Do I Need Genetic Testing for Prostate Cancer?

Perhaps you’ve just been diagnosed with prostate cancer, or you’re waiting for your tumor biopsy or scan results, and you’re wondering if genetic testing would help your case. Maybe you feel completely fine, but a relative has just received a worrying result on a cancer gene test, and you don’t know the next step to take.

Whether you should undergo genetic testing for prostate cancer will largely be dependent on your personal and family history of cancer or cancer susceptibility gene mutations, as well as your reasons for testing.

For healthy people, it is unlikely that you will be the first in your family to need genetic testing for prostate cancer. A typical scenario may be that you’ve been asked to consider genetic testing after a female relative has been found to carry a BRCA1 or BRCA2 mutation. In this case, a genetic test could help inform your future risk of prostate cancer, as well as your children’s risk of carrying this cancer susceptibility gene mutation. This is especially so as such genes may indicate a higher risk of breast or ovarian cancers for your daughter.

According to the US National Comprehensive Cancer Network (NCCN) guidelines, if you currently do not have prostate cancer, germline testing is only recommended if you have:

• Family history of a known or suspected mutation in a prostate cancer susceptibility gene
• Family history of hereditary prostate cancer, breast cancer, ovarian cancer, or colon cancer syndromes
• Ashkenazi Jewish ancestry
• Prior history of Lynch syndrome (risk should be considered based on the Lynch syndrome gene and your family history of prostate cancer)

On the other hand, if you have been diagnosed with localized prostate cancer (e.g. Stage I or II), testing is only needed when it is likely to impact your treatment, clinical trial options, risk management of other cancers or to determine potential risk for your family. Germline testing is then recommended by the NCCN if you have:

• Family history of known or suspected mutation in a prostate cancer susceptibility gene
• Prior history of prostate cancer AND
  • Faced prostate cancer with intermediate risk and intraductal or cribriform histology
  • Personal history of cancers including exocrine pancreatic, upper tract urothelial, glioblastoma, biliary tract & small intestinal
  • Strong family history of cancers including prostate, breast, colorectal, endometrial, ovarian, exocrine pancreatic and other Lynch-syndrome related cancers.
  • Ashkenazi Jewish ancestry
• Prior history of male breast cancer

Finally, if you have been diagnosed with locally advanced or metastatic prostate cancer (e.g. Stage III or IV), germline testing is recommended regardless of your family history. Somatic testing is also recommended for those with metastatic prostate cancer. Genetic testing holds a particularly strong relevance at this end of the disease spectrum. While possibly invasive, such a test will help to broaden your alternative personalized treatment options (e.g. olaparib).

Genetic testing is now a routine consideration in managing and predicting prostate cancer risk and treatments. Taking on a test like this may help advise your care team on the best preventative measures to take. It can also help to advise if your family is at risk for certain cancers and pinpoint personalized therapies or clinical trials that may be appropriate for you.

However, it is good to remember that genetic testing is not always the best answer, especially for low-risk prostate cancer. As the primary focus of treatment at this stage is typically active surveillance, genetic testing may not affect your treatment plan at all.