A case-control study of true-positive versus false-negative cervical smears in women with cervical intraepithelial neoplasia (CIN) III

False Negative Results in Cervical Cancer Screening-Risks, Reasons and Implications for Clinical Practice and Public Health

False negative (FN) results in cervical cancer (CC) screening pose serious risks to women. We present a comprehensive literature review on the risks and reasons of obtaining the FN results of primary CC screening tests and triage methods and discuss their clinical and public health impact and implications. Misinterpretation or true lack of abnormalities on a slide are the reasons of FN results in cytology and p16/Ki-67 dual-staining. For high-risk human papillomavirus (HPV) molecular tests, those include: truly non-HPV-associated tumors, lesions driven by low-risk HPV types, and clearance of HPV genetic material before sampling. Imprecise disease threshold definition lead to FN results in visual inspection with acetic acid. Lesions with a discrete colposcopic appearance are a source of FN in colposcopic procedures. For FAM19A4 and hsa-miR124-2 genes methylation, those may originate from borderline methylation levels. Histological misinterpretation, sampling, and laboratory errors also play a role in all types of CC screening, as well as reproducibility issue, especially in methods based on human-eye evaluation. Primary HPV-based screening combined with high quality-assured immunocytochemical and molecular triage methods seem to be an optimal approach. Colposcopy with histological evaluation remains the gold standard for diagnosis but requires quality protocols and assurance measures.

Adequacy in Endocervical Curettage

OBJECTIVES

Specimen adequacy is an important quality assurance component of a cervical Papanicolaou test. Although consensus exists on minimal acceptable cellularity for cervical Papanicolaou tests, no such criteria exist for endocervical curettage (ECC) specimens. We sought to identify minimum acceptable cellularity for accurate diagnosis of high-grade dysplasia (HGD) on ECC.

METHODS

All patients with HGD diagnosed in a loop electrosurgical excision procedure (LEEP) from May 8, 2018, to December 18, 2019, and an ECC in the preceding 6 months at our institution were included (n = 51). All ECCs performed before the LEEP were evaluated for cellularity of squamous cells using Aperio eSlide Manager (Leica Biosystems). Biopsy results concurrent with the ECC were noted. We compared the number of squamous cells in positive and negative ECC specimens using a t-test. The proportion of ECC specimens and concurrent biopsies undergoing immunohistochemical (IHC) staining for p16 were compared using the χ2 test. P < .05 was considered significant.

RESULTS

Endocervical curettage specimens positive for HGD have increased cellularity compared with negative ECC specimens (mean cellularity, 10,165 vs 1,055; P < .05). Further, IHC staining for p16 was more likely to be performed on an ECC specimen positive for HGD than on a negative ECC specimen (50% vs 3%; P < .05). Biopsies performed concurrently with a negative ECC finding were more likely to undergo p16 IHC than biopsies performed concurrently with a positive ECC finding (51% vs 7%; P < .05). Finally, we observed no difference in the proportion of biopsies undergoing IHC staining for p16 when comparing biopsies positive for HGD with negative biopsies (37% vs 46%; P = .33).

CONCLUSIONS

We find cellularity of approximately 10,000 cells adequate to diagnose HGD in an ECC specimen and cellularity of approximately 1,000 cells to be inadequate. Further, we find p16 IHC commonly used as a "rule-in" test on ECC specimens at our institution. Biopsies accompanying an ECC specimen negative for HGD are more likely to undergo p16 IHC than those accompanying an ECC specimen positive for HGD, but there is no difference in the proportion of biopsies undergoing p16 IHC when comparing positive and negative results in the biopsies themselves. These findings further support the need for adequate cellularity for diagnosis in ECC, especially when a biopsy is technically difficult. Further areas for exploration include investigating laboratory procedures to maximize the cellularity of ECC specimens.

Self-collected Papanicolaou tests in the United States market: more questions than answers

The United States Food and Drug Administration held a public hearing in January 2018 to consider how it should evaluate a self-collection device for cervical cytology. Although no such device has been approved for use in the US market, the implications for patients and cytologists could be both sweeping and complex. Herein, the existing literature basis for self-collected Papanicolaou testing is reviewed, and some questions raised by this testing are considered. Questions include: what would be the value to patients; how effective could self-collected Papanicolaou tests be; how might ordering and collection work; what are the unique pre-analytic, analytic, and post-analytic challenges of self-collected Papanicolaou testing; and what effect might self-collection have on cervical cancer rates?

