If your doctor has recommended tumor testing, you might be wondering: What is it? When should I get it? How do I get it? How will my doctor use the information?
What is tumor testing?
Tumor testing is also called biomarker testing. It refers to different types of tests that your doctor can use to gain more insight into the causes of your cancer and your subsequent treatment plan—beyond PSA level, Gleason score, and imaging. The tests examine the tumor’s genetic material or proteins (the “biomarkers”).
Different sources of tissue can be tested: a prostate biopsy sample, the prostate that has been surgically removed, or a metastatic lesion. Tumors shed cells and genetic material into the bloodstream, so, in some cases, a blood sample (known as a “liquid biopsy”) is used.
You may hear many other terms to describe this type of testing, such as molecular testing, genomic testing, tumor sequencing, somatic testing, or genetic testing. While there are some nuances in how the tests are performed and what they are used for, the overall goal is to provide you and your doctor with more information about your specific type of prostate cancer.
When should I have tumor testing?
Tumor testing may be useful at various points in the prostate cancer journey. It can be used for men with localized prostate cancer who are considering their treatment options, post-prostatectomy, or in cases of advanced prostate cancer. Talk to your doctor about whether it may help guide your treatment.
How do I get tumor testing?
If your doctor has ordered tumor testing, it can often be done on existing tissue from a biopsy or prostatectomy. If you have metastases—for example, in the bone—you may need a procedure to collect a sample of tissue. The genes and proteins in metastatic lesions can be different from the original tumor.
How will my doctor use the information?
Below are some examples of how tumor testing/biomarker testing can be used in different situations.
Localized prostate cancer: If you have been diagnosed with localized prostate cancer, tests such as Decipher Prostate Biopsy,® Opko 4K,® Oncotype DX Prostate®, Prolaris®, and ArteraAI Prostate Test® may help provide further assessment of the aggressiveness of your cancer. Read more about these tests from PCF-funded investigator Dr. Himisha Beltran here.
Post-prostatectomy: If you have had surgery to remove your prostate, the Decipher® test may help guide use and timing of additional radiation and hormone therapy.
Advanced prostate cancer: If you have advanced prostate cancer, biomarker tests can potentially identify a precision medicine for your cancer. In some cases, the results may signal that certain therapies are less likely to be effective, and alternatives should be considered.
This table lists some examples of biomarker tests, and how the results might guide treatment.
| Biomarker Test Result | Possible Treatment |
|---|---|
| Mutations in certain DNA damage repair genes |
Treatment with a PARP inhibitor |
| AR-V7 gene expression | Tumor is less likely to respond to hormone therapy; consider other options |
| Mutations in MMR genes, microsatellite instability (MSI) or high tumor mutational burden (TMB) |
Treatment with pembrolizumab |
If you are considering enrolling in a clinical trial, biomarker testing may help determine your eligibility for some trials.
For some patients, biomarker testing may not offer a conclusive answer. Research is still ongoing to understand these complex patterns. It’s also important to live a healthy lifestyle before, during, and after prostate cancer treatment.
Many other biomarkers and targeted treatments are active areas of research funded by PCF. It is the hope that someday, all treatments will be administered with precision, based on results of your biomarker tests.
For more information on the latest cutting-edge treatments, download or order a print copy of the Prostate Cancer Patient Guide.
If you believe biomarker testing may be right for you, the first step is always to talk to your doctor.