The quality and accuracy of cervical cytology: A study of five sampling devices in a colposcopy clinic

Subtyping borderline nuclear changes: is it of value in predicting high-grade cervical intraepithelial neoplasia on histology?

The aim was to determine the association between the subtypes of borderline nuclear changes (BNC) in cervical smears and high-grade cervical intraepithelial neoplasia (HCIN). BNC was reported in 23236 smears received in our laboratory over a 7-year period, 3278 patients were referred for colposcopy. Analysis was restricted to 2007 cases, which fitted the criteria of: (1). consistent subtyping of borderline change and (2). cervical histology result within 12 months of the last abnormal smear. BNC was reported in six categories and correlated with histology. Atypia bordering on dyskaryosis, atypical metaplastic cells and endocervical atypia, were associated with HCIN in 25%, 25.4% and 23.8% of cases, respectively. Dyskeratosis and koilocytotic atypia were associated with HCIN in 19.2% and 13.7% of cases, respectively. Some subtypes of borderline change are more frequently associated with HCIN. The difference is not sufficient to dictate clinical management.

How predictive is a cervical smear suggesting glandular neoplasia?

The prevalence of endocervical adenocarcinoma and its precursors has increased, in part due to increased diagnostic awareness of these lesions. To date, limited information has been published regarding the predictive value of glandular abnormalities in cervical smears. This study details the histological follow up of 418 cervical smears showing glandular abnormality, reported in our department over a six year period from 1993 to 1998. Histological follow up was available for 395 of the 418 smears (94.50%). The overall positive predictive value (PPV) for this group of smears was 72.66% for either significant glandular or squamous pathology (at least low grade cervical glandular intraepithelial neoplasia or CIN2 on follow up biopsy), and 55.70% for significant glandular pathology alone. Examination of subcategories of abnormal glandular smear showed that the PPV increased with the degree of abnormality reported within the smears.

Accuracy of the Papanicolaou test in screening for and follow-up of cervical cytologic abnormalities: a systematic review

PURPOSE

To evaluate the accuracy of conventional and new methods of Papanicolaou (Pap) testing when used to detect cervical cancer and its precursors.

DATA SOURCES

Systematic search of English-language literature through October 1999 using MEDLINE, EMBASE, other computerized databases, and hand searching.

STUDY SELECTION

All studies that compared Pap testing (conventional methods, computer screening or rescreening, or monolayer cytology) with a concurrent reference standard (histologic examination, colposcopy, or cytology).

DATA EXTRACTION

Two reviewers independently reviewed selection criteria and completed 2 x 2 tables for each study.

DATA SYNTHESIS

94 studies of the conventional Pap test and three studies of monolayer cytology met inclusion criteria. No studies of computerized screening were included. Data were organized by cytologic and histologic thresholds used to define disease. For conventional Pap tests, estimates of sensitivity and specificity varied greatly in individual studies. Methodologic quality and frequency of histologic abnormalities also varied greatly between studies. In the 12 studies with the least biased estimates, sensitivity ranged from 30% to 87% and specificity ranged from 86% to 100%.

CONCLUSIONS

Insufficient high-quality data exist to estimate test operating characteristics of new cytologic methods for cervical screening. Future studies of these technologies should apply adequate reference standards. Most studies of the conventional Pap test are severely biased: The best estimates suggest that it is only moderately accurate and does not achieve concurrently high sensitivity and specificity. Cost-effectiveness models of cervical cancer screening should use more conservative estimates of Pap test sensitivity.

A prospective follow up study of women with colposcopically unconfirmed positive cervical smears

OBJECTIVE

To examine a cohort of women with positive cervical smears, but negative colposcopy, in order to ascertain whether there is a subsequent difference in the incidence of squamous dyskaryosis and cervical intraepithelial neoplasia when compared with a control group.

DESIGN

Prospective follow up study.

SETTING

Colposcopy clinics, antenatal clinics, GP surgeries.

METHODS

A study group of 255 women with reported abnormal cervical smears but negative colposcopy was subdivided into three groups according to referral smears suggesting high grade dyskaryosis (n = 34), mild dyskaryosis (n = 120) and borderline changes (n = 101). They were followed for at least five years and were compared with a control group of 726 women followed up after a negative smear, using the first and worst follow up smears over a five year recall period.

MAIN OUTCOME MEASURES

Incidence of subsequent cervical cytological and histological abnormalities.

RESULTS

The control group had a similar incidence of squamous dyskaryosis as that expected in the screening population. Forty-six per cent of the study group with colposcopically unconfirmed ('false positive') cervical smears subsequently had abnormal smears. When the three groups were compared with controls using a chi2 test, their incidence of abnormal smears was significantly increased. Cervical intrepithelial neoplasia was found in 19% of the study group, and in 3% of the control group (P < 0.0001).

CONCLUSIONS

The analysis demonstrates that women with so-called 'false positive' smears defined by negative colposcopy have an increased risk of subsequent abnormal smears and cervical intrepithelial neoplasia, suggesting that lesions may have been missed on colposcopy. However, in a significant proportion of women, further abnormalities were not detected during the follow up period, indicating that there may be other causes for positive smears and negative colposcopy.