False-negative results in cervical cytologic studies

The appropriate interval between cervical cytologic screening studies is a matter of considerable controversy, with a major consideration being the problem of false-negative results. To determine the rate of false-negative cervical cytologic results in our laboratory and to determine how these failures occur, tissue-proven cases of carcinoma in situ, invasive squamous-cell carcinoma, endocervical adenocarcinoma and lymphoid malignancy involving the cervix with negative Papanicolaou smears obtained within one year prior to the tissue diagnosis were reviewed. Over the four-year period from 1980 through 1983, 339 patients had tissue-proven cervical malignancies. Of these, 66 had false-negative Papanicolaou smears, representing a 20% overall false-negative rate. These false-negative smears were rescreened. For all types of cervical malignancy, the majority of errors were due to sampling. No malignancy was missed disproportionately by either cytotechnologists or cytopathologists. We plan to utilize these data for quality control purposes and for continued review of future performance.     

Atypical glandular cells of undetermined significance on cervical smears. A study with cytohistologic correlation.

OBJECTIVE: The incidence of endocervical adenocarcinoma has increased steadily over the past two decades. Since the Bethesda System was introduced, the diagnosis of atypical glandular cells of undetermined significance (AGUS) has also risen and now accounts for 0.46-1.83% of all cervical (Pap) smears. The purpose of this study was to evaluate the significance of a diagnosis of AGUS using cytohistologic correlation. STUDY DESIGN: A retrospective review of archival material from 1993 through 1996 identified 64 patients who had smears diagnosed as AGUS and had a subsequent surgical biopsy. The smears were reviewed and cytologic features analyzed and correlated with the histologic diagnosis. RESULTS: On biopsy, 3 (5%) of the 64 cases showed endocervical adenocarcinoma in situ (AIS) (1 case with invasive adenocarcinoma also), 14 (22%) had a benign glandular lesion (endocervical polyp, tubal metaplasia, microglandular hyperplasia, reactive changes), 35 (54%) had squamous intraepithelial lesion (SIL) (15 diagnosed on the original smear), and 12 (19%) had no abnormality. Among the cytologic criteria evaluated, feathering (P = .01), palisading (P < .001) and chromatin clearing (P = .002) were shown to have a significant association with the histopathologic diagnosis of AIS/adenocarcinoma. These features were also useful in distinguishing AIS/adenocarcinoma from SIL and benign glandular changes from AIS/adenocarcinoma but not benign/reactive glandular changes from SIL. CONCLUSION: A diagnosis of AGUS correlated with a clinically significant lesion in the majority of cases. Squamous dysplasia (SIL) was the most common lesion identified. The presence of feathering, nuclear palisading and chromatin clearing increased the likelihood of a histologic diagnosis of AIS/adenocarcinoma.     

Use of the Cytobrush for cervical sampling after cryotherapy

The presence of endocervical cells in routine gynecologic smears (prepared from spatula and cotton swab samples) and Cytobrush smears was analyzed in 52 patients with a history of prior cryotherapy. These cases represented 11% of the 491 women evaluated using both techniques between August 1, 1987, and January 31, 1990. The routine smear contained endocervical cells in 25 (48%) of the 52 cases while the Cytobrush smear contained endocervical cells in 49 (94%) of the cases. The use of the Cytobrush for cervical cytologic screening thus appears to be of value in patients with a prior history of cryotherapy, which frequently renders the transformation zone less accessible to routine sampling.     

