A genetic test is an analysis of DNA performed using a sample of your blood, saliva, or tumor tissue.

Two categories of tests

Genetic tests can be divided into two main categories:

• Those that analyze genes inherited from the family.
• Those that study genetic changes present in cancer cells.

The first type looks for a hereditary mutation, also called a germline mutation. These mutations are passed down within families and can increase the risk of developing certain cancers, including prostate cancer. This test is performed using a blood or saliva sample.

The second type of test examines mutations found only in cancer cells, known as somatic mutations. This analysis helps to better understand the tumor’s behavior and assess whether certain targeted treatments might be appropriate. This test is performed using a tumor sample (biopsy) or through a liquid biopsy (which analyzes fragments of circulating tumor DNA in the blood).

What can a genetic test reveal?

When a test detects a germline mutation, it means a genetic change has been present from birth and can be passed down in the family (e.g., BRCA1, BRCA2). This type of mutation is associated with a higher risk of developing certain cancers, such as prostate, breast, or ovarian cancer. This information can therefore be relevant not only for the person tested but also for some family members.

In contrast, a somatic mutation is acquired during a person’s lifetime and is found only in cancer cells. It is not hereditary and does not affect family members. However, its presence can guide the choice of certain targeted treatments, such as PARP inhibitors.

Genetic testing is not recommended for everyone with prostate cancer. However, it may be suggested in certain clinical situations. For example, it can be considered for individuals with advanced or metastatic prostate cancer, or when the cancer shows characteristics indicating a potentially more aggressive behavior.

A genetic test may also be relevant if there is a family history of cancers, including prostate, breast, ovarian, pancreatic, or colorectal cancer, which could suggest the presence of an inherited mutation.

In some cases, genetic testing is done to better guide treatment options, particularly when a targeted therapy might be considered.

The decision to undergo a genetic test is based on a medical evaluation and, if needed, a discussion with your healthcare team. Your doctor may recommend testing if:

• Your cancer is advanced or aggressive
• You have a family history of cancer (prostate, breast, ovarian)
• You were diagnosed at a young age
• Targeted treatments might be applicable

Precision medicine involves tailoring treatment to your genetic profile. It does not replace standard treatments but can complement them.

It may allow you to:

• Receive targeted therapy (e.g., PARP inhibitors)
• Participate in a clinical trial
• Better understand the progression of your disease

Advantages and limitations

Genetic testing can provide valuable information, such as better understanding the risk of certain cancers or guiding treatment options. However, it does not always provide clear or immediate answers. Sometimes no mutation is detected, or the results may not directly impact medical decisions. Results should always be interpreted in a proper medical context, considering the individual’s overall situation.

Advantages:

• More personalized treatment
• Fewer unnecessary side effects
• Access to innovative therapies
• Useful information for family members
• Contribution to research

Limitations:

• Not always a usable mutation
• Not always immediate impact
• Variable cost or access
• Complexity of results
• Possible emotional impact

When a genetic test reveals a hereditary mutation, this information can also be important for certain family members, as it may have implications for their own risk of developing cancer.

Discussing it with your relatives helps promote a better understanding of the risks and, if necessary, consider appropriate monitoring or preventive measures. This important conversation can be sensitive and raise complex emotions or questions. That’s why the support of a healthcare professional, such as your doctor or nurse, can be helpful in facilitating communication and addressing everyone’s concerns.

Helpful questions to ask your doctor:

• Should I consider a genetic test?
• What type of test is relevant for my situation?
• Which genes will be analyzed?
• What could the test reveal?
• How could the results affect my treatment?
• Should my family be informed?
• Is it covered by public healthcare or my insurance?