Introduction
Materials and methods
Singapore breast cancer screening project
Study population
Formation of Gail model risk factor categories
Statistical methods
Results
Total | Cases (all breast cancer) | Controls | P value | ||||
---|---|---|---|---|---|---|---|
Number | Percentage | Number | Percentage | Number | Percentage | ||
Total | 28,104 | 100.0 | 575 | 100.0 | 27,529 | 100.0 | |
Age at menarche, years | |||||||
≥ 14 | 18,237 | 64.9 | 324 | 56.3 | 17,913 | 65.1 | < 0.001 |
12-13 | 8,952 | 31.9 | 213 | 37.0 | 8,739 | 31.7 | |
< 12 | 915 | 3.3 | 38 | 6.6 | 877 | 3.2 | |
Any breast biopsy Age at screening: ≥50 years | |||||||
No | 26,631 | 94.8 | 514 | 89.4 | 26,117 | 94.9 | < 0.001 |
Yes | 1,473 | 5.2 | 61 | 10.6 | 1,412 | 5.1 | |
Number of affected first-degree relatives Age at first live birth: < 20 years | |||||||
0 | 4,753 | 16.9 | 68 | 11.8 | 4,685 | 17.0 | < 0.001b |
1 | 89 | 0.3 | 3 | 0.5 | 86 | 0.3 | |
> 1 | 1 | 0.0 | 0 | 0.0 | 1 | 0.0 | |
Number of affected first-degree relatives Age at first live birth: 20-24 years | |||||||
0 | 10,321 | 36.7 | 149 | 26.3 | 10,172 | 37.0 | |
1 | 216 | 0.8 | 13 | 2.1 | 203 | 0.7 | |
> 1 | 6 | 0.0 | 2 | 0.3 | 4 | 0.0 | |
Number of affected first-degree relatives Age at first live birth: 25-29 years or nulliparous | |||||||
0 | 9,246 | 32.9 | 230 | 40.0 | 9,016 | 32.8 | |
1 | 303 | 1.1 | 17 | 3.0 | 286 | 1.0 | |
> 1 | 4 | 0.0 | 0 | 0.0 | 4 | 0.0 | |
Number of affected first-degree relatives Age at first live birth: > 30 years | |||||||
0 | 3,059 | 10.9 | 85 | 14.8 | 2,974 | 10.8 | |
1 | 105 | 0.4 | 7 | 1.2 | 98 | 0.4 | |
> 1 | 1 | 0.0 | 1 | 0.2 | 0 | 0.0 |
Risk factors | Based on SBCSP (95% CI) | Gail model: BCDDP (95% CI) |
---|---|---|
Age at menarche, years | ||
≥14 | 1.00 (referent) | 1.00 (referent) |
12-13 | 1.39 | 1.10 |
< 12 | 1.95 | 1.21 |
Any breast biopsy Age at screening: ≥50 years | ||
No | 1.00 (referent) | 1.00 (referent) |
Yes | 1.97 | 1.28a |
Number of affected first-degree relatives Age at first live birth: < 20 years | ||
0 | 1.00 (referent) | 1.00 (referent) |
1 | 3.61 | 2.61 |
> 1 | 13.04 | 6.80 |
Number of affected first-degree relatives Age at first live birth: 20-24 years | ||
0 | 1.33 | 1.24 |
1 | 4.14 | 2.68 |
> 1 | 12.91 | 5.78 |
Number of affected first-degree relatives Age at first live birth: 25-29 years or nulliparous | ||
0 | 1.76 | 1.55 |
1 | 4.75 | 2.76 |