Intraobserver and interobserver variability in the quality assessment of cervical smears

Intraobserver and interobserver variability in assessing the quality of cervical smears, as measured by the presence or absence of endocervical columnar cells and squamous metaplastic cells, was evaluated. In total, 180 cervical smears representing the most important cytologic diagnoses were anonymously rescreened twice by 19 observers with an interval of six months. An absence of endocervical columnar cells was proven to correlate with a high percentage of false-negative diagnoses. Intraobserver agreement on the presence or absence of endocervical columnar cells was 85.7% between the two screenings. A predictive value of 57.7% was found for a negative scoring (absence of these cells) while the predictive value of a positive scoring (presence of endocervical cells) was 87.3%. Of the observer scorings, 83.9% concurred with the final diagnosis; there was no significant correlation between that concurrence and the number of years of experience in cytopathology of the observer. For squamous and squamous metaplastic cells in the cervical smear the predictive value of a negative scoring (absence) was only 20.6%. Compared to the final diagnosis, 69.5% of these scorings matched. A significant and relatively high correlation with the experience of the observer was found for the scoring for the presence of metaplastic cells. Even though the predictive values of these quality scorings were relatively low a significantly higher risk for false diagnoses was established when negative scorings were given. It is therefore advisable to have smears with negative scorings for endocervical columnar cells and squamous metaplastic cells always rescreened by another observer.     

Association of human papillomavirus and Chlamydia infections with incidence cervical neoplasia

Incidence cervical neoplasia is defined as disease that becomes manifest during a given period of observation. Association with preceding genital infections having characteristic cytologic findings would seem to be more likely for incidence than for prevalence cases since the usual long latency period of carcinoma in situ (CIS) could allow resolution of infectious processes. For this reason, it was elected to examine the preceding Papanicolaou smears from patients with tissue-confirmed incidence CIS or invasive epidermoid carcinoma. There were 67 women with biopsy-proven CIS or invasive carcinoma of the uterine cervix identified in the files of the University of New Mexico Cytopathology Laboratory from 1966 to 1982 who had two initial negative smears as well as smears at intervals of three years or less. All cytologic smears prior to tissue diagnosis were rescreened for confirmation of cytologic atypia or its absence as well as for morphologic evidence of human papillomavirus (HPV) or chlamydial infections. Control cases matched for age, gravidity, ethnicity and number of smears were reviewed in an identical manner. Koilocytes indicative of HPV infection were found in 17 index cases (25%) and 5 controls (7%) (p = 0.005). Chlamydial infections were identified in 18 index cases (27%) and in 4 controls (6%) (p = 0.001). The times required for conversion from smear negativity to malignancy were determined for each incidence case. The results showed great variability but suggest that the progression to malignancy is not hastened in women with antecedent HPV or chlamydial infections. Our results indicate that the presence of koilocytes and/or chlamydial inclusions in cervical smears serves to identify a group of women with a significantly increased risk of developing cervical carcinoma, even in the absence of concurrent dysplasia.     

Review of cytologic slides from the national women's hospital, New Zealand, cohort of women with cervical intraepithelial neoplasia 3 diagnosed in 1955-1976

OBJECTIVE: To review cytologic slides, mostly at least 25 years old, from women attending National Women's Hospital, Auckland, who had been diagnosed histologically with cervical carcinoma in situ in 1955-1976. STUDY DESIGN: Smears comprised all those from the 2 years following diagnosis as well as all subsequent smears for women who developed "microinvasive" or invasive lower genital tract cancer. The Victorian Cytology Service performed the review using the Australian Modified Bethesda System. was 0.97. RESULTS: Nine percent of 4,930 retrieved slides were technically unsatisfactory. Original (Papanicolaou) and review coding were available for 4,477 slides. Using categories of equivalence, smears coded as normal (original, 59.2%; review, 61.4%) or showing possible or definite high grade abnormalities (original, 25.9%; review, 29.6%) were found in similar proportions. The kappa statistic (0.79) indicated a high level of agreement between original and review coding. In comparison with the review, the sensitivity of the original coding in detecting high grade abnormalities was 0.80, while the ability of the original assessment to categorize smears as not high grade (specificity) CONCLUSION: This comprehensive review found nearly all archived cytology slides to be technically satisfactory and the broad diagnostic cytologic categories from earlier periods (apart from benign lesions) to be concordant with those currently used.     

