This page is not intended as patient information. For information about hereditary ovarian cancer, read this page.
Greater understanding of a family history of ovarian cancer is crucial for GPs.
Women with a history of ovarian and breast cancer in their family need support in making risk reduction decisions, and in checking for symptoms to ensure early diagnosis for those at high risk of the disease.
If a woman with a family history of ovarian or breast cancer is diagnosed, they may need GP support in identifying or telling other family members at risk. Some genetic mutations can also impact how a woman responds to treatments.
Up to 20 per cent of women diagnosed with ovarian cancer will have an inherited form of ovarian cancer, for example BRCA1 or 2 gene mutations. The average woman has a two per cent chance of developing ovarian cancer at some point during her lifetime. This increases to between 15 and 45 per cent if she has a mutation in either the BRCA1 or 2 genes.
Resources for GPs
- Target Ovarian Cancer’s position statement on familial ovarian cancer provides all health professionals and policy makers with detailed information on the challenges facing women with a family history of ovarian and/or breast cancer.
Key questions on ovarian and breast cancer genetics
1. When clarifying a family history, what areas should the GP explore? How important is the father’s side of the family when reviewing the genetic link of cancer?
- Has anyone on either side of your family had breast and/or ovarian cancer?
- Has anyone been diagnosed with breast cancer under 50 years and/or ovarian cancer at any age?
- How big is your family? How many men vs. women in the family?
- Is there any Ashkenazi Jewish ancestry (where appropriate)?
With these four questions it should be possible to make a rapid assessment and determine whether a more detailed investigation is required. It is crucial to ask about the paternal side and actively seek this information out. All the main cancer susceptibility genes can be passed on by either sex, but because men rarely get breast cancer and of course never get ovarian cancer the family history can appear more distant on the male side.
BRCA1/BRCA2 mutations are ten times more common in individuals of Ashkenazi Jewish descent so it is important to ask about this where appropriate.
2. What is the genetic link between breast and ovarian cancer? How often is there a genetic component in these diseases?
There is a strong hereditary link between breast and ovarian cancer. By far the two most important genes causing breast and ovarian cancer are BRCA1 and BRCA2, both discovered in the mid-1990s. These account for around 85 per cent of hereditary breast and ovarian cancer families (Robson and Offit 2007). Despite extensive research over the last 20 years, no other genes of similar importance have been identified.
There are some other genes that have been linked to ovarian cancer such as RAD51C and RAD51D, and those linked to Lynch Syndrome (also known as hereditary non-polyposis colorectal cancer, HNPCC), which mainly predisposes to colorectal and endometrial cancer, but also ovarian cancer. A larger proportion of currently unexplained breast cancer families may be due to particular combinations of weaker-acting genes (polygenic inheritance).
3. How will a woman at high risk of ovarian cancer be managed? What is the role of the GP in this situation?
There are currently no convincing data that surveillance using CA125 and/or pelvic ultrasound reduces mortality in women at high risk and it is not routinely recommended outside of clinical trials (Rosenthal et al. 2013). Instead, for BRCA1/BRCA2 mutation carriers risk-reducing bilateral salpingo-oophorectomy (RRBSO) once the woman has completed her family is recommended. The exact timing of this, and desire to undergo such a procedure varies from one person to the next and requires a detailed discussion with a gynaecological oncologist who has expertise in preventative surgery.
GPs should make women aware of symptoms of ovarian cancer, and explain to their patients that the benefits of surveillance for ovarian cancer are unproven.
- In cases where a patient presents with concerns of familial ovarian cancer a first and second degree family history should be taken to assess individual risk
- If an individual is considered ‘at risk’ they should be referred to your local clinical genetics service for further assessment. If you are unsure if your patient is at risk contact your local genetics centre for advice before making a referral
- Men are often offered testing in the pre-symptomatic setting, for example if a man comes from a family with a known gene mutation and is worried about whether his daughters may be at risk.
- If a women has a serous-papillary type (the commonest type) then her specialist centre may offer BRCA1/BRCA2 testing if she was under 60, even if she did not have any other significant family history. This is because it is now known that around 13-18 per cent of women with a serous-papillary type of ovarian cancer will have a mutated BRCA1 or BRCA2 gene (most centres use a 10 per cent threshold i.e. there must be more than a 10 per cent chance of finding a mutation before genetic testing is offered).
- Men are sometimes offered diagnostic testing if they are affected with male breast cancer, early onset pancreatic or prostate cancer (all associated with BRCA2 mutations).
There is currently no NICE guidance on familial ovarian cancer. The information in this section is based on NICE guidance for familial breast cancer, SIGN guidelines for epithelial ovarian cancer and relevant references.