> 1 | 12.79 | 4.91 |
Number of affected first-degree relatives Age at first live birth: > 30 years | ||
0 | 2.34 | 1.93 |
1 | 5.44 | 2.83 |
> 1 | 12.67 | 4.17 |
Risk factors | Based on Gail model (Caucasian) | Based on Matsuno AABCS model (Chinese-American and other Asian-American) | ||||||
---|---|---|---|---|---|---|---|---|
O | E | E/O | 95% CI for E/O | O | E | E/O | 95% CI for E/O | |
Total | 144 | 362.08 | 2.51 | (2.14, 2.96) | 144 | 205.95 | 1.43 | (1.21, 1.68) |
Age at menarche, years | ||||||||
≥ 14 | 89 | 228.92 | 2.57 | (2.09, 3.17) | 89 | 129.13 | 1.45 | (1.18, 1.79) |
12-13 | 47 | 119.66 | 2.55 | (1.91, 3.39) | 47 | 69.23 | 1.47 | (1.11, 1.96) |
< 12 | 8 | 13.50 | 1.69 | (0.84, 3.37) | 8 | 7.60 | 0.95 | (0.48, 1.90) |
χ2 = 131.88, P < 0.001 | χ2 = 19.63, P < 0.001 | |||||||
Any breast biopsy Age at screening: ≥50 years | ||||||||
No | 129 | 337.48 | 2.62 | (2.20, 3.11) | 129 | 186.43 | 1.45 | (1.22, 1.72) |
Yes | 15 | 24.60 | 1.64 | (0.99, 2.72) | 15 | 19.53 | 1.30 | (0.78, 2.16) |
χ2 = 132.54, P < 0.001 | χ2 = 18.74, P < 0.001 | |||||||
Number of affected first-degree relatives Age at first live birth: < 20 years | ||||||||
0 | 17 | 44.89 | 2.64 | (1.64, 4.25) | 17 | 21.22 | 1.25 | (0.78, 2.01) |
1 | 0 | 2.23 | - | - | 0 | 0.90 | - | - |
> 1 | 0 | 0.07 | - | - | 0 | 0.01 | - | - |
Number of affected first-degree relatives Age at first live birth: 20-24 years | ||||||||
0 | 39 | 118.36 | 3.03 | (2.22, 4.15) | 39 | 62.73 | 1.61 | (1.18, 2.20) |
1 | 4 | 5.27 | 1.32 | (0.49, 3.51) | 4 | 2.98 | 0.75 | (0.28, 1.99) |
> 1 | 0 | 0.30 | - | - | 0 | 0.08 | - | - |
Number of affected first-degree relatives Age at first live birth: 25-29 years or nulliparous | ||||||||
0 | 54 | 127.92 | 2.37 | (1.81, 3.09) | 54 | 76.46 | 1.42 | (1.08, 1.85) |
1 | 3 | 7.54 | 2.51 | (0.81, 7.79) | 3 | 5.71 | 1.90 | (0.61, 5.90) |
> 1 | 0 | 0.18 | - | - | 0 | 0.07 | - | - |
Number of affected first-degree relatives Age at first live birth: > 30 years | ||||||||
0 | 24 | 52.62 | 2.19 | (1.47, 3.27) | 24 | 33.19 | 1.38 | (0.93, 2.06) |
1 | 2 | 2.68 | 1.34 | (0.34, 5.36) | 2 | 2.58 | 1.29 | (0.32, 5.16) |
> 1 | 1 | 0.04 | 0.04 | (0.01, 0.28) | 1 | 0.04 | 0.04 | (0.01, 0.28) |
χ2 = 157.85, P < 0.001 | χ2 = 44.82, P < 0.001 |
Based on Gail model (Caucasian) | Based on Matsuno AABCS model (Chinese-American and other Asian-American) | |||||||