The significance of endocervical cells in the diagnosis of cervical epithelial changes

A study was made of the relationship of endocervical columnar cells to the cytologic identification of abnormality in the cervix. From a population of women participating in a cervical cancer screening program, a group of women was selected whose smears theoretically should have contained endocervical columnar cells. Endocervical cells were present in 93.1% of the smears and absent in 6.9%. A significantly higher number of moderately and severely atypical epithelial changes was found in smears with endocervical cells as compared with smears without endocervical cells.     

Efficacy of the cytobrush versus the cotton swab in the collection of endocervical cells

Cervical smears should contain endocervical cells to be accepted as adequate for a cytologic diagnosis. Before this study was undertaken, one-third of the smears received in the Cytology Laboratory of Odense University Hospital were inadequate. In an attempt to increase the rate of adequate smears, a randomized study was undertaken to compare the efficacy of the combined spatula-Cytobrush method to that of the spatula-cotton swab method traditionally used by doctors in Denmark. The incidence of smears containing cylindrical and/or metaplastic cells was 89% by the spatula-Cytobrush method as compared to 62% by the spatula-cotton swab method (P less than .001). There were large differences between the rates of adequate smears from the various doctors when using the spatula-cotton swab method (range, 14% to 82%); these differences were far less when using the spatula-Cytobrush method (range, 75% to 100%). A large-scale application of the spatula-Cytobrush method should result in fewer repeat smears required and fewer false-negative smears.     

Cervical cancers diagnosed after negative results on cervical cytology: perspective in the 1980s.

OBJECTIVES--To assess the magnitude of the problem of interval cancers of the cervix (those that are diagnosed within a short time after negative screening test results) in the 1980s, to compare the nature of interval cancers in younger women with that in older women, and, by reviewing negative cervical smears, to determine the proportion of interval cancers that might represent the development of malignancy anew compared with the proportion that might be associated with difficulties in sampling or errors in reporting. DESIGN--An audit of the interval cases of cervical cancer that had been diagnosed within 36 months of a smear having been reported as negative by the Victorian Cytology Gynaecological Service among women registered with cervical cancer during 1982-6. SETTING--The Victorian Cytology Gynaecological Service, a free public sector cytology laboratory in Victoria, Australia. SUBJECTS--138 Women, all of whom had had cervical cancer diagnosed during the 36 months after having had a negative cervical smear. Subjects were divided into two age groups: younger women, aged less than 35; older women, aged 35-69. INTERVENTIONS--Negative slides were reviewed for evidence of optimal sampling and for the presence of cellular abnormalities that had been missed at the time of the original reporting. MAIN OUTCOME MEASURES--The number of interval cases of cancer of the cervix registered during 1982-6. The proportion of interval cases occurring in younger women and the proportion occurring in older women. Division of women into three risk categories based on clinical history and screening history that broadly corresponded to the probability that a diagnosis of cervical cancer might be expected during the 36 months after the issuing of a negative smear report. RESULTS--138 Of 1044 (13.2%) women who had been registered with cervical cancer during 1982-6 had had one or more negative smears during the 36 months preceding the diagnosis of cancer. Interval cancers comprised a larger proportion of registrations of cervical cancer in women aged less than 35 years than in women aged 35-69 (21.1% v 11.0%, p less than 0.01). Women with interval cancer who had had at least three negative smears during the 10 years before the diagnosis of cancer were commoner in the younger age group than in the older age group (7.0% v 2.5%, p less than 0.01). When, however, the number of observed cases of squamous cell carcinoma was related to the number of expected cases in the absence of screening, no significant difference was found between the two age groups (6.8% v 4.8%, p greater than 0.10). The rate of diagnosis of interval cancer per 100,000 negative tests was lower among younger women than among older women (10/100,000 v 16/100,000). Review of the negative slides showed that 11.9% were again considered to be negative with an optimal sample having been obtained as evidenced by the presence of endocervical cells or metaplastic cells, or both. CONCLUSIONS--Interval cancers might comprise a larger proportion of all registered cases of cervical cancer among younger women owing to the larger proportion of such cancers being prevented in this age group. Among women with interval cancer review of the negative slides showed that most were accounted for by suboptimal sampling or by errors of reporting.     

