Familial ovarian cancer

Ovarian cancer is less common than breast cancer, with a lifetime risk of 1%.

Consequently, a family history of ovarian cancer is less likely to occur by chance than with breast cancer.

Approximately 5% of ovarian cancer is due to a dominantly inherited gene. This is usually BRCA1 or BRCA2. 

There are rarer genetic cancer syndromes which can present with breast and ovarian cancer, for example Peutz Jeghers syndrome. Ovarian cancer can also be a feature of Lynch syndrome (HNPCC).

There is an association between breast and ovarian cancer, with the autosomal dominant BRCA1 and BRCA2 genes predisposing an individual to both a high risk of developing breast and ovarian cancer (and prostate cancer in BRCA2).

An autosomal dominant pattern of inheritance means that a patient need only inherit one copy of a faulty gene to be at risk. This faulty gene may not always cause disease within an individual (penetrance) but could still be passed on to future generations. 

The penetrance of BRCA genes is much lower in men but they can still pass on the gene to their offspring. Therefore, when considering a family history in the case of breast and ovarian cancer, it is important not to overlook the paternal family history.

In some families, there may only be cases of ovarian cancer reflecting an underlying genetic predisposition.

There are specific populations which have an increased risk of developing BRCA1 and BRCA2 related breast cancers, for example the Ashkenazi Jewish population.

Discussing risk with your patient and management of moderate and high risk patients

Using the Familial Ovarian Cancer Referral Guidelines it should be possible in most cases to determine whether your patient is at population (low) risk and can be managed in Primary Care, or whether your patient’s risk may be raised, and they would therefore benefit from referral. 

It may be helpful to consider what you might want to say to your patients in each of these situations and discuss with them possible future management.