The value of a transformation zone component in anal cytology to detect HSIL

BACKGROUND

In a cytology-based screening program intended to prevent anal cancer, the anal transformation zone (TZ) should be adequately sampled because it is the site most susceptible to the development of the cancer precursor, high-grade squamous intraepithelial lesion (HSIL). An adequate TZ component is defined as comprising at least 10 rectal columnar or squamous metaplastic cells. In the current study, the authors examined whether the presence of a TZ component in anal cytology correlated with the detection of histological HSIL.

METHODS

In a natural history study of anal human papillomavirus infection in homosexual men, all participants underwent liquid-based cytology and high-resolution anoscopy (HRA) with or without biopsy at each visit. True-negative cytology (negative cytology with non-HSIL biopsy or negative HRA), false-negative cytology (negative cytology with HSIL biopsy), and true-positive cytology (abnormal cytology with HSIL biopsy) were compared with regard to the presence or absence of a TZ component.

RESULTS

Of 617 participants, baseline results included 155 true-positive results, 191 true-negative results, and 31 false-negative results. The absence of an adequate TZ component was found to be significantly higher for false-negative (32.3%) than for either true-positive (11.0%; P = .0034) or true-negative (13.1%; P = .0089) results.

CONCLUSIONS

Significantly more false-negative cases lacked a TZ component compared with either true-positive or true-negative cases. TZ cells may be an important indicator of sample quality for anal cytology because, unlike cervical sampling, the anal canal is not visualized during cytology sampling. Cancer Cytopathol 2016;124:596-601. © 2016 American Cancer Society.

HPV16 RNA patterns defined by novel high-throughput RT-qPCR as triage marker in HPV-based cervical cancer precursor screening

OBJECTIVE

Cervical cancer precursor screening by HPV testing has a low positive predictive value for advanced lesion. HPV16 RNA patterns characteristic for HPV16-transformed cells but based on laborious, cost-intensive singleplex NASBA reactions promised high value in triaging HPV16 DNA-positive women.

METHODS

We developed two high-throughput reverse transcriptase quantitative (RT-q) PCR assays for the HPV16 transcripts E6*I, E1^E4 and E1C and the cellular transcript ubiquitin C and analysed RNA of 158 singly HPV16 DNA-positive cervical cell samples archived in PreservCyt buffer for the presence of transformation-associated HPV16 RNA patterns, i.e., upregulation of E6*I relative to E1^E4 and/or presence of E1C.

RESULTS

HPV16 RNA pattern analyses classified 85% of 58 samples diagnosed ≤CIN1 (no cytologically and histologically detectable cervical lesion or CIN grade 1) as negative and 90% of 59 samples diagnosed as ≥CIN3 (CIN grade 3 or invasive cancer) as positive. Among 41 CIN grade 2 samples representing an intermediate lesion group, 49% were HPV16 RNA patterns-positive. Interestingly, 3 of 4 HPV16 RNA patterns-positive lesions initially diagnosed as ≤CIN1 at follow-up 5-24 months later had progressed to ≥CIN2.

CONCLUSIONS

We successfully developed and validated a second generation of HPV16 RNA patterns assay by rapid RT-qPCR as triage marker for HPV16 DNA-positive women offering clinical utility to distinguish between the need for immediate colposcopy and continued observation. Limited follow-up data suggests that HPV16 RNA patterns-positivity in ≤CIN1 lesions can predict disease progression.

Internal quality control for cervical cytopathology: comparison of potential false-negatives detected at rapid prescreening and at 100% rapid review

OBJECTIVE

To evaluate the performance of rapid prescreening (RPS) and 100% rapid review (RR-100%) as internal quality control (IQC) methods assessed by outcome at colposcopy, histopathology and repeat cytopathology for cases with false-negative results on cervical cytopathology at routine screening (RS).

STUDY DESIGN

Out of 12,208 cytology smears analyzed, 900 were abnormal. Of these, 656 were identified at RS, and 244 were false-negative, with 90.2% identified at RPS and 57.4% at RR-100%. Of the 900 abnormal cases, 436 were submitted for additional testing.

