Table 2.

Size (mm), proportion of grade III cancers, and nodal status by age and screening round for screen detected and interval invasive breast cancer

Type of attendanceAge group
40-4950-6970-74≥75P*
Invasive cancer
    First screen
        Cancers (n)2451,711290242
        Mean size (mm)18.0916.1016.2715.740.15
        Grade (n)2541752294253
        Grade III (%)20.8716.6716.6713.830.09
        Nodal status (n)2541,753294254
        Node negative (%)69.2974.2276.1983.46
        Node positive (%)30.7125.7823.8116.54<0.001
    Subsequent screen
        Cancers (n)662,040469125
        Mean size (mm)17.213.8813.4013.660.08
        Grade (n)692,061478127
        Grade III (%)20.2918.1015.0613.390.05
        Nodal status (n)692,061478127
        Node negative (%)71.0180.4984.7390.55
        Node positive (%)28.9919.5115.279.45<0.001
Interval cancer
    Cancers (n)1126255924
    Mean size (mm)20.6421.3918.6120.750.52
    Grade (n)1066055522
    Grade III (%)49.0638.1830.9145.450.06
    Nodal status (n)1267056627
    Node negative (%)24.6015.7428.7940.74
    Node positive (%)75.4084.2671.2159.26<0.001
  • * Two-sided P's from a nonparametric test for trend. n, nonmissing size, nonmissing grade, and nonmissing nodes.