Diagnosing endometrial carcinoma with cervical involvement by cervical cytology

OBJECTIVE: To assess the relationship of a cervical cytologic diagnosis based on number, size and degeneration of malignant clusters and necrotic background to cervical involvement of endometrial carcinoma. STUDY DESIGN: Cervical smears of 53 women with endometrial carcinoma were evaluated for cervical involvement. The cytologic diagnosis was compared with actual involvement, and accuracy was calculated. Retrospectively, cytologic features, including number, size and degeneration of malignant clusters and necrotic background, were analyzed in involved and noninvolved cases. RESULTS: Cervical involvement was confirmed in 15 patients (28.3%). The number and size of malignant clusters in the involved cases were significantly larger than those in the noninvolved cases (P < .001 and < .01, respectively). The proportion of degenerated malignant cells and necrotic background in involved cases were significantly higher than those in noninvolved cases (P < .05). Cytologic diagnosis had a sensitivity and specificity of 62.5% and 86.8%, respectively. CONCLUSION: Cervical smears of involved cases revealed a large number and large size of malignant clusters. These findings support cytologic diagnosis based on number, size and degeneration of malignant cells and necrotic background. Cervical cytology is useful to exclude cervical involvement because of its high specificity and can help detect cervical involvement because of its moderately high sensitivity.     

Clinical significance of atypical glandular cells by the 2001 Bethesda System in cytohistologic correlation

OBJECTIVE: To evaluate incidence, cytology findings and pathology outcome of atypical glandular cells (AGC) in Pap smears according to the 2001 Bethesda criteria. STUDY DESIGN: From 103,073 consecutive Pap smears, 113 (0.1%) AGC cases were identified. Of these, 91 (80%) had adequate histologic evaluation included in this study. RESULTS: Abnormal histology findings were seen in 38 patients (42%). Final pathology results revealed 14 endometrial adenocarcinomas, 5 endocervical adenocarcinomas, 1 cervical squamous cell carcinoma, 1 endometrial stromal sarcoma, 6 other malignancies, 4 endocervical adenocarcinomas in situ, 4 cases ofendometrial complex byperplasia, 1 case of endocervical glandular dysplasia and 2 cases of cervical intraepithelial neoplasia 3 with glandular involvement. Women with AGC, favor neoplasia, were more likely to have significant pathology than those with AGC, not otherwise specified, 74% vs. 33% (p = 0.002). Some characteristic background cytologic findings were also noticed in most cases of endometrial, fallopian tube and endocervical adenocarcinoma. CONCLUSION: A diagnosis of AGC is more clinically significant by the 2001 Bethesda System, especially the "AGC, favor neoplastic" category. Some background cytologic features are important because they are indicators of malignancy.     

Histiocytes and the detection of endometrial adenocarcinoma

Histiocytes have long been recognized as part of the milieu of endometrial carcinoma in gynecologic smears. In an effort to determine whether a quantitative assessment of histiocytes, especially in the absence of endometrial cells, could increase the effectiveness of the cervicovaginal smear for diagnosis of endometrial carcinoma, smears obtained prior to a tissue diagnosis of endometrial adenocarcinoma were evaluated from 44 postmenopausal women. Smears from 97 age-matched patients in the same clinic were also evaluated and used as a control group for the endometrial carcinoma patients. All smears were evaluated for the presence of histiocytes and for the presence of benign or malignant endometrial cells, with the histiocytes quantitated as minimal (less than 5 per high-power field [HPF]), moderate (5 to 10/HPF) or heavy (greater than 10/HPF). Sensitivity and specificity were calculated to assess the role of histiocytes in the presence and in the absence of endometrial cells using cytologic findings. Our data indicate that the presence of moderate or heavy numbers of histiocytes on cervicovaginal smears of postmenopausal women increased the cytologic sensitivity from 61% to 82% when considered a marker of disease along with endometrial cells. These results suggest that attention to the presence of histiocytes on cervicovaginal smears may increase the utility of cytology for the diagnosis of endometrial lesions and may be a useful guideline for the cancer-related gynecologic examination.     