RESULTS

Of the 244 women with cytopathological abnormalities identified only by the IQC methods, 114 had supplementary examinations: 35 were submitted for colposcopy, 22 for biopsy and 99 for repeat cytopathology. The sensitivity of RPS for the detection of abnormalities identified on colposcopy, histopathology and repeat cytopathology was 87.5% (95% CI 67.6-97.3), 82.4% (95% CI 56.6-96.2) and 95.7% (95% CI 85.2-99.5), respectively. The sensitivity of RR-100% was 54.2% (95% CI 32.8-74.4), 52.9% (95% CI 27.8-77.0) and 47.8% (95% CI 32.9-63.1), respectively. RPS was more sensitive than RR-100% when compared to the findings on colposcopy (p = 0.011) and repeat cytopathology (p = 0.000). When compared to colposcopy, histopathology and repeat cytopathology, the sensitivity of RS was 83.2% (95% CI 76.1-88.9), 85.7% (95% CI 78.1-91.5) and 73.3% (95% CI 66.0-79.7), respectively.

CONCLUSION

RPS performed better than RR-100% when compared to the results of colposcopy and repeat cytopathology.

Direct human papillomavirus E6 whole-cell enzyme-linked immunosorbent assay for objective measurement of E6 oncoproteins in cytology samples

A novel, whole-cell enzyme-linked immunosorbent assay (ELISA) based on a non-type-specific anti-human papillomavirus (HPV) E6 antibody was tested on 182 residual cytological specimens. For samples with a designation of more severe than cervical intraepithelial neoplasia grade 3 (CIN3+), 83% tested positive for E6; in a subset with paired testing for E6 ELISA and HPV DNA, 72% tested E6 positive and 92% tested high-risk (HR)-HPV DNA positive (P = 0.2). Among the women with a less than CIN3 diagnosis, 31% and 47% tested positive for E6 and HR-HPV DNA, respectively (P = 0.0006).

Prevalence of abnormalities influences cytologists' error rates in screening for cervical cancer

CONTEXT

Medical screening tasks are often difficult, visual searches with low target prevalence (low rates of disease). Under laboratory conditions, when targets are rare, nonexpert searchers show decreases in false-positive results and increases in false-negative results compared with results when targets are common. This prevalence effect is not due to vigilance failures or target unfamiliarity.

OBJECTIVE

To determine whether prevalence effects could be a source of elevated false-negative errors in medical experts.

DESIGN

We studied 2 groups of cytologists involved in cervical cancer screening (Boston, Massachusetts, and South Wales, UK). Cytologists evaluated photomicrographs of cells at low (2% or 5%) or higher (50%) rates of abnormality prevalence. Two versions of the experiment were performed. The Boston, Massachusetts, group made decisions of normal or abnormal findings using a 4-point rating scale. Additionally, the group from South Wales localized apparent abnormalities.

RESULTS

In both groups, there is evidence for prevalence effects. False-negative errors were 17% (higher prevalence), rising to 30% (low prevalence) in the Boston, Massachusetts, group. The error rate was 27% (higher prevalence), rising to 42% (low prevalence) in the South Wales group. (Comparisons between the 2 groups are not meaningful because the stimulus sets were different.)

CONCLUSIONS

These results provide the first evidence, to our knowledge, that experts are not immune to the effects of prevalence even with stimuli from their domain of expertise. Prevalence is a factor to consider in screening for disease by human observers and has significant implications for cytology-based cervical cancer screening in the post-human papillomavirus vaccine era, when prevalence rates of high-grade lesions in the population are expected to decline.

Clinicopathologic features associated with cytohistologic noncorrelation in the diagnosis of cervical dysplasia: a study of concurrently obtained samples

On the basis of the unique subset of our database comprising patients who received a Papanicolaou test and a cervical biopsy during the same clinic visit, clinicopathologic factors potentially associated with cytohistologic diagnostic noncorrelation in these concurrently collected samples is investigated. In the first analysis, a selected group of variables potentially associated with noncorrelation relative to the diagnosis of high-grade dysplasia were examined, whereas the second analysis was centered on the effect of varying levels of Papanicolaou test inflammation (below the Bethesda 2001 threshold, ie, partially obscuring inflammation) on noncorrelation regarding the overall diagnosis of dysplasia. For the latter, the overall density of neutrophilic infiltrate on each Papanicolaou test slide was graded in a blinded fashion on a 4-tiered scale (no significant amount, mild, moderate, and severe), followed by a comparison of correlating and noncorrelating cases at each tier. There was no overrepresentation of noncorrelating cases in severe inflammation group. Indeed, correlating and noncorrelating cases did not significantly differ at any level of inflammation. In the first analysis, correlating (n = 17) and noncorrelating (n = 17) cases did not significantly differ in patient age, number of biopsies obtained, endocervical curettage status, glandular involvement by high-grade dysplasia, or frequency of background grade 1 cervical intraepithelial neoplasia. Noncorrelating cases were more likely than correlating cases to be grade 2 cervical intraepithelial neoplasia rather than grade 3 or worse (82% vs 41%, respectively, P = .02), which is probably attributable to the absence of a basaloid proliferation in the most superficial layers of grade 2 lesions. Furthermore, noncorrelating cases showed a comparatively smaller percentage of submitted biopsies involved by high-grade dysplasia (52% vs 75%, respectively, P = .03), consistent with smaller extent of disease. These findings further illustrate that lesional factors are important potential contributors to the false-negative rate of the Papanicolaou test.

