Accuracy of Pap tests reported as CIN I

Papanicolaou (Pap) tests reported as CIN I (cervical intraepithelial neoplasia, grade 1) may be subject to laboratory misclassification because of screening and interpretative errors. A peer-groupC consensus review was conducted to measure the misclassification rate of Pap tests reported as CIN I and to analyze the undercalled and overcalled tests for due cause. Four hundred and forty-nine Pap tests originally reported as CIN I were independently reviewed twice by a panel of four pathologists, and disagreements were resolved by consensus review. Results were based on the original screening for the first review and, following the removal of those markings, were based on a second, independent rescreening for the second review. A review result of low-grade squamous intraepithelial lesion (LSIL) and atypical squamous cells of undetermined significance (ASCUS) favoring LSIL was equated with the original CIN I result. Final classification was based on the second consensus review. Misclassified tests were categorized as screening or interpretative errors, based on a comparison of the review classifications. LSIL and ASCUS favoring LSIL were reported in 85.1% and 73.9% of the first and second reviews, respectively. In the final classification there were 362 (80.6%) LSIL and ASCUS-LSIL and 87 (19.4%) misclassifications: 31 (6.9%) undercalls and 56 (12.5%) overcalls. Screening error accounted for 35.5% of undercalled tests, and the remainder were interpretative errors, as were all those overcalled. In this study, Pap tests reported as CIN I were subject to misclassification because of a laboratory error in 19.4% of tests. Reductions in screening and interpretative errors were identified as mechanisms for improving accuracy. Diagn. Cytopathol. 1999;21:129-136.

The short-term financial costs of abnormal Pap smears to women and government in Australia

Using data collected from a private Canberra colposcopy service, we examined the direct costs, to women and government, of the gynaecological care of women with cervical cytological abnormalities and determine the potential savings of implementing the Commonwealth recommendations for the clinical care of women with screen-detected abnormalities. We performed a case note audit of 502 women who first attended a gynaecologist because of an abnormal Pap smear between 1 January 1989 and 30 April 1990. The smear resulting in their referral--their presenting smear--was categorised as No CIN (showing no evidence of cervical intraepithelial neoplasia), CIN 1, CIN 2 and CIN 3. The average costs to government (p for trend < 0.001) and women (p for trend = 0.006) increase as the presenting smear increases in severity; the median costs to government (p for trend < 0.001) and women (p for trend < 0.001) also rose with increasing cytological severity. Treatment of CIN 1 and No CIN accounted for half the costs incurred by government and women. Although costs increase with increasing severity of cytological abnormality, adherence to new Australian guidelines for the gynaecological care of women with screen-detected cervical abnormalities could result in substantial short-term savings to government and women.

Progression and regression of low-grade epithelial abnormalities of the cervix

The records of 738 women with low-grade cervical epithelial abnormalities were examined for changes in degree of cervical disease and lesion size, as well as sociodemographic and behavioural factors which influence the development of invasive cancer of the cervix. Survival analysis was used to determine the predictors and rates of progression and regression. The results suggest that about 80% of the low-grade epithelial abnormalities of the cervix will not progress within 2 years. The only predictors of progression were a biopsy diagnosis of CIN 1 and the size of the lesion. Predictors of regression were older age, older age at first intercourse, greater parity, fewer sexual partners, and absence of a past history of genital herpes. Although progression rates of low-grade abnormalities of the cervix were very low, CIN 1 lesions were 2.4 times (95% CI: 1.6 to 3.7) more likely to progress than lower-grade lesions and large lesions (> 1/2 ectocervix) were 2.0 times (95% CI: 1.2 to 3.3) more likely to progress than small ones (< 1/4 ectocervix).

Mild cervical atypia: a management dilemma

This study examined 117 patients with mild cervical atypia or atypical squamous cells of uncertain significance; it was found that 25% had histologically proven CIN lesions by colposcopically-directed punch biopsy or cone biopsy. 18% were found to have at least CIN 2 lesions and there was 1 case of invasive cancer. These data strongly support the recommendation of early colposcopic referral in patients with mild cervical atypia.

Predicting nonattendance for colposcopy clinic follow-up after referral for an abnormal Pap smear

This is retrospective cohort study of women who were recommended for further assessment or treatment after their first visit to a gynaecologist for an abnormal Pap smear. The sample included women who first attended a private outpatient colposcopy service in Canberra between 1 January 1989 and 30 April 1990. Only women who had never previously seen a gynaecologist for an abnormal Pap smear were included in the sample. The nonattendance rate was 2.2 women per 100 women-months (n = 493). Cox proportional hazards modelling was used to examine the relationships between sociodemographic and clinic variables and nonattendance. After adjusting for age and the degree of abnormality on presenting smear, women without private health insurance and women who had had treatment were less likely to continue attending. The current focus on identifying barriers to screening services needs to be broadened to consider attendance at all points along the screening pathway.

Consequences of current patterns of Pap smear and colposcopy use

OBJECTIVES - To describe age specific frequencies of Pap smear and colposcopy use in the Australian Capital Territory (ACT) and to estimate the cumulative effects of current patterns of use. SETTING - Frequencies of Pap smear and colposcopy use were estimated for the financial year from 1 July 1989 to 30 June 1990. Eligible women were between the ages of 15 and 74, living in the ACT. METHODS - Data collected from a 10% sample of subjects enrolled with Medicare and from the only public pathology laboratory in the ACT were used to estimate age specific frequencies. The expected number of deaths from cervical cancer in the ACT in the absence of a screening programme was estimated by applying Australian age specific mortality rates for cervical cancer between 1960 and 1964 to the 1989 ACT population. A life table approach was used to simulate the cumulative risk of colposcopy - given current age specific rates - on a hypothetical cohort of 1000, 15 year old women. RESULTS - Forty four per cent (95% confidence interval (CI) 42.9 to 44.9) of women had a Pap smear and 2.5% had colposcopy (95% CI 2.4 to 2.6). Two and a half percent of 15 to 24 year old women had colposcopy (95% CI 1.9 to 3.1). The ratio of women having Pap smears to women having colposcopy was 17-8:1 (95% CI 17.7 to 17.9). An estimated 247 women had colposcopy for every cervical cancer death; in the 15 to 24 year old age group this ratio was 47900:1. A 15 year old woman exposed to current rates of colposcopy (adjusted for hysterectomy) has a 76.8% chance of having a colposcopy during her life time. CONCLUSIONS - Many more women will have colposcopy than will develop cervical cancer, which undermines the cost effectiveness of Australia's cervical cancer screening programme.