Time trends of some indicators of mammography screening programmes in Italy, 1996-2003.

Since 1992, the Italian Group for Mammography Screening (GISMa) has been performing a yearly systematic survey of ongoing activities. The screening extension increased from 1996, reaching an overall 68.7% coverage in 2004. This progression has been more evident in Central-Northern Italy while in Southern Italy a real, but still limited (30%), increase has been recorded only recently. Despite this geographical extension, the actual coverage reached only 5 1.1% of the target population, due to a reduced flow of invitations over time as a consequence of a chronic lack of invested resources and of well planned political actions. The time trends for the key performance indicators show a good average performance: crude attendance rate exceeds over the years the acceptable 50% standard; BIM ratio is progressively decreasing, reaching a ratio of 0.7:1 (both for first/subsequent screening) in 2003; overall detection rate, detection rate for in situ and small cancers (< or =10 mm) show a good trend, reaching 6.6% per hundred, 1.5% per hundred and 0.7% per hundred respectively for the first screening in 2003. An exception is the referral rate at first screening which exceeds the reference standards (> 7% in the last 2 years). Data have been analysed also according to activity volume and programme duration. In programmes with greater activity (average test number: 24,702) the referral rate for the first screening is higher, but still within acceptable standards: 5.8%; RR: 1.05 (1.02-1.10). This performance is compensated by better specificity and sensitivity: PPV = 13.3: RR: 1.14 (1.03-1.27); overall detection rate = 6.7% per hundred; RR: 1.22 (1.09-1.36). An improvement of quality with the increase of experience is evident: programmes with more than 6 years of activity, compared with newer programmes, show a recall rate in first screening of 6.0%; RR:0.86 (0.86-0.92), a PPV of 13.4; RR: 1.65 (1.40-1.69) and an overall detection rate of 8.1% per hundred; RR: 1.44 (1.25-1.53). These results are consistent with those observed in other European programmes, and encourage new analysis strategies. The web site of the National Centre for Monitoring Screening is http://wwuw.osservatoriotumori.it.