European guidelines for quality assurance in cervical cancer screening: recommendations for cytology laboratories

The quality of a cervical cytology laboratory depends on adequate handling and staining of the samples, screening and interpretation of the slides and reporting of the results. These guidelines give an overview of procedures recommended in Europe to manage the balance between best patient care possible, laboratory quality assurance and cost effectiveness and will be published as a chapter 4 in the European Guidelines for Quality Assurance in Cervical Cancer Screening. The laboratory guidelines include protocols for personnel and organisation, material requirements, handling and analysing cervical samples, recording of results, quality management and communication. The section on quality management is comprehensive and includes protocols for all aspects of internal and external quality assurance. The guidelines are extensively referenced and as far as possible the recommendations are evidence-based.

Significance and possible causes of false-negative results of reflex human papillomavirus infection testing

BACKGROUND

The objective of this study was to assess the rate and possible reasons for false-negative (FN) reflex human papillomavirus (HPV)-DNA tests.

METHODS

The authors reviewed all ThinPrep cervical specimens that were submitted for reflex HPV-DNA testing using the Digene Hybrid Capture II (HC2) method from January 2002 to January 2004. Follow-up biopsies were reviewed. The results were considered HPV-FN if the HPV-DNA test was negative and the biopsy was positive for grade > or =2 cervical intraepithelial neoplasia (CIN2+), and the results were considered true positive (HPV-TP) if the HPV-DNA test was positive and the biopsy showed CIN2+. HPV-FN cases were compared with HPV-TP cases regarding the grade and extent of CIN, the number of abnormal cells on the original ThinPrep slide, and the presence of amplifiable, viral DNA on biopsy.

RESULTS

In total, 1520 (66%) of 2309 patients who had diagnoses of atypical squamous cells of undetermined significance (ASCUS) were negative for HPV DNA and 789 patients of 2309 patients (34%) were positive for HPV DNA. Three hundred sixteen women (40%) who had a positive HPV-DNA test underwent a biopsy. Of those, 36 biopsies (11%) showed CIN2+ (HPV-TP), and 154 biopsies (66%) showed CIN1. Cervical tissue was available for review from 82 women who had negative HPV-DNA tests; of these, 6 tissue samples (7%) showed CIN2+ (HPV-FN), and 13 tissue samples (16%) showed CIN1. Therefore, in the total ASCUS population that was triaged with reflex HPV testing, there were at least 42 women who were diagnosed with CIN2+, for an estimated CIN2+ FN fraction of 14% (6 of 42 women). HPV-FN lesions were smaller (but the difference was not statistically significant) and shed significantly fewer abnormal cells than HPV-TP cases. Polymerase chain reaction testing for viral DNA in the biopsy was detected in 3 of 6 women who had HPV-FN results; none of those positive results demonstrated a viral type that was not included in the Digene probes.

CONCLUSIONS

Although the rate of FN high-grade lesions was significantly higher than that reported in the ASCUS/Low-grade Squamous Intraepithelial Lesion Triage trial, most missed lesions were small and shed few abnormal cells. It was assumed that those lesions were either in early stages or in regressing stages, which made their clinical significance uncertain.

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).

Influence of specimen adequacy on the diagnosis of ASCUS

The impact of specimen adequacy on the diagnosis of cervical cytology is not fully understood. Virtually, the greatest impact of smear quality limitation factors is on the diagnosis of atypical squamous cells of undetermined significance (ASCUS) because this category is more susceptible to interpretation mistake due to its criteria subjectivity. This study aims to evaluate the impact of smear quality impairing factors on the diagnosis of ASCUS. The 1,507 cases of ASCUS studied were obtained from the Cervical Cancer Screening Program of Paraná (CCSPP). The cases were reviewed by expert cytopathologists and the results were correlated to the specimen adequacy. The results showed that the presence of obscuring blood impairs the correct diagnosis and leads the pathologist to overdiagnose negative smears as ASCUS. The presence of adequate endocervical sampling contributes to a higher rate of correct ASCUS diagnoses but did not influence the pathologist to over- or underestimate the cytological findings.

