Objective: To estimate the relative risk and lifetime risk of ovarian cancer in women with various categories of family history.
Design: A meta-analysis of all published case-control and cohort studies.
Methods: Pooled relative risk estimates were calculated for the case control studies, using the Mantel-Haenzel method. These estimates were combined with the relative risks from the cohort studies. The pooled estimates of relative risk were used to estimate lifetime risks of ovarian cancer from age 15 up to age 75, for various categories of family history.
Main outcome measures: Relative risks and lifetime risks of developing ovarian cancer were calculated for the categories of women with 1. an affected first degree relative; 2. an affected mother; 3. an affected sister; and 4. women with more than one affected relative.
Results: The relative risk to first degree relatives is 3.1 (95% CI 2.6-3.7). There is some evidence that this relative risk declines with age. The relative risk to mothers of cases 1.1 (95% CI 0.8-1.6) was lower than the relative risks to sisters: 3.8 (95% CI 2.9-5.1), and daughters: 6.0 (95% CI 3.0-11.9); the explanation of this difference is unclear.
Conclusions: Women with a family history of ovarian cancer have a substantially higher risk of developing ovarian cancer compared with women without such a history. However the risk is small for most categories of family history, except for the small number of individuals who have more than one affected relative.