What To Ask Your Doctor About Molecular Testing
- Molecular testing is increasingly used to help create better treatment plans for people with cancer.
- Molecular testing using next-generation sequencing can provide you and your doctor with a more comprehensive genetic profile of cancer.
- The results help identify if you are more likely to benefit from targeted therapy than traditional chemotherapy.
- Molecular testing can open the door for personalized, targeted, and informed care for your cancer treatment.
If you are going to meet with an oncologist as part of your treatment plan for your cancer, there are certain things you want to be sure of before starting the treatment process. Let’s talk about molecular testing and the role it plays in your treatment.
Understanding Molecular Testing
Read MoreWhat is Next-Generation Sequencing?
Next-generation sequencing (NGS) is also commonly referred to as molecular testing. It can be a bit puzzling to hear phrases like molecular profiling, comprehensive genomic profiling, broad molecular profiling, or high-throughput sequencing. But these are all basically the same thing. In clinical practice, many physicians refer to any of these tests as molecular testing so do not be surprised if you hear different terms used during your clinical journey.“NGS is a technique that’s used within molecular profiling. So, it’s really one of the more common things that we use in molecular testing and cancer” says Dr. Hannah McManus, genitourinary medical oncologist at Duke University.
“This genetic testing lets us sequence the DNA or look at the building blocks of the DNA or sequence in a really fast and efficient way to be able to profile someone’s cancer.”
How Molecular Testing Guides Treatment
Molecular testing should be part of discussions between you and your healthcare team.
By looking at the results of the molecular testing, your doctor will get a better idea of:
- Your treatment options & whether you’re likely to benefit from a targeted agent
- Whether the targeted agent is likely to make you live longer, with better quality of life
- Whether your cancer will likely become resistant to a targeted therapy.
- If there are clinical trials that may be right for you
“Molecular testing of the tumor tissue may help us to identify treatment targets and essentially identify targeted therapies for our patients,” says Dr. Katherine Tkaczuk, breast medical oncologist at the University of Maryland Greenebaum Comprehensive Cancer Center.
Newer Targeted Agents Made Possible Using Molecular Testing
Targeted therapy has made the biggest impact on cancer treatment by identifying specific markers that directly target what is causing the tumor to grow. By doing so, they can reduce side effects while increasing the chances of a successful long-lasting response.
In addition, some of the targeted agents also work better than chemotherapy if cancer has spread in the brain.
Dr. Jared Weiss, section Chief of Thoracic and Head/Neck Oncology at UNC Lineberger Comprehensive Cancer Center explains the benefit of targeted agents: “Chemotherapies aren’t reliable in the brain, the new ones (targeted agents) control cancer in the brain beautifully, both to prevent the suffering that comes from cancer in the brain and the suffering that can come, for example, from whole brain radiotherapy.”
Questions To Ask Your Doctor about Molecular Testing
Now that you’re armed with a solid understanding of molecular testing, here are the top questions to ask your doctor about this sort of testing and how it may be helpful for your individual disease.
Is Molecular Testing Common for My Type of Cancer?
Depending on the type and stage of your cancer, the broader molecular testing or NGS test may be helpful in planning treatment for advanced, recurrent, or difficult-to-treat cancers.
NGS testing is typically done with patients diagnosed with the following cancers and others:
- Breast
- Lung
- Colon
- Prostate
In addition, NGS is frequently done on melanoma, thyroid cancer, and cholangiocarcinoma since some of the mutations can be targeted with an already-approved therapy. There are different brands of tests, including OmniSeq Insight and FoundationOne CDx. Certain brands look for different variations or tumor mutations and changes. Be sure to ask your healthcare team if the brand of test you are receiving looks for tumor changes specific to your cancer type.
2. How Will Molecular Testing Be Done?
The first step is to have a discussion with your doctor if your cancer needs molecular testing. Your doctor should walk you through whether it is right for you at your stage of cancer.
If your doctor feels it is appropriate, a molecular test order will be placed. It’s like a test, like an ultrasound that someone does, not a prescription.
The NGS test uses a sample of your tumor (removed during a biopsy or surgery) to look for genetic mutations. This is the gold standard technique. Most recently, there is a newer method called “liquid biopsy” in which the test is carried out on the blood sample to find those mutations. However, in most instances it is preferred to test a tissue sample from a biopsy over a blood sample.
The result of the testing will determine whether your cancer cell has any mutation that may be linked to targeted therapies.