The Bethesda System 2001: an update of new terminology for gynecologic cytology

From the inception of TBS in 1988, it has been well received by the pathology and clinical communities. The need for a unifying system of nomenclature was so great that most of the laboratories in the United States, as well as in numerous countries worldwide, quickly adopted TBS. By 1991, only 2 years after the initial publication of the initial TBS, 57% of United States laboratories were using the system. By 1994, almost 90% of laboratories were using TBS [28]. Although explanations for such a quick acceptance of TBS are many, one of the leading reasons is, most certainly, the sound and thoughtful basis for all of the elements of TBS. These include: (1) nomenclature that provides uniform diagnostic terminology to facilitate unambiguous communication between the laboratory and the clinician; (2) diagnostic categories that incorporate the latest scientific information on the pathogenesis and prognosis of cervical lesions; and (3) incorporation of the evaluation of specimen adequacy as an integral part of the report. From the beginning, TBS was more than just a diagnostic lexicon. When Drs. Kurman and Solomon decided that something had to be done about the diagnostic mess in GYN cytology, they did not develop another system. Instead, they convened an international consensus conference to look at the problem and come up with a comprehensive, relevant solution. The input from the entire community, which lent strength to the initial TBS, has continued to the present. This is highlighted by the enormous amount of input that was received by the 2001 TBS forum groups that enabled them to fine tune the existing terminology to meet the needs of today's clinicians. The result, continues to be an evolving, comprehensive, and clinically relevant entity, that should meet the needs of pathologists and clinicians for the foreseeable future.

ASCCP patient management guidelines: Pap test specimen adequacy and quality indicators

Our objective was to provide management guidelines according to Papanicolaou (Pap) test specimen adequacy based on literature review and expert opinion. A task force named by the American Society for Colposcopy and Cervical Pathology (ASCCP) conducted a literature review and discussed appropriate management. The Steering Committee of the ASCCP and other experts reviewed the guidelines. The guidelines recommend a repeated Pap test in 12 months for most women undergoing routine annual/biennial screening if the current Pap test is negative but either lacks an endocervical/ transformation zone component or is partially obscured. Indications for considering an earlier repeat are also provided. The preferred managementfor unsatisfactory Pap tests is a repeated Pap test within a short interval of 2 to 4 months. The management guidelines will help promote optimal and uniform follow-up of women according to Pap test specimen adequacy.

ASCCP Patient Management Guidelines: Pap Test Specimen Adequacy and Quality Indicators

OBJECTIVES

To provide management guidelines according to Pap test specimen adequacy based on literature review and expert opinion.

METHODS

A task force named by the American Society for Colposcopy and Cervical Pathology conducted a literature review and discussed appropriate management. The steering committee of the American Society for Colposcopy and Cervical Pathology and other experts reviewed the guidelines.

RESULTS

The guidelines recommend a repeat Pap test in 12 months for most women who are undergoing routine annual/biennial screening if the current Pap test is negative but either lacks an endocervical/transformation zone component or is partially obscured. Indications for considering an earlier repeat are also provided. The preferred management for unsatisfactory Pap tests is a repeat Pap test within a short interval of 2 to 4 months.

CONCLUSIONS

The management guidelines will help promote optimal and uniform follow-up of women's Pap tests, according to Pap test specimen adequacy.

Endocervical component: is it a determinant of specimen adequacy?

There is controversy in the literature concerning the presence or absence of an endocervical component as a determinant of the adequacy of cervical cellular samples. The purpose of this retrospective 2-yr study (January 1, 1999-December 31, 2000) was to evaluate the diagnostic accuracy of ThinPrep Pap Tests with the presence or absence of an endocervical component from 151 women with subsequent tissue-verified cervical intraepithelial neoplasia (CIN) II/III. Of the 138 Pap Tests containing an endocervical component, 100 (73%) showed exact cyto/histologic correlation and 38 (27%) were discordant. Of the 13 Pap Tests lacking an endocervical component, 10 (77%) showed exact correlation and 3 (23%) were discordant. Statistical analysis showed no significant difference in the detection of a high-grade squamous intraepithelial lesion (HSIL) in those ThinPreps that contained an endocervical component from those that did not (P > 0.5). Further analysis of the 41 discordant ThinPrep Pap Tests showed no significant difference between negative Pap Tests and discordant, yet abnormal Pap Tests (atypical squamous cells of undetermined significance, or low-grade squamous intraepithelial lesions) and the presence or absence of an endocervical component (P = 0.25). The results of this study seem to indicate that the issue of the lack of an endocervical component as a determinant of cervical specimen adequacy should be revisited.

