ObjectiveTo compare the results of five years of annual mammography screening at age 45-49 with the results five years of biennial screening at age 50-54 and 55-69. Methods In an Italian screening programme, data from 1,465,335 mammograms were analysed. Recall rates, invasive assessment rates, surgical biopsy rates, and cancer detection rates were calculated for the first screen (first) and, cumulatively, for the second and subsequent screens (second+).
ResultsThe rate ratios between younger women and the two groups of older ones were: recall rate: first 1.11 and 1.11, second+ 2.10 and 2.77; invasive assessment rate: first 0.94 and 0.94, second+ 1.63 and 1.56; surgical biopsy rate: first 0.68 and 0.45, second+ 1.35 and 0.88; total detection rate: first 0.63 and 0.37, second+ 1.30 and 0.74. For the total positive predictive value of surgical biopsy, the ratios were: first 0.93 and 0.82, second+ 0.96 and 0.83. Both at the first and second+ screens, stage distribution of screen-detected cancers did not vary by age group. Conclusion Five years of annual screening at age 45-49 were associated with 2-3-fold higher cumulative recall rates at second+ screens and with more limited differences in the frequency and positive predictive value of surgical biopsy.