Table 1.
Screening results at 6 consecutive 2-year screening periods
| Screening period | 1997/1998 | 1999/2000 | 2001/2002 | 2003/2004 | 2005/2006 | 2007/2008 | Total |
|---|---|---|---|---|---|---|---|
| Mammograms, No | 48,721 | 53,718 | 53,489 | 61,251 | 66,300 | 67,530 | 351,009 |
| Referral, No | 536 | 499 | 553 | 985 | 874 | 1003 | 4450 |
| Referral rate, % (95% CI) | 1.1 (1.0-1.2) | 0.9 (0.9-1.0) | 1.0 (1.0-1.1) | 1.6 (1.5-1.7) | 1.3 (1.2-1.4) | 1.5 (1.4-1.6) | 1.3 (1.2-1.3) |
| Screen detected breast cancers, No | 224 | 274 | 254 | 345 | 321 | 353 | 1,771 |
| Advanced cancers, No (rate*; 95% CI) | 74 (1.5; 1.2-1.9) |
87 (1.6; 1.3-2.0) |
88 (1.6; 1.3-2.0) |
99 (1.6; 1.3-1.9) |
97 (1.5; 1.2-1.8) |
125 (1.9; 1.5-2.2) |
570 (1.6; 1.5-1.8) |
| Non-advanced cancers, No (rate*; 95% CI) | 147 (3.0; 2.5-3.5) |
178 (3.3; 2.8-3.8) |
160 (3.0; 2.5-3.5) |
239 (3.9; 3.4-4.4) |
218 (3.3; 2.9-3.7) |
222 (3.3; 2.9-3.7) |
1,164 (3.3; 3.1-3.5) |
| Unknown tumor stage, No (rate*; 95% CI) | 3 (0.1; 0.0-0.1) |
9 (0.2; 0.1-0.3) |
6 (0.1; 0.0-0.2) |
7 (0.1; 0.0-0.2) |
6 (0.1; 0.0-0.2) |
6 (0.1; 0.0-0.2) |
37 (0.1; 0.1-0.1) |
| Cancer detection rate* (95% CI) | 4.6 (4.0-5.2) | 5.1 (4.5-5.7) | 4.7 (4.2-5.3) | 5.6 (5.0-6.2) | 4.8 (4.3-5.4) | 5.2 (4.7-5.8) | 5.1 (4.8-5.3) |
| PPV of referral, % (95% CI) | 41.8 (37.6-46.0) | 54.9 (50.8-59.5) | 45.9 (41.9-50.2) | 35.0 (32.0-38.0) | 36.7 (33.5-39.9) | 35.2 (32.1-38.0) | 39.8 (38.3-41.2) |
| Interval cancers, No | 75 | 94 | 128 | 116 | 139 | 117 | 669 |
| Advanced cancers, No (rate*; 95% CI) | 39 (0.8; 0.5-1.1) |
63 (1.2; 0.9-1.5) |
86 (1.6; 1.3-1.9) |
79 (1.3; 1.0-1.6) |
87 (1.3; 1.0-1.6) |
70 (1.0; 0.8-1.3) |
424 (1.2; 1.1-1.3) |
| Non-advanced cancers, No (rate*; 95% CI) | 33 (0.7; 0.4-0.9) |
30 (0.6; 0.4-0.8) |
39 (0.7; 0.5-1.0) |
35 (0.6; 0.4-0.8) |
50 (0.8; 0.5-1.0) |
46 (0.7; 0.5-0.9) |
233 (0.7; 0.6-0.7) |
| Unknown tumor stage, No (rate*; 95% CI) | 3 (0.1; 0.0-0.1) |
1 (0.0; 0.0-0.1) |
3 (0.1; 0.0-0.1) |
2 (0.0; 0.0-0.1) |
2 (0.0; 0.0-0.1) |
1 (0.0; 0.0-0.0) |
12 (0.0; 0.0-0.1) |
| Sensitivity, % (95% CI) | 74.9 (70.3-80.1) | 74.5 (70.0-78.9) | 66.5 (61.8-71.2) | 74.8 (70.9-78.8) | 69.8 (65.6-74.0) | 75.1 (72.0-79.8) | 72.6 (71.0-74.5) |
| Proportion of advanced cancers among screen detected cancers + interval cancers, % (95% CI) | 37.8 (32.4-43.4) | 40.7 (36.3-46.3) | 45.5 (40.0-50.0) | 38.6 (34.2-43.1) | 39.9 (35.7-44.7) | 41.5 (37.0-46.0) | 40.7 (38.8-42.7) |
*per 1,000 women screened; CI = confidence interval; PPV = positive predictive value