Clinical perception of disease probability associated with Bethesda System diagnoses

The degree to which clinical perceptions of Papanicolaou smear sensitivity contribute to patient mismanagement is uncertain. A voluntary, anonymous questionnaire was mailed to 350 obstetricians/gynecologists (OGYNs) and 350 other primary care providers (PCPs) located in Pennsylvania or Ohio. The clinicians estimated the probability of no disease, dysplasia, and invasive carcinoma for 1 of 7 Bethesda System diagnoses. Differences in probability estimates between provider types and between the clinicians and medical literature data were measured. The response rate was 22.7%. Compared with published values, clinicians estimated similar disease probabilities for many diagnoses. However, for some diagnoses, the probability estimates differed considerably from published values (e.g., overestimation of dysplasia and invasive carcinoma for benign diagnoses and underestimation of dysplasia for some dysplasia diagnoses), and such errors could contribute to patient mismanagement. OGYNs generally were more accurate in probability estimates than PCPs. Methods to convey more accurately these diagnostic disease probabilities should be examined.

The borderline cervical smear: colposcopic and biopsy outcome

AIMS

To review the outcome of women referred with smears showing borderline nuclear change (BNC), and to determine any differences in outcome if BNC was persistent, preceded by dyskaryosis, or followed treatment for cervical intraepithelial neoplasia (CIN). In addition, to determine criteria that might permit delineation of a BNC subtype, predictive of CIN.

METHODS

The records of 178 women referred for colposcopy in 1993, with last smear showing BNC, were obtained from our laboratory database. The cytology, colposcopy, and biopsy follow up for a five year period were also obtained. The patients were divided into three categories according to their smear status before the last referral borderline smear: category 1, persistent BNC (n = 39); category 2, BNC preceded by dyskaryotic smears (n = 100); and category 3, BNC after treatment for CIN (n = 39). The referral borderline smears were reviewed on cases with negative outcome and those with a biopsy diagnosis of CIN2 and CIN3.

RESULTS

In 50 women (28%) no biopsy was deemed necessary after colposcopic assessment. The biopsy results in the remaining 128 (72%) women were as follows: normal in 18 (10%), koilocytosis in 12 (7%), CIN1 in 45 (25%), CIN2 in 32 (18%), and CIN3 in 21 (12%) women. High grade lesions (CIN2, CIN3) were seen on biopsy in 14 of 39, 33 of 100, and six of 39 cases in category 1, category 2, and category 3, respectively. Blind review of the referral borderline smears from 53 women with a biopsy diagnosis of high grade lesions (32 CIN2, 21 CIN3) confirmed they were borderline in 23, upgraded them to mild dyskaryosis in 15, and found that 14 cases of isolated moderate or severe dyskaryotic cells had been missed originally. The borderline change was in mature squamous cells in five of 23 and in immature metaplastic epithelium in 18 of 23 cases. After smear review in 68 women with negative outcome, 36 smears were reclassified as negative in keeping with inflammation and atrophy, three were considered unsatisfactory, one was upgraded to CIN1, and 28 were confirmed as BNC. Of the latter, 25 of 28 were in mature squamous cells. The five year follow up on women with negative colposcopy (n = 50), negative loop excision of transformation zone (LETZ) (n = 18), and LETZ with koilocytosis (n = 12) showed subsequent high grade CIN on LETZ in 16, 0, and two patients, respectively.

CONCLUSIONS

On referral of women for colposcopy with last smear showing BNC, the outcome was high grade CIN in over 30% of cases, irrespective of whether the borderline smear was preceded by another borderline smear or by a dyskaryotic smear. In contrast, in those referred because of BNC after treatment of CIN, high grade CIN was seen less frequently (15% of cases). Furthermore, in cases that necessitated loop excisions, high grade CIN was seen in 41%. This study also showed that BNC associated with inflammation or atrophy, or BNC in mature squamous cells, appears to have lower predictive value for CIN than those cases where BNC is associated with immature metaplastic epithelium. The use of terms such as "BNC favour reactive" for the former and "BNC favour dyskaryosis" for the latter is recommended, together with follow up by cytology and colposcopy, respectively.