---|---|---|---|---|---|---|---|---|
O | E | E/O | 95% CI for E/O | O | E | E/O | 95% CI for E/O | |
Total | 144 | 362.08 | 2.51 | (2.14, 2.96) | 141 | 205.95 | 1.46 | (1.24, 1.72) |
5-year age at screening group | ||||||||
50-54 years | 44 | 94.48 | 2.15 | (1.60, 2.89) | 44 | 64.39 | 1.46 | (1.09, 1.97) |
55-59 years | 62 | 133.36 | 2.15 | (1.68, 2.76) | 62 | 79.48 | 1.28 | (1.00, 1.64) |
60-64 yearsa | 38 | 134.23 | 3.53 | (2.57, 4.85) | 38 | 60.07 | 1.58 | (1.15, 2.17) |
χ2 = 134.14, P < 0.001 | χ2 = 18.41, P < 0.001 | |||||||
5-year predicted risk groupb | ||||||||
1%-20% | 20 | 49.83 | 2.49 | (1.61, 3.86) | 16 | 25.16 | 1.57 | (0.96, 2.57) |
21%-40% | 27 | 60.63 | 2.25 | (1.54, 3.27) | 19 | 32.31 | 1.70 | (1.08, 2.67) |
41%-60% | 29 | 69.25 | 2.39 | (1.66, 3.44) | 29 | 37.64 | 1.30 | (0.90, 1.87) |
61%-80% | 23 | 78.41 | 3.41 | (2.27, 5.13) | 29 | 45.24 | 1.56 | (1.08, 2.24) |
81%-100% | 45 | 103.96 | 2.31 | (1.72, 3.09) | 51 | 65.60 | 1.29 | (0.98, 1.69) |
χ2 = 132.50, P < 0.001 | χ2 = 19.88, P = 0.001 | |||||||
5-year age at screening group, 5-year predicted risk groupb | ||||||||
50-54 years | ||||||||
1%-20% | 10 | 28.00 | 2.80 | (1.51, 5.20) | 2 | 7.07 | 3.54 | (0.88, 14.13) |
21%-40% | 8 | 21.01 | 2.63 | (1.31, 5.25) | 5 | 6.02 | 1.20 | (0.50, 2.89) |
41%-60% | 13 | 20.22 | 1.56 | (0.90, 2.68) | 10 | 13.68 | 1.37 | (0.74, 2.54) |
61%-80% | 7 | 13.4 | 1.91 | (0.91, 4.02) | 10 | 14.62 | 1.46 | (0.79, 2.72) |
81%-100% | 6 | 11.86 | 1.98 | (0.89, 4.40) | 17 | 22.99 | 1.35 | (0.84, 2.18) |
55-59 years | ||||||||
1%-20% | 7 | 17.96 | 2.57 | (1.22, 5.38) | 6 | 8.46 | 1.41 | (0.63, 3.14) |
21%-40% | 14 | 26.54 | 1.90 | (1.12, 3.20) | 9 | 8.43 | 0.94 | (0.49, 1.80) |
41%-60% | 11 | 22.76 | 2.07 | (1.15, 3.74) | 12 | 15.52 | 1.29 | (0.73, 2.28) |
61%-80% | 10 | 31.77 | 3.18 | (1.71, 5.90) | 14 | 19.48 | 1.39 | (0.82, 2.35) |
81%-100% | 20 | 34.33 | 1.72 | (1.11, 2.66) | 21 | 27.59 | 1.31 | (0.86, 2.02) |
60-64 yearsa | ||||||||
1%-20% | 3 | 3.85 | 1.28 | (0.41, 3.98) | 8 | 9.62 | 1.20 | (0.60, 2.40) |
21%-40% | 5 | 13.09 | 2.62 | (1.09, 6.29) | 5 | 17.86 | 3.57 | (1.49, 8.58) |
41%-60% | 5 | 26.27 | 5.25 | (2.19, 12.62) | 7 | 8.44 | 1.21 | (0.57, 2.53) |
61%-80% | 6 | 33.24 | 5.54 | (2.49, 12.33) | 5 | 11.14 | 2.23 | (0.93, 5.35) |
81%-100% | 19 | 57.78 | 3.04 | (1.94, 4.77) | 13 | 15.01 | 1.15 | (0.67, 1.99) |
