What’s the Impact of Updated Prostate Cancer Genetic Testing Recommendations?
The National Comprehensive Cancer Network (NCCN) issued updated prostate cancer guidelines that include new information about the role of genetic testing for those with prostate cancer1. These updates expand the criteria to include more people with prostate cancer or people with family histories of prostate cancer who may be eligible for and benefit from genetic testing.
The NCCN now recommends consideration of genetic testing for the following1:
- All men with high-risk, very high-risk, regional, or metastatic prostate cancer.
- All men with any stage prostate cancer and a family history consisting of one (or more) of the following:
- Brother, father or multiple family members diagnosed with prostate cancer at <60 years of age.
- Family member with a known genetic mutation.
- More than one relative with breast, ovarian or pancreatic cancer.
- More than one relative with colorectal, endometrial, gastric, ovarian, pancreatic, small bowel, urothelial, kidney or bile duct cancer.
Genetic testing can help identify people or families who have hereditary cancer. Hereditary or inherited cancer occurs when a person inherits a mutated or non-working cancer susceptibility gene from one of their parents. A gene is a coded message inside a cell that tells it how to behave. Genes control how our bodies grow and develop. Cancer susceptibility genes are supposed to protect our cells from getting cancer by repairing damaged DNA. If one of these cancer susceptibility genes is mutated that person is at increased risk to develop cancer compared to others whose cancer susceptibility genes are working correctly. It is thought that 5-10 percent of those with prostate cancer carry a gene mutation that puts them at increased risk for prostate cancer and/or other cancers. Inherited forms of prostate cancer tend to be more aggressive, develop at a younger age, and seemingly “run through the family”.
Not every person with aggressive prostate cancer or a family history of cancer will have a genetic mutation. In most people, the underlying cause of a person’s cancer is unknown. We call this sporadic cancer, meaning that chance events occurred resulting in cancer but there was no underlying predisposing gene mutation. It is estimated that about 90 percent of men have sporadic cancer.
An example of a gene mutation that can increase the risk of prostate cancer is in the BRCA2 gene. This mutation can increase a man’s lifetime risk of getting prostate cancer to about 20 percent2. Additionally, mutations in this gene can cause increased risks for female and male breast cancers, ovarian cancer and pancreatic cancer. Mutations in MLH1, MSH2, MSH6, or PMS2, also called the Lynch syndrome genes, can increase a man’s chance of getting prostate cancer nearly 5-fold3. Mutations in these four genes also increase a person’s risk for colorectal, endometrial and ovarian cancers.
If a person carries a mutated cancer susceptibility gene, there is a 50 percent chance that their children, siblings and parents could carry this mutation too. By providing early screening and risk reduction strategies to family members with the same mutation, we may be able to decrease the risk that cancer will develop. Carrying a mutated cancer susceptibility gene does not mean that a person has or that they will get cancer. However, being aware that a person may be at risk for multiple types of cancer allows for early screening.
Genetic testing isn’t right for everyone. For some, knowing they have a genetic predisposition to prostate cancer might mean that they monitor their health more closely. Others might needlessly worry and never get cancer. Some may find that proactive testing gives them the knowledge to discover cancer early and make treatment decisions. It’s a very personal decision that should be discussed with your physician.
1National Comprehensive Cancer Network. Prostate Cancer (4.2018). https://www.nccn.org/professionals/physician_gls/pdf/prostate.pdf. Accessed 1/12/2019.
2Nielsen, R., Petersen, J., Therkildsen, C., Skytte, A., & Nilbert, M. Increased risk of male cancer and identification of a potential prostate cancer cluster region in BRCA2. Acta Oncologica 2016:55(1):38-44.
3Haraldsdottir, S., Hampel, H., Wei, L. et al. Prostate Cancer incidence in males with Lynch syndrome. Genetics in Medicine 2014:16:553-557.