Table 3

Post-screen invasive cancer rate (per 10 000 person-years) by follow-up times, service provider and region following a normal screen mammogram in study period A. Number in parenthesis is the corresponding 95% CI

RegionIntervalProviderNRateRate ratioP value
Edmonton area0–12 monthsCommunity clinics376.7 (4.8 to 9.2)
Screen test34.0 (1.3 to 12.4)
12–24 monthsCommunity clinics8222.7 (18.3 to 28.2)
Screen test57.8 (3.3 to 18.8)
Calgary area0–12 monthsCommunity clinics325.3 (3.7 to 7.4)
Screen test22.6 (0.7 to 10.6)
12–24 monthsCommunity clinics6016.0 (12.4 to 20.6)
Screen test57.9 (3.3 to 19.0)
Other areas0–12 monthsCommunity clinics2711.2 (7.7 to 16.3)
Screen test43.5 (1.3 to 9.3)
12–24 monthsCommunity clinics2215.2 (10.0 to 23.0)
Screen test77.1 (3.4 to 14.8)
Total0–12 monthsCommunity clinics966.8 (5.6 to 8.3) 2.36 0.0158
Screen test93.4 (1.8 to 6.5)(1.18 to 4.73)
12–24 monthsCommunity clinics16418.6 (16.0 to 21.7) 2.27 0.0017
Screen test177.5 (4.7 to 12.1)(1.36 to 3.78)