Table 3.
Estimated positive predicted value and number needed for colonoscopy for CRC, AA and adenomas by f-Hb thresholds (μg/g) and interscreening intervals (years).
| Threshold | Interscreening interval | Screen-detected CRC | Screen-prevented CRC | Screen-benefited CRC | AA detected | Adenomas | |||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| PPV | NNC | PPV | NNC | PPV | NNC | PPV | NNC | PPV | NNC | ||
| 20 | 1 | 1.22% | 82.1 | 0.61% | 164.3 | 1.83% | 54.7 | 10.94% | 9.1 | 23.13% | 4.3 |
| 2 | 2.07% | 48.4 | 0.93% | 107.0 | 3.00% | 33.3 | 16.44% | 6.1 | 35.53% | 2.8 | |
| 3 | 3.02% | 33.1 | 1.15% | 87.1 | 4.17% | 24.0 | 20.65% | 4.8 | 43.63% | 2.3 | |
| 4 | 3.52% | 28.4 | 1.27% | 78.7 | 4.79% | 20.9 | 23.83% | 4.2 | 48.26% | 2.1 | |
| 5 | 4.19% | 23.9 | 1.37% | 73.1 | 5.56% | 18.0 | 26.75% | 3.7 | 51.97% | 1.9 | |
| 40 | 1 | 1.90% | 52.6 | 0.72% | 138.0 | 2.63% | 38.1 | 14.24% | 7.0 | 27.54% | 3.6 |
| 2 | 3.15% | 31.8 | 1.03% | 97.1 | 4.18% | 23.9 | 20.06% | 5.0 | 39.12% | 2.6 | |
| 3 | 4.45% | 22.5 | 1.20% | 83.2 | 5.65% | 17.7 | 24.28% | 4.1 | 45.68% | 2.2 | |
| 4 | 5.08% | 19.7 | 1.29% | 77.3 | 6.38% | 15.7 | 27.32% | 3.7 | 49.14% | 2.0 | |
| 5 | 5.91% | 16.9 | 1.36% | 73.5 | 7.27% | 13.7 | 29.93% | 3.3 | 51.73% | 1.9 | |
| 80 | 1 | 3.47% | 28.8 | 0.91% | 110.2 | 4.38% | 22.8 | 19.37% | 5.2 | 34.48% | 2.9 |
| 2 | 5.40% | 18.5 | 1.16% | 86.3 | 6.56% | 15.2 | 24.92% | 4.0 | 44.04% | 2.3 | |
| 3 | 7.15% | 14.0 | 1.27% | 78.5 | 8.42% | 11.9 | 28.48% | 3.5 | 48.42% | 2.1 | |
| 4 | 7.88% | 12.7 | 1.33% | 75.3 | 9.21% | 10.9 | 30.83% | 3.2 | 50.48% | 2.0 | |
| 5 | 8.75% | 11.4 | 1.36% | 73.4 | 10.11% | 9.9 | 32.55% | 3.1 | 51.75% | 1.9 | |
| 120* | 1 | 4.86% | 20.6 | 0.97% | 103.0 | 5.84% | 17.1 | 21.92% | 4.6 | 36.89% | 2.7 |
| 2 | 7.10% | 14.1 | 1.16% | 86.3 | 8.25% | 12.1 | 26.47% | 3.8 | 44.03% | 2.3 | |
| 3 | 8.84% | 11.3 | 1.23% | 81.5 | 10.06% | 9.9 | 29.03% | 3.4 | 46.65% | 2.1 | |
| 4 | 9.42% | 10.6 | 1.26% | 79.7 | 10.67% | 9.4 | 30.61% | 3.3 | 47.71% | 2.1 | |
| 5 | 9.98% | 10.0 | 1.26% | 79.2 | 11.24% | 8.9 | 31.49% | 3.2 | 48.00% | 2.1 | |
| 150 | 1 | 5.83% | 17.1 | 0.99% | 101.2 | 6.82% | 14.7 | 22.69% | 4.4 | 37.53% | 2.7 |
| 2 | 8.29% | 12.1 | 1.14% | 87.6 | 9.43% | 10.6 | 26.61% | 3.8 | 43.40% | 2.3 | |
| 3 | 10.08% | 9.9 | 1.19% | 84.0 | 11.27% | 8.9 | 28.64% | 3.5 | 45.25% | 2.2 | |
| 4 | 10.60% | 9.4 | 1.21% | 82.8 | 11.81% | 8.5 | 29.81% | 3.4 | 45.91% | 2.2 | |
| 5 | 11.03% | 9.1 | 1.21% | 82.9 | 12.23% | 8.2 | 30.33% | 3.3 | 45.84% | 2.2 | |
| 180 | 1 | 6.79% | 14.7 | 1.00% | 99.7 | 7.79% | 12.8 | 24.12% | 4.1 | 38.13% | 2.6 |
| 2 | 9.37% | 10.7 | 1.14% | 88.1 | 10.50% | 9.5 | 27.69% | 3.6 | 43.14% | 2.3 | |
| 3 | 11.09% | 9.0 | 1.17% | 85.2 | 12.26% | 8.2 | 29.48% | 3.4 | 44.58% | 2.2 | |
| 4 | 11.50% | 8.7 | 1.19% | 84.4 | 12.69% | 7.9 | 30.51% | 3.3 | 45.04% | 2.2 | |
| 5 | 11.74% | 8.5 | 1.18% | 84.7 | 12.92% | 7.7 | 30.90% | 3.2 | 44.86% | 2.2 | |
CRC colorectal cancer, AA advanced adenomas, high-risk and intermediate-risk adenomas combined, f-Hb faecal haemoglobin concentration, PPV positive predictive value, NNC number needed to colonoscopy.
*Results for the current screening policy are in bold.