Table 1

Probabilities of pathways in the model

ProbabilityValue(CI) [range]DescriptionSource
p10.1, 0.08, 0.06, 0.05, 0.04, 0.02‘Lifetime risk’ of developing ovarian cancerModel assumption
p20.94[0.83–0.98]Reduction in ovarian cancer risk from RRSOParker7
p30.13[0.065 to 0.195]‘Lifetime risk’ of developing breast cancerCRUK21
p40.38(0.26 to 0.47)Reduction in risk of breast cancer from RRSO aloneParker68
p50.03(0.011 to 0.046)Risk of fatal CHD after RRSO and no HRTParker7
p60.80[0.76–0.83]Compliance with HRTRead23
  • 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.