3. How Long Do I Have to Wait to Get the Results?
The results of NGS testing are available within two to three weeks from the date the tumor sample is received by the laboratory.
The results are sent to your doctor so that they can discuss how they may guide your treatment.
4. What are the Pros and Cons of Liquid Biopsy?
A liquid biopsy that analyzes the blood sample is much faster and typically arrives within a week. However, in some cases, there may be a false negative result, which means the test simply failed to find the mutation.
That’s why your doctor may ask for a blood sample to run liquid biopsies as an additional test to a tumor tissue sample, especially when the tumor cell is not sufficient for testing.
5. Will You Run This Test in the Blood and Tissue Samples?
The test results from the liquid biopsy come back faster than the tissue biopsy. That’s why your doctor may send both the tissue-based NGS and a liquid biopsy simultaneously to find if the cancer is actionable and if so, to find it sooner.
6. Will This Test Qualify Me for Immunotherapy?
If you’ve been diagnosed with cancer, both the molecular testing and the PD-L1 test can help you and your doctor make a more informed decision about whether you will benefit from immunotherapy versus targeted therapy.
“Increased levels of PD-L1 in cancer cells may indicate a higher probability of response to cancer immunotherapy. As such, PD-L1 testing is part of molecular profiling when immunotherapy is considered,” Dr. Anagnastou explained.
This means that your doctor will likely consider an immunotherapy drug as a first-line treatment if you have high levels of PD-L1 and no other mutation is found in the molecular testing with an approved targeted agent.
7. Will This Test Qualify Me for a Clinical Trial?
Molecular testing may help guide your eligibility for a clinical trial. The reports usually have information about your genes, and the abnormalities (mutation), and most of the time there’s additional information about the possibility of a clinical trial and where the trial is located.
“Most of the clinical trials that are driven by specific molecular alterations will require this type of testing. says Dr. Katherine Tkaczuk. “I think it is extremely important to continue to support the clinical trials that look at a targeted agent to a mutation that is relatively rare, where not that many patients will be able to be eligible for that particular trial.”
8. How Can I Advocate for Myself in Cancer Treatment?
It is very important to discuss your options with your healthcare provider to know what’s best for your condition.
“These questions should be posed from the get-go, even if the physician may not fully discuss them, but the patient should ask the following questions. What are my options in terms of molecular testing? When the results come, what does this really mean? What is the evidence behind all of this?” Dr. Anagnastou suggests.
9. Will Testing Help in Early-Stage Cancer?
NGS is currently the standard of care for many advanced-stage cancers. However, in some instances, this testing may be useful even if the cancer is in an early stage. These include:
- Lung cancer: Molecular testing can benefit non-squamous non-small cell lung cancer patients even in earlier stages of cancer. Now we have FDA approval for targeted therapies in the adjuvant,or follow-up, setting. So, because of the availability of these drugs patients are often sent for molecular and genetic testing, says UNC’s Dr Weiss.
- Colon cancer: Molecular testing can be performed in all colon cancer patients. “Molecular profiling is an important test for all stages of cancer. In early-stage colon cancer, it can have more predictive value where it can help predict utility of chemotherapy for cancer patients,” says Dr. Aman Opneja, Medical Oncologist at Duke Cancer Center.
10. Will My Insurance Cover Molecular Testing?
NGS testing is usually covered by the Medicare program and many other insurance companies. If you discover that your plan does not cover the comprehensive NGS testing, talk to your cancer team. They may be able to work with your insurance company to get the test approved for you.
Types of NGS Testing On The Market
There are a number of tests you may encounter, depending on where you are getting treatment and what you are getting treatment for. Here are some of the common ones currently on the market:
- FoundationOne®CDx looks at 324 genes in solid tumors and says it can takes up to 12 days for results. Test results include microsatellite instability (MSI) and tumor mutational burden (TMB) to help inform immunotherapy decisions.
- OmniSeq Insight provides comprehensive genomic and immune profiling for all solid tumors. It looks for 523 different genes. Test results include microsatellite instability (MSI) and tumor mutational burden (TMB), as well as PD-L1 by immunohistochemistry (IHC).
- Cobas EGFR Mutation Test v2 identifies 42 mutations in exons 18, 19, 20 and 21 of the epidermal growth factor receptor (EGFR) gene. It is designed to test both tissue and plasma specimens with a single kit, and allows labs to run tissue and plasma on the same plate simultaneously.
You should ask your healthcare team if the brand of molecular testing they are doing is optimal for your cancer type.
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