Certain types of cancer are hereditary, meaning they can be passed down through families. Genetic testing is a way of identifying people at increased risk of these hereditary cancers, but it has tended to be women rather than men who, historically, have been encouraged to get themselves tested.
However, growing evidence suggests that men as well as women would benefit from testing for genetic mutations that increase the risk of cancer.
To mark Breast Cancer Awareness Month 2019 (1 October – 31 October), we are looking at why this is and how genetic testing works.
BRCA1 and BRCA2 genetic mutations
One of the most common tests is for the BRCA1 and BRCA2 gene variant, which greatly increases the risk of breast and ovarian cancers in women.
High profile cases of women like Angelina Jolie who underwent preventative breast cancer surgery after discovering she had the BRCA gene variant have helped to increase awareness of BRCA1 and BRCA2, but less well-known is the fact that men as well as women can be affected.
Men carrying BRCA1 or BRCA2 gene mutations are at risk of breast, pancreatic or prostate cancer, as well as melanomas.
Scientists call for more testing
A recent article in Nature, the international journal of science, called for national and international guidelines on BRCA testing to be extended to include men with a family history of prostate or pancreatic cancers.
The UK’s National Institute for Health and Care Excellence and the European Society for Medical Oncology were both cited in the article, which pointed out that just 357 men had been tested for BRCA1 and BRCA2 at the European Institute of Oncology since 2001 compared to 4,728 women.
Seventy-three of these men were “probands”, which means they were the first in their family to test positively for these genetic mutations. The remaining 284 had blood relatives with genetic mutations.
Forty per cent of men with prostate cancer had a BRCA mutation.
The overall ratio of women to men having genetic testing is 13 to one. Increasing the number of men being tested would help to improve early diagnosis of those at risk of hereditary cancer and improve the diagnosis, treatment and options to participate in clinical trials.
What are BRCA mutations?
Certain genes normally work to protect the body from cancer. However, some people inherit a mutation, or change, in one of these protective genes, known as a BRCA1 and BRCA2 mutation. When this happens, there is a significantly increased risk of cancer. For women, the risk is of breast or ovarian cancer, while for men it is breast, prostate and other cancers.
Having the gene mutation doesn’t necessarily mean you will get cancer but it does mean that you are at a significantly higher risk than someone without the genetic mutation. It also means your children have a 50% chance of carrying the same genetic mutation and an associated increased cancer risk.
Genetic testing for cancer – who should have it?
Genetic testing for cancer provides a way of finding out if you carry the BRCA genetic mutation.
It is normally recommended that women are tested if they have a family member with:
- Breast cancer below the age of 50.
- Ovarian or fallopian tube cancer.
- Breast cancer more than once.
- Eastern European (Ashkenazi) Jewish ancestry.
- Triple negative breast cancer.
For men, it is recommended that you are tested if:
- You have metastatic or advanced prostate cancer and a family history of the disease.
- You have a strong family history of breast, ovarian or prostate cancer.
- Any of the breast cancers occurred before age 50 (in either female or male relatives).
- You have a family member with a known BRCA mutation.
- You have three or more relatives with pancreatic cancer on the same side of the family (familial pancreatic cancer).
- Two or more first-degree relatives (parent, brother, sister or child) have pancreatic cancer.
- Relatives were diagnosed with pancreatic cancer under the age of 60.
This list includes some of the more common scenarios. Any family history that is of concern, speak with your GP or a specialist so they can advise if genetic testing would help outline your personal risk.
Genetic testing – how it works
Genetic testing uses a simple saliva test to identify your risk for 25 types of hereditary cancer, by analysing 98 genes from your DNA. There is also a specific BRCA cancer test, which tests for BRCA1 & BRCA2 as well as a number of related genes.
The sample is sent off to the laboratory for testing and your doctor will receive a detailed test report, including a personalised health risk management plan.
If you are identified as being at increased risk, a clinician can discuss with you how to take proactive steps to manage your health, including having regular screening or, in some cases, preventative medication or surgery.
You may also wish to recommend testing to other close family members who may be at increased risk.