How can somatic and germline genetic testing help me?
Treatment selection
Somatic and germline genetic testing have several important benefits. The first is treatment selection. Treatment selection is important because advanced prostate cancer is different for everyone. This means that a treatment that works well for one person might not help another. Somatic and germline genetic testing can help show you and your doctor which treatment is most likely to work for you.
For example, treatments called PARP inhibitors work best if you have gene alteration(s) affecting DNA repair. In contrast, immunotherapy may work well if your tumor cells have changes called microsatellite instability (MSI-H), mismatch repair deficiency (dMMR), or high tumor mutational burden (TMB-H).
Only some of the important gene alterations in prostate cancer are found through somatic testing. The rest are found through germline genetic testing. Therefore, getting both types of tests will provide the most complete understanding of your treatment options.
Other benefits
These tests also can help you understand your prognosis, and whether you are eligible for clinical trials of new therapies. In addition, germline genetic testing can help you and your family find out if you are at increased risk for certain cancers. This can help everyone make informed choices to support the best possible health outcomes.
At what point during treatment should I be tested?
The tables below show somatic testing recommendations and germline genetic testing recommendations for different situations.
| Situation | Is Somatic Testing Recommended? |
|---|---|
| Advanced prostate cancer (has spread to other places in the body like the bones, lungs, or liver) | Yes |
| Node-positive prostate cancer (has spread from the prostate gland to nearby lymph nodes, but not to other places in the body) | Consider—talk with your doctor |
| Advanced prostate cancer that has progressed on treatment | Consider repeat testing* |
| A new treatment or test is available | Consider repeat testing |
| Localized prostate cancer (is confined to the prostate gland) | Not usually (you may wish to ask your doctor) |
*Tumor genes can change (mutate) in response to treatment, which can affect the next treatment choice. This is why repeat somatic testing is considered if your cancer has progressed on a treatment.
| Situation | Is Germline Genetic Testing Recommended? |
|---|---|
| Advanced prostate cancer | Yes |
| Node-positive prostate cancer | Yes |
| Very high-risk or high-risk localized prostate cancer | Yes |
| At least one first or second-degree relative with: advanced, node-positive, or high-risk/very high-risk prostate cancer, female breast cancer (at or before age 50), male breast cancer (any age), pancreatic cancer, or ovarian cancer | Yes |
| At least two close blood relatives with prostate cancer or breast cancer on the same side of the family | Yes |
| Prostate cancer and Ashkenazi Jewish ancestry | Yes |
| Diagnosed at age 55 or younger | Consider (talk to your doctor) |
| Intermediate risk and intraductal/cribriform histology | Consider (talk to your doctor) |
Should I wait for my results to start a new treatment?
It can take a few weeks to get your test results. Waiting to start a new treatment can feel stressful, but it helps make sure you get the most effective and personalized care, which may improve your long-term outcomes. Talk with your doctor to see if a short delay makes sense for your specific situation and to address any concerns about about waiting for your test results.
Experts recommend getting both somatic and germline genetic testing as soon as advanced prostate cancer is diagnosed. Getting both tests will give you and your doctor the most complete understanding of your treatment options.