χ2 = 138.51, P < 0.001 | χ2 = 25.92, P = 0.027 |
Risk factors | Based on Gail model (Caucasian) | Based on Matsuno AABCS model (Chinese-American and other Asian-American) | ||||||
---|---|---|---|---|---|---|---|---|
O | E | E/O | 95% CI for E/O | O | E | E/O | 95% CI for E/O | |
Total | 409 | 758.18 | 1.85 | (1.68, 2.04) | 409 | 404.70 | 0.99 | (0.90, 1.09) |
Age at menarche, years | ||||||||
≥14 | 226 | 477.32 | 2.11 | (1.85, 2.41) | 226 | 253.58 | 1.12 | (0.98, 1.28) |
12-13 | 161 | 252.42 | 1.57 | (1.34, 1.83) | 161 | 136.16 | 0.85 | (0.72, 0.99) |
< 12 | 22 | 28.44 | 1.29 | (0.85, 1.96) | 22 | 14.96 | 0.68 | (0.45, 1.03) |
χ2 = 166.89, P < 0.001 | χ2 = 10.84, P = 0.004 | |||||||
Any breast biopsy Age at screening: ≥50 years | ||||||||
No | 370 | 706.46 | 1.91 | (1.72, 2.11) | 370 | 366.38 | 0.99 | (0.89, 1.10) |
Yes | 39 | 51.72 | 1.33 | (0.97, 1.82) | 39 | 38.32 | 0.98 | (0.72, 1.34) |
χ2 = 163.37, P < 0.001 | χ2 = 0.05, P = 0.827 | |||||||
Number of affected first-degree relatives Age at first live birth: < 20 years | ||||||||
0 | 48 | 93.42 | 1.95 | (1.47, 2.58) | 48 | 41.62 | 0.87 | (0.65, 1.15) |
1 | 2 | 4.59 | 2.30 | (0.57, 9.18) | 2 | 1.76 | 0.88 | (0.22, 3.52) |
> 1 | 0 | 0.13 | - | - | 0 | 0.02 | - | - |
Number of affected first-degree relatives Age at first live birth: 20-24 years | ||||||||
0 | 113 | 246.74 | 2.18 | (1.82, 2.63) | 113 | 123.47 | 1.09 | (0.91, 1.31) |
1 | 9 | 10.97 | 1.22 | (0.63, 2.34) | 9 | 5.84 | 0.65 | (0.34, 1.25) |
> 1 | 2 | 0.62 | 0.31 | (0.08, 1.24) | 2 | 0.15 | 0.08 | (0.02, 0.30) |
Number of affected first-degree relatives Age at first live birth: 25-29 years or nulliparous | ||||||||
0 | 156 | 269.37 | 1.73 | (1.48, 2.02) | 156 | 150.21 | 0.96 | (0.82, 1.13) |
1 | 13 | 15.78 | 1.21 | (0.70, 2.09) | 13 | 11.19 | 0.86 | (0.50, 1.48) |
> 1 | 0 | 0.36 | - | - | 0 | 0.14 | - | - |
Number of affected first-degree relatives Age at first live birth: > 30 years | ||||||||
0 | 62 | 110.49 | 1.78 | (1.39, 2.29) | 62 | 65.18 | 1.05 | (0.82, 1.35) |
1 | 3 | 5.61 | 1.87 | (0.60, 5.80) | 3 | 5.04 | 1.68 | (0.54, 5.21) |
> 1 | 1 | 0.09 | 0.09 | (0.01, 0.64) | 1 | 0.08 | 0.08 | (0.01, 0.57) |
χ2 = 179.85, P < 0.001 | χ2 = 38.66, P < 0.001 |
Based on Gail model (Caucasian) | Based on Matsuno AABCS model (Chinese-American and other Asian-American) | |||||||
---|---|---|---|---|---|---|---|---|
