Table 3.
Interval cancer rate by age group, breast density and presence or absence of all other risk factors (calculated for each screening episode).
| Age | None of the RFs∗ |
At least one RF∗ |
||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Not dense breasts |
Dense breasts |
Not dense breasts |
Dense breasts |
|||||||||||||
| Total | Cancer | ICR | 95% CI | Total | Cancer | ICR | 95% CI | Total | Cancer | ICR | 95% CI | Total | Cancer | ICR | 95% CI | |
| 40–49 | 49385 | 48 | 4.9 | 3.7–6.5 | 33226 | 91 | 13.8 | 11.3–17.0 | 26563 | 42 | 8.9∗∗ | 6.6–12.0 | 21701 | 75 | 19.2 | 15.3–24.1 |
| 50–59 | 171322 | 183 | 5.4 | 4.7–6.2 | 57133 | 151 | 13.4 | 11.4–15.7 | 114117 | 172 | 8.3∗∗ | 7.1–9.6 | 50254 | 173 | 18.7 | 16.1–21.7 |
| 60–69 | 154107 | 185 | 6.1 | 5.3–7.0 | 27683 | 78 | 14.3 | 11.4–17.8 | 112851 | 191 | 9.4∗∗ | 8.2–10.8 | 31528 | 139 | 24.3 | 20.5–28.7 |
| 70 and over | 41390 | 63 | 7.7 | 6.0–9.9 | 6247 | 21 | 17.0 | 11.1–26.1 | 33439 | 74 | 12.2∗∗ | 9.7–15.4 | 7683 | 48 | 34.3 | 25.9–45.5 |
RF, risk factor; ICR, interval cancer rate per 10,000 women-years; CI, confidence interval. ∗First-degree family history of breast cancer, HRT use, history of benign breast conditions, and self-reporting symptoms. ∗∗Difference to the ‘None of the RFs, No dense breasts’ group in the same age group is statistically significant.