Risk-reducing surgery to prevent ovarian cancer involves removal of tubes and ovaries. This has traditionally been performed in women at high risk (>1-in-10 chance) of getting ovarian cancer (e.g. BRCA1/BRCA2 carriers). However, the ovarian cancer risk level at which surgical prevention should be offered has not been previously defined. We undertook a health economic analysis comparing surgical prevention with no surgery at different ovarian cancer risk levels of 2%, 4%, 5%, 6%, 8% and 10% in pre-menopausal women >40 years. We found that surgical prevention is highly cost-effective in women at the ≥4% lifetime risk of ovarian cancer, leading to increased life-expectancy for an incremental cost-effectiveness ratio =£19536/QALY. Current surgical prevention guidelines should be re-evaluated to reduce the ovarian cancer risk threshold to benefit a number of at-risk women who presently cannot access risk-reducing surgery. (By Dr Ranjit Manchanda, http://jmg.bmj.com/content/early/2016/06/06/jmedgenet-2016-103800 )