Cellular composition of cervical smears in relation to the day of the menstrual cycle and the method of contraception

The influence of the day of the menstrual cycle and the method of contraception on the cellular composition of cervical smears was investigated. The percentage of unsatisfactory smears during the first four days of the cycle was understandably very high, leaving only 80% of the smears of sufficient quality for cytologic diagnosis. The percentage of smears of insufficient quality during the remainder of the cycle was significantly higher in women using oral hormonal contraceptives. The percentages of smears containing endocervical columnar cells, a criterion for judging smears to be of high quality, differed significantly among women using different modes of contraception. The highest percentage of smears without endocervical columnar cells was found in women using oral contraceptives; during the first half of the cycle in these women, smears were of higher quality than during the second half of the cycle. In women not practicing contraception or using nonhormonal methods of contraception, the differences in cellular composition during the cycle, though significant, were too small to be of practical importance. Women using oral contraceptives thus have an increased risk for a potential false-negative diagnosis because of the higher percentage of smears of unreliable quality taken in these women. In women using oral hormonal contraceptives, smears should be taken during the first half of the cycle because of the higher percentage of smears of high quality in that period.     

Diagnostic accuracy of squamous cervical lesions studied in spatula-cytobrush smears

The cytologically positive cases found in 25,300 cervical smears of spatula samples and 6,168 smears prepared by combined spatula-Cytobrush sampling were analyzed. The diagnostic accuracy (the correlation between the cytologic and histologic diagnoses) was the same for both types of sampling. As to the histologic diagnosis, the rates of severe dysplasia, carcinoma in situ and squamous carcinoma in the spatula-Cytobrush group were more than twice as high as in the spatula group. In the spatula group, the majority of abnormal cells was of the mature type. In the spatula-Cytobrush group, the majority of smears contained a mixture of immature and mature abnormal cells. The more immature lesions, which are often located higher in the endocervical canal, seem to be better sampled by the Cytobrush. The results indicate that the Cytobrush reaches areas that a spatula cannot reach, resulting in a higher diagnostic efficiency.     

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.     

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.     

Cost effectiveness of population screening and rescreening for cervical cancer in the Netherlands

In a screening program for cervical cancer held in the western part of the Netherlands in 1978, it was shown that the incidence of positive cases dropped from 8.0% to 1.4% when repeat screening was performed within two years; however, the incidence of mild dysplasia remained the same (13.0%). Forty percent of the allocated funds were used for canvassing. Recanvassing of the no-response group did not result in the finding of positive cases. Of the ten positive cases in the rescreened group, four had had inadequate negative smears previously, and two had had adequate negative smears; in two cases the previous smears were reclassified as dysplasias, and in the two remaining cases endocervical carcinoma cells were found in the additional endocervical smear. In light of the high canvassing costs of population screening and the low detection rate of positive cases in the rescreened group, as described in this paper, it appears overly costly to repeat population screening with two years.     

Review of cervical smears from 76 women with invasive cervical cancer: cytological findings and medicolegal implications

