Thanks to research funded by the Prostate Cancer Foundation, we now know that some prostate cancers are caused by changes in your genes. 5%-10% of all cancers are hereditary, meaning that certain cancer-causing gene changes are passed down from mothers and fathers to sons and daughters. Another 10%-20% of all cancers are “familial,” meaning that a type of cancer occurs in multiple family members, but is not directly related to specific gene changes.
Genes are made of DNA, which is the master “instruction manual” that tells every cell in the body which proteins to make – essentially, the information that each cell needs to do its job. A genetic mutation is a change in part of the normal DNA that makes up a gene. Some mutations are hereditary, meaning that they are passed down from one family member to another. Mutations can also be caused after birth by various lifestyle and environmental factors, such as smoking or the UV rays from the sun.
Genetic mutations can be passed down from father to son, father to daughter, mother to son, or mother to daughter. We now know that some of the same gene mutations that cause prostate cancer can also cause other forms of cancer (such as breast, colon, pancreatic, and others) – and vice versa. Therefore, it can be important to consider genetic testing if you have a history of cancer in your family, even if it’s not prostate cancer. This is referred to as genetic testing for an inherited mutation or genetic testing for inherited cancer risk. (You may also hear it called “germline genetic testing.”)
The testing itself is a simple saliva or blood test. It is important to consult your doctor and/or a genetic counselor to discuss the risks and benefits of genetic testing. Keep in mind that the testing you can order online is not a substitute for clinical genetic testing through a physician or genetics professional.
All patients with prostate cancer who have certain characteristics are now encouraged to speak to their physician about whether they may need genetic testing for an inherited mutation. These characteristics include: high risk, regional, or metastatic prostate cancer, Ashkenazi Jewish ancestry, family history of cancer risk gene mutations (e.g., BRCA1, BRCA2), or a strong family history of prostate or other cancers.
There is another important reason to ask your doctor about genetic testing. If you have advanced prostate cancer, the results of genetic testing may also help guide your treatment. Medications called PARP inhibitors (olaparib and rucaparib) are FDA-approved for patients with metastatic castration-resistant prostate cancer who also have mutations in certain genes that repair damaged DNA.
For more information on the genetics of risk, download PCF’s Prostate Cancer Patient Guide
You may hear about another type of cancer testing called biomarker testing (also referred to as somatic testing or tumor testing). This testing is performed on tumor tissue from biopsy samples or after prostatectomy and looks for several different characteristics of the cancer – including gene mutations that may be inherited or were acquired during disease progression. Read more about biomarker testing here.
Someday, genetic testing may be a first step that any doctor takes in diagnosing and treating many different types of disease. As medicine continues to transition towards precision medicine, be prepared to be your own patient advocate: know your family cancer history, and don’t be shy about asking your doctor if genetic counseling is right for you.
See more information about genetic testing in this video and at the National Society for Genetic Counselors.