Ovarian cancer is a relatively uncommon cancer affecting approximately about 1 in 80 women in their lifetime. The majority of ovarian cancer, 90-95%, occurs by chance. Only a small proportion of the disease, approximately 5-10%, is thought to occur due to an inherited strong predisposition.
An inherited predisposition means that there is a gene fault which can be passed through the family from one generation to the next. The small proportion of ovarian cancer that is inherited may be linked to faults in the Breast Cancer 1 (BRCA1) gene or the Breast Cancer 2 (BRCA2) gene. There will be other genes linked to ovarian cancer which have yet to be identified.
BRCA1 and BRCA2 gene faults account for about 5% of ovarian cancers among women under 70. It is thought that individuals with a BRCA1 gene fault may have up to an 50% lifetime risk of ovarian cancer, whereas individuals with a BRCA2 gene fault have a 10-20% lifetime risk of ovarian cancer.
At present there is no routine screening programme for women with a family history of ovarian cancer as we do not know whether it is effective or indeed possible. For women who are at significant risk, preventive surgery (removal of ovaries and fallopian tubes) may be offered.