Probabilities of pathways in the model
| Probability | Value | (CI) [range] | Description | Source |
|---|---|---|---|---|
| p1 | 0.1, 0.08, 0.06, 0.05, 0.04, 0.02 | ‘Lifetime risk’ of developing ovarian cancer | Model assumption | |
| p2 | 0.94 | [0.83–0.98] | Reduction in ovarian cancer risk from RRSO | Parker7 |
| p3 | 0.13 | [0.065 to 0.195] | ‘Lifetime risk’ of developing breast cancer | CRUK21 |
| p4 | 0.38 | (0.26 to 0.47) | Reduction in risk of breast cancer from RRSO alone | Parker68 |
| p5 | 0.03 | (0.011 to 0.046) | Risk of fatal CHD after RRSO and no HRT | Parker7 |
| p6 | 0.80 | [0.76–0.83] | Compliance with HRT | Read23 |
Explanation for probabilities.
p1: These are the different lifetime risks of developing ovarian cancer. The model was run and analyses undertaken at these different risk thresholds.
p2: The level of reduction in ovarian cancer risk following RRSO is obtained from the Nurses Health Study.7
p3: Lifetime risk of developing breast cancer 12.9% from CRUK.21 This was varied in the sensitivity analysis by ±50% to better reflect the distribution of risks in the population.
p4: The reduction in breast cancer risk in premenopausal women undergoing RRSO is taken from Parker et al.68
p5: Risk of a fatal CHD event is 1/33 for women undergoing RRSO and do not take HRT.7 This is not seen in women who do take HRT.7.
p6: Compliance with HRT is obtained from a UK cohort of 512 women.23
CHD, coronary heart disease; CRUK, Cancer Research UK; HRT, hormone replacement therapy; RRSO, risk-reducing salpingo-oophorectomy.