Time trends of process and impact indicators in Italian breast screening programmes: 1998-2007

Since its establishment in 1990, one of the main tasks of the Italian Group for Mammography Screening (GISMa) has been that of collecting, as systematically and thoroughly as possible, data on the activity of the Italian mammography screening programmes. Data are collected in an aggregated way and gathered through a standardised form to calculate process and impact parameters. Analysis of data referring to the period 1998-2007 shows that crude attendance rate reached the acceptable 50% standard, presenting a higher level of participation in Northern and Central Italy compared to Southern Italy/Islands, where attendance rates are still inadequate and do not reach the acceptable standard. In areas where the centralised management is more established or complete, the participation rate was higher compared with areas without such characteristics, with differences of about 4-9%. The time trends of the other parameters included in the analysis showed a good average performance. For example, benign/malignant surgical biopsy ratio (B/M ratio) continued to progressively decrease, reaching 0.20 at first screening and 0.10 at subsequent screening in 2007; overall detection rate, detection rate for in situ and small cancers (< or =10 mm) showed a good trend, reaching 5.4 per thousand, 0.9 per thousand, and 1.6 per thousand, respectively, for fi rst screening, and 4.8 o/oo, 0.8 o/oo, and 1.2 o/oo for subsequent screening in 2007. On the contrary, excess referral rate at first screening persists over time. Data comparing activity volume and programme duration were also considered. In programmes with greater activity volume (average test number: 24,596) the referral rate for first screening was higher if compared with programmes with lower activity volume, but still within acceptable standards. Nevertheless, this performance is compensated by better specificity and sensitivity. An improvement in quality with the increase of programmes experience continues to be evident: compared with new programmes, programmes with more than 6 years of activity showed lower recall rates, higher positive predictive values and higher overall detection rates in the first screening round. Outcomes related to subsequent screening rounds present analogous performances. These results continue to be consistent with those achieved by other European programmes and reassuring for all Italian mammography screening professionals.