The impact of organised screening programmes on the stage-specific incidence of XXXX in some Italian areas.

@entity1 @entity5 @entity0
The aim of this study was to examine the effects of mammographic screening programmes on stage-specific incidence of @entity0 . The study compared prescreening and screening periods in seven areas in Italy, primarily evaluating the first screening round. All 17617 @entity0 (16554 invasive, 1063 in situ) registered in @entity1 aged 40-79 years between 1988 and 1999 were analysed through age-standardised rates and Poisson regression models. For all areas, independent of the baseline rates, the introduction of screening increased incidence for invasive @entity5 overall and, more markedly, for @entity5 (screening/prescreening ratio: range 1.07-1.47 and 1.23-1.82, respectively), modifying the pattern of age-specific rates. The multiple regression analysis showed that the percentage of cases diagnosed at screening explained most of the increase; a residual effect of diagnosis period (screening versus prescreening) suggested a role for 'spontaneous' early detection in ages outside of the screening programme. Advanced cases did not show consistent variations across the registries for those aged 40-79 years (range: 0.91-1.21), whereas a more coherent picture was observed for those aged 50-69 years. In one area, a moderate reduction in the number of 'advanced' cases in the second screening period was observed. For all stages, the age-specific incidence rates of cases diagnosed outside of the screening programme for the age groups 50-69 years were lower than the corresponding rates in the prescreening period, suggesting a shift from the usual clinical services to the screening programme. Our results confirmed the increase in early-stage @entity5 occurring at the start of screening, and substantially explained the rise in @entity0 incidence. In addition, our study confirms the importance of @entity5 registries in monitoring the effect of @entity0 screening and the validity, for this purpose, of the linkage between @entity5 registries and screening programme databases.
