Genetic Testing and Gynaecological Cancer

Posted in genetic testing, gynaecological cancer; Posted 3 years ago by Andreas Obermair

If I have been diagnosed with gynaecological cancer, should I or my family members obtain genetic testing?

Some gynaecological cancers can be inherited, or caused by a faulty gene. Below, I describe whether genetic testing should be offered to patients diagnosed with gynaecological cancers – including ovarian, endometrial, cervical, vaginal or vulval cancer.

Ovarian Cancer

All women diagnosed with invasive epithelial ovarian cancer, fallopian tube or primary peritoneal cancer (except women with mucinous ovarian cancer), regardless of their age, family or personal history, should be offered genetic testing. These women may carry a fault (mutation) in BRCA1`, BRCA2 or another gene even if they don’t have or are aware of a family history of ovarian cancer.

Cancer Australia suggests a woman with invasive epithelial ovarian cancer should be offered genetic testing for a heritable mutation in BRCA1 or BRCA2, if she meets any of the following criteria:

• Has high grade (Grade 2 or 3) invasive non-mucinous ovarian cancer, diagnosed at 70 years or younger.
• Has invasive non-mucinous ovarian cancer at any age, with a personal history of breast cancer, or a family history of breast or ovarian cancer.
• Is from a population where a common founder mutation exists, such as the Ashkenazi Jewish population.
• Is assessed as >10% chance of having a BRCA1/2 mutation, using a prediction tool (such as BOADICEA, BRCAPRO or Manchester score).
• Has relapsed platinum-sensitive ovarian cancer, is a candidate for treatment with PARP inhibitors and meets Medicare benefits scheme (MBS) criteria.

For a woman with invasive epithelial ovarian cancer who has a personal or family history of endometrial, colorectal or other cancer suggestive of Lynch syndrome, tumour tissue should be tested for Lynch syndrome abnormalities.

If an abnormality associated with Lynch syndrome is identified in the tumour, genetic testing for a heritable mutation in a DNA mismatch repair gene should be offered.

Genetic testing follows a two-pronged process. First, tissue will be submitted for somatic testing. Secondly, blood or sputum will be submitted for germline testing. Somatic and germline tests determine two different genetic faults. The somatic testing determines faults in the tumour tissue (not inherited, still relevant for ovarian cancer treatment), whereas the germline test determines the presence of genes that can be passed on from the parents to their offspring.

Endometrial Cancer

Only a small percentage (about 5%) of endometrial cancers are due to hereditary factors and most hereditary endometrial cancers are attributed to Lynch syndrome. Patients with Lynch syndrome are younger than usual and often these women are aware of a family history of endometrial, stomach, bowel or kidney cancer.  

In my practice and in collaboration with pathologists I work with, we scan all patients with endometrial cancer, regardless of age, personal or family history for Lynch syndrome. Endometrial cancer tissues of all patients will be examined for Lynch.

If the tissue test shows an abnormal finding (suspicious for Lynch), patients will require a blood test to confirm Lynch.

Cervical Cancer

Typically cervical cancers are not hereditary, but are caused by an infection with the Human Papilloma Virus (HPV). There is little evidence that cervical cancer is related to a genetic predisposition. Rather, certain faulty genes make it more challenging for the body to fight off the HPV infection. Sometimes it appears that members of the same family have cervical cancers more often. In such cases it is commonly that women share the same risk factors (e.g., cigarette smoking) that then can increase one’s risk of cervical cancer.

While it’s not clear if a cervical cancer diagnosis was caused by genetic or non-genetic factors, regular HPV screening tests can accurately determine your risk, rather than genetic testing.

Vaginal and vulvar cancer

These cancers are the rarest type of gynaecological cancers. Some cases of vaginal and vulvar cancer do not have a clear cause, but most are linked to the HPV infection or a chronic skin condition, called Lichen sclerosus.

There are no gene mutations associated with hereditary forms of vaginal cancer. Although, an inherited condition called Fanconi anaemia is associated with an increased risk for vulvar cancer. Fanconi anaemia is an inherited bone marrow failure syndrome. This condition is very rare and may cause only a small proportion of all vulvar cancers.  There is also some evidence that a small number of vulvar cancers may be related to a genetic predisposition, but the specific gene is not yet known.

Overall, I don’t recommend genetic testing for vaginal or vulvar cancer.

What does genetic testing involve?

Genetic testing involves a tissue, blood or saliva test. Genetic counselling will involve discussing the possible outcomes and implications of genetic testing. The choice to proceed with genetic testing after meeting with a genetic counsellor is entirely up to the patient.

Family members

It is always important to test the affected cancer patient (the index family member, the “index case”) first. If a faulty gene associated with a higher risk of cancer is found, a genetic counsellor will suggest offering genetic testing to other immediate family members.

Insurance

Some patients mention they are worried about the impact genetic test results will have on their health insurance policies. Genetic testing will not affect health insurance policies. However, life insurance and similar products (e.g., business insurance) may be impacted by genetic testing. For more information about life insurance and genetic testing in Australia. Read the factsheet here.

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