O | E | E/O | 95% CI for E/O | O | E | E/O | 95% CI for E/O | |
Total | 409 | 758.18 | 1.85 | (1.68, 2.04) | 409 | 404.70 | 0.99 | (0.90, 1.09) |
5-year age at screening group | ||||||||
50-54 years | 135 | 205.49 | 1.52 | (1.29, 1.80) | 135 | 128.96 | 0.96 | (0.81, 1.13) |
55-59 years | 168 | 283.71 | 1.69 | (1.45, 1.96) | 168 | 153.13 | 0.91 | (0.78, 1.06) |
60-64 yearsa | 106 | 268.94 | 2.54 | (2.10, 3.07) | 106 | 122.58 | 1.16 | (0.96, 1.40) |
χ2 = 170.09, P < 0.001 | χ2 = 3.97, P = 0.137 | |||||||
5-year predicted risk groupb | ||||||||
1%-20% | 62 | 107.19 | 1.73 | (1.35, 2.22) | 49 | 49.33 | 1.01 | (0.76, 1.33) |
21%-40% | 70 | 128.26 | 1.83 | (1.45, 2.32) | 55 | 64.54 | 1.17 | (0.90, 1.53) |
41%-60% | 60 | 144.77 | 2.41 | (1.87, 3.11) | 82 | 74.29 | 0.91 | (0.73, 1.12) |
61%-80% | 89 | 163.95 | 1.84 | (1.50, 2.27) | 86 | 88.32 | 1.03 | (0.83, 1.27) |
81%-100% | 128 | 214.00 | 1.67 | (1.41, 1.99) | 137 | 128.21 | 0.94 | (0.79, 1.11) |
χ2 = 163.98, P < 0.001 | χ2 = 2.88, P = 0.579 | |||||||
5-year age at screening group 5-year predicted risk groupb | ||||||||
50-54 years | ||||||||
1%-20% | 29 | 56.55 | 1.95 | (1.36, 2.81) | 8 | 11.85 | 1.48 | (0.74, 2.96) |
21%-40% | 28 | 38.62 | 1.38 | (0.95, 2.00) | 13 | 13.00 | 1.00 | (0.58, 1.72) |
41%-60% | 19 | 37.93 | 2.00 | (1.27, 3.13) | 35 | 24.69 | 0.71 | (0.51, 0.98) |
61%-80% | 35 | 39.24 | 1.12 | (0.80, 1.56) | 28 | 32.03 | 1.14 | (0.79, 1.66) |
81%-100% | 24 | 33.15 | 1.38 | (0.93, 2.06) | 51 | 47.37 | 0.93 | (0.71, 1.22) |
55-59 years | ||||||||
1%-20% | 21 | 32.73 | 1.56 | (1.02, 2.39) | 22 | 17.32 | 0.79 | (0.52, 1.20) |
21%-40% | 35 | 65.44 | 1.87 | (1.34, 2.60) | 22 | 19.19 | 0.87 | (0.57, 1.32) |
41%-60% | 21 | 29.51 | 1.41 | (0.92, 2.16) | 29 | 29.55 | 1.02 | (0.71, 1.47) |
61%-80% | 36 | 78.42 | 2.18 | (1.57, 3.02) | 38 | 35.81 | 0.94 | (0.69, 1.30) |
81%-100% | 55 | 77.60 | 1.41 | (1.08, 1.84) | 57 | 51.26 | 0.90 | (0.69, 1.17) |
60-64 yearsa | ||||||||
1%-20% | 12 | 17.87 | 1.49 | (0.85, 2.62) | 19 | 20.15 | 1.06 | (0.68, 1.66) |
21%-40% | 7 | 24.20 | 3.46 | (1.65, 7.25) | 20 | 32.35 | 1.62 | (1.04, 2.51) |
41%-60% | 20 | 77.33 | 3.87 | (2.49, 5.99) | 18 | 20.02 | 1.11 | (0.70, 1.77) |
61%-80% | 18 | 46.29 | 2.57 | (1.62, 4.08) | 20 | 20.48 | 1.02 | (0.66, 1.59) |
81%-100% | 49 | 103.25 | 2.11 | (1.59, 2.79) | 29 | 29.58 | 1.02 | (0.71, 1.47) |
χ2 = 181.57, P < 0.001 | χ2 = 13.81, P = 0.464 |