Table 1. List of parameter and derived parameter estimates from (a) 13-state model and (b) 11-state model.
| (a) 13-state model | (b) 11-state model | |||
|---|---|---|---|---|
|
Parameters |
Estimates |
95% CI |
Estimates |
95% CI |
| Probability (%) of getting aggressive breast cancer |
91 |
85–97 |
— |
— |
|
Incidence rate (per 10 000 woman-years) | ||||
| Breast cancer | 21 | 17–25 | 21 | 17–25 |
| Indolent breast cancer | 2 | 1–3 | — | — |
| Aggressive breast cancer |
19 |
16–23 |
— |
— |
|
Initial probability (%) | ||||
| No cancer | 99.23 | 99.13–99.32 | 99.24 | 99.14–99.33 |
| Indolent DCIS | 0.06 | 0.03–0.09 | 0.10 | 0.05–0.15 |
| Aggressive DCIS | 0.13 | 0.01–0.32 | 0.10 | 0.05–0.15 |
| ⩽10 mm | 0.21 | 0.02–0.35 | 0.29 | 0.22–0.37 |
| 11–20 mm | 0.26 | 0.20–0.33 | 0.25 | 0.20–0.32 |
| 21–50 mm | 0.10 | 0.07–0.14 | 0.10 | 0.10–0.14 |
| ⩾51 mm |
0.02 |
0.00–0.03 |
0.02 |
0.00–0.03 |
|
Average sojourn time, in years, for different tumour sizes | ||||
| Aggressive DCIS | 0.0 | 0.0–0.1 | 0.2 | 0.1–0.4 |
| ⩽10 mm | 0.8 | 0.6–1.1 | 0.8 | 0.6–1.1 |
| 11–20 mm | 2.4 | 1.6–3.5 | 2.4 | 1.6–3.4 |
| 21–50 mm | 6.4 | 2.5–15.6 | 6.4 | 2.6–15.5 |
| ⩾51 mm |
0.4 |
0.1–0.9 |
0.5 |
0.1–0.9 |
|
Probability (%) of detecting breast cancer before progression in tumour size | ||||
| Aggressive DCIS → ⩽10 mm | 0 | 0–1 | 3 | 1–4 |
| ⩽10 mm → 11–20 mm | 12 | 8–15 | 11 | 8–15 |
| 11–20 mm → 21–50 mm | 51 | 43–60 | 51 | 43–59 |
| 21–50 mm → ⩾51 mm |
87 |
79–95 |
87 |
78–95 |
|
Probability (%) of attending screenings | ||||
| First screening | 89 | 88–89 | 89 | 88–89 |
| Both screenings | 87 | 86–87 | 87 | 86–87 |
| Second screening but not first screening |
17 |
16–19 |
17 |
16–19 |
|
Sensitivity (%) of mammography for different tumour sizes | ||||
| DCIS | 88 | 83–92 | 88 | 83–92 |
| ⩽10 mm | 90 | 86–93 | 90 | 87–93 |
| 11–20 mm | 91 | 88–94 | 91 | 88–94 |
| 21–50 mm | 92 | 89–95 | 92 | 89–95 |
| ⩾51 mm |
93 |
90–96 |
93 |
90–96 |
|
Absorption probability of different tumour sizes | ||||
| DCIS (indolent or aggressive) | 9 | 4–15 | 3 | 1–4 |
| ⩽10 mm | 10 | 8–14 | 11 | 8–14 |
| 11–20 mm | 41 | 35–48 | 44 | 37–51 |
| 21–50 mm | 34 | 28–41 | 37 | 30–44 |
| ⩾51 mm |
5 |
2–9 |
6 |
2–10 |
|
Steady-state proportion of women with undiagnosed cancer | ||||
| No cancer | 99.4 | 99.1–99.6 | 99.5 | 99.4–99.6 |
| Indolent DCIS | 0.2 | 0.1–0.4 | 0.0 | 0.0–0.1 |
| Aggressive DCIS | 0.0 | 0.0–0.0 | 0.0 | 0.0–0.1 |
| ⩽10 mm | 0.1 | 0.1–0.2 | 0.1 | 0.1–0.2 |
| 11–20 mm | 0.2 | 0.1–0.3 | 0.2 | 0.1–0.3 |
| 21–50 mm | 0.1 | 0.0–0.1 | 0.1 | 0.0–0.1 |
| ⩾51 mm |
0.0 |
0.0–0.0 |
0.0 |
0.0–0.0 |
|
Steady-state proportion of women with undiagnosed cancer (conditional on some cancer) | ||||
| Indolent DCIS | 30 | 12–53 | 10 | 6–16 |
| Aggressive DCIS | 2 | 0–4 | 10 | 6–16 |
| ⩽10 mm | 24 | 15–33 | 30 | 22–39 |
| 11–20 mm | 33 | 21–47 | 44 | 34–56 |
| 21–50 mm | 10 | 5–18 | 14 | 7–23 |
| ⩾51 mm | 1 | 0–2 | 1 | 0–3 |
Abbreviations: CI=confidence interval; DCIS=ductal carcinomas in situ.