OBJECTIVE: To review cervical smears from 76 women which were taken prior to the diagnosis of invasive cervical cancer and to determine the appropriateness of the cytology reports issued on the smears. METHODS: Cervical smears, clinical records, cervical smear history and cytology reports from 76 women with invasive cervical cancer were reviewed. After microscopic review of the cervical smears, the cases were divided into two groups: Group 1 comprised 50 women who were found to have had at least one false-negative (F/N) smear report prior to the diagnosis of invasive cervical cancer. Group 2 comprised 26 women for whom no evidence of F/N reporting was found. RESULTS: A total of 209 cervical smears from the 50 women in group 1 were available for review (range 2-12 smears per woman); 100 of the 209 smears were considered to have been reported appropriately. Ninety-seven smears which had been reported originally as negative or inadequate were found, on review, to contain numerous severely dyskaryotic cells and were reclassified as F/N smears. All of the 50 women had at least one F/N smear and 29 had two or more. Twelve smears from eight women contained only a few (<200 severely dyskaryotic cells). Forty women developed invasive squamous carcinoma and 10 developed invasive adenocarcinoma. The stage at diagnosis ranged from 1A to stage 4. Seventy-one smears from the 24 women in group 2 were available for review (range 1-15 smears per woman). In two cases included in group 2, no smears were provided for review as the smears had been lost or mislaid. Review of the 71 smears confirmed the accuracy of the original cytological classification of the smear. Nineteen women were diagnosed with squamous cancer, two microinvasive cancer, one glassy cell, two adenocarcinomas, and one with adenosquamous carcinoma. One women was found to have an embryonal rhabdomyosarcoma of the corpus uteri involving the cervix. DISCUSSION/CONCLUSION: The medicolegal implications are discussed in the light of the above findings. Evidence of breach of duty of care was presented in all 50 cases in group I although causation was not established in every case. There was no evidence of failure of duty of care in terms of the standard of the cervical cytology reports issued or standard of clinical management in 17 of the 26 cases in group 2. However, in seven of the 26 cases in group 2, clinical management of the case was substandard due to failure to investigate symptoms of irregular bleeding regardless of a negative cytology report (two cases), failure to act upon a suspicious smear report or consecutive inadequate smear reports (two cases), failure of follow-up after treatment of CIN3 (two cases) and histological misdiagnosis (one case).     

Cervicovaginal cytology in uterine adenocarcinoma and adenosquamous carcinoma. Comparison of cytologic and histologic findings

To investigate the diagnostic accuracy and to characterize the findings in false-negative cases, the results of cervicovaginal cytology in 56 adenocarcinomas and 25 adenosquamous carcinomas (42 cervical, 36 endometrial, 2 metastatic and 1 arising synchronously from both cervix and endometrium) were reviewed, including review of the actual slides in 56 cases. Overall, 80% of the initial cytologic diagnoses resulted in diagnostic curettage (i.e., cytology was effectively positive); 84% of the postreview diagnosis were effectively positive. Nine cytology slides showed no malignant cells; eight of these negative smears showed repair, five were atrophic, two showed a high estrogen effect and one had enlarged atypical bare nuclei. These false-negative diagnoses were associated with an endometrial primary site (P less than .01), endometrioid histology (P less than .005), low-grade or intermediate-grade histology (P less than .005), small size of tumor (P less than .05) and absence of cervical involvement (P less than .005) in those cases in which a hysterectomy was performed. False-negative diagnoses were not associated with an absence of endocervical cells or with scanty cellularity. Of 39 cervical and 28 endometrial carcinomas with a positive cytologic diagnosis (initially or after review of the available slides), cytology correctly identified the primary site in 18% and 54% of the cases, respectively. Cytology incorrectly classified the anatomic site of four cervical and three endometrial carcinomas and considered one case arising in both the endometrium and cervix to be endometrial. Routine cervicovaginal cytology does have a role in screening for uterine glandular carcinoma; to maximize its diagnostic sensitivity, we suggest using a recommendation for curettage in the report of positive cases so that all of the varied cytologic diagnoses associated with glandular carcinomas will receive a uniform clinical response. In those cases with preserved cancer cells, a correlation can be made with the histologic type of the carcinoma, rather than with the anatomic site.     

Screening errors in cervical cytologic screening

A total of 555 cervical smears, originally classified as Papanicolaou classes I and II, from women in whom three years later cytologic findings consistent with moderate dysplasia, severe dysplasia, carcinoma in situ and invasive cancer were diagnosed were reviewed in order to estimate the screening error. The initial diagnosis proved to be underestimated in 17.5% of the smears. The two diagnoses correlated in 70.2% of the smears while 12.3% of the smears that contained no abnormality were judged to be inadequate for making a diagnosis, probably representing sampling errors. Quality-control measures to reduce these errors are briefly summarized.