest SE, while Autocyte PREP had 100% SP and PPV in detecting CIN3 with the HSIL cutoff. All 3 tests had lower SE but higher SP as compared to HCII.     

A pilot study of cervical screening in an inner city area—lessons for a national programme

The objectives of this study were to examine aspects of organization of a proposed national screening programme based in general practice. The target population of women aged 25–59 years and their general practitioners (GPs), in a defined inner city area, was identified from a population register of persons eligible for free medical services; a computerized system was developed for invitations and record linkage of cytology results. Smears were examined in one laboratory and follow up of women with abnormal smears was undertaken by one gynaecologist. A random sample of non‐responders was surveyed by questionnaire. Response following two invitations was only 20%. Practices with male doctors only had significantly lower reponse rates ( P <0.001) than those with a female doctor/nurse. A survey of non‐responders showed that over 20% of addresses were incorrect and 16% of those interviewed were ineligible for smear tests. A preference for a female to undertake smears was expressed by 67%, and 77% believed that the purpose of the cervical smear was to detect cancer. An accurate population register, health promotion, support for GP practices, provision of alternative venues for smear tests, development of computer systems, accurate data entry and fail‐safe follow up are aspects of a cervical screening service which must be addressed prior to setting up a national service.