No abstract

The study was aimed at assessing interlaboratory reproducibility in the reporting of cervical smears in the atypical squamous cells of undetermined significance (ASCUS) category. A set of 50 selected slides circulated among 89 laboratories, currently involved in population-based screening programmes for cervical cancer, which provided a diagnostic report according to four main reporting categories based on the 1991 Bethesda system. Interlaboratory agreement was determined according to kappa (K) statistics: overall and weighted K values were determined for each laboratory and for single reporting categories. The results showed a very low reproducibility for the ASCUS category. This finding supports the Bethesda system 1991 recommendation to limit the use of this reporting category and suggests that the clinical response to ASCUS reports should be decided locally, based on the observed positive predictive value for cervical intraepithelial neoplasia 2 or more severe lesions.

The present study shows that the AGC category is not easily reproducible. The data confirmed the importance, in a screening scenario, of AGC/AIS diagnoses, but also presented difficulties in differentiating between the two diagnoses. In addition to the results obtained from the circulation of the slides, laboratories which had annually a low number of cervical smears were able to gain experience focused on particular morphological pictures.

After an organised cervical screening programme was introduced in Turin in 1992, the age-adjusted cervical cancer incidence ratio in 1992 -98 was 0.81 (95% confidence interval (CI) 0.59 -1.09) for invited vs not invited women and 0.25 (95% CI 0.13 -0.50) for attenders vs non attenders. An organised screening programme can further reduce cervical cancer incidence in an area where substantial spontaneous activity was previously present. There is clear evidence of efficacy for cervical cancer screening (IARC, 2005). High effectiveness and cost-effectiveness were obtained in Nordic countries, where cervical screening was organised from the outset (Laara et al, 1987). In the United Kingdom, a relevant reduction in cervical cancer mortality followed reorganisation (Sasieni and Adams, 1999;Peto et al, 2004), There is however little experience of the impact of moving from opportunistic activity to an organised programme.For many years, cervical cancer screening in Italy was almost only opportunistic (Segnan et al, 2000). An organised programme started in Turin in 1992, the main changes being (a) an active callrecall system, (b) protocols for diagnosis and treatment, (c) a failsafe system for both these phases and (d) monitoring and intensive quality assurance for every step of the screening process.In order to evaluate the impact of these changes on invasive cervical cancer incidence, we linked the screening registry to the local population cancer registry. MATERIALS AND METHODSFrom June 1992, female Turin inhabitants aged 25 -64 years were invited, irrespective of their previous spontaneous screening history, for a Pap-test, with 3-year intervals for screen-negatives. Activation was progressive: in 1996, about 78% of the target population had been invited and in 1998, about 95%. The order of invitation was substantially random, with some stratification by area (women were enrolled by general practitioners, who were selected with balance by location of practice).About one-third of invited women attended the organised programme. Attenders mostly had not had spontaneous recent cytology. As a combined result of organised and opportunistic screening, we estimated a 74% 3-year overall coverage (Ronco et al, 1997) vs 40% before the start of the programme (Segnan et al, 1990).We computed cervical cancer incidence for women aged 24 -69 years in the following groups: not invited (not yet having received the first invitation in the organised programme), invited (having already received the first invitation), attenders (invited women with at least one cytology in the organised programme), nonattenders (invited women with no cytology in the organised programme).Person-years (py) at risk of cervical cancer for the last three categories were calculated using the computerised screening registry. It was not possible to consider the screening history outside the organised programme. Each woman contributed to the 'invited' cohort from first invitation to the end of follow-up, that is, the earliest among (a) diagnosis of cervical cancer, ...

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 positive' 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.