Tailoring Cancer Treatment to the Patient: The Importance of Biomarker Testing in Precision Medicine

“There’s sort of two ways to give therapy in oncology. One relies of simply knowing that this is breast cancer and then you give various treatments that work in large fraction of those patients. And you see what happens. Unfortunately, when you do that, you’re treating large number of patients and only some of them have benefit,” Dr. Dejan Juric, medical oncologist at Mass General Cancer Center, tells SurvivorNet.

“We want to flip that pyramid. We want to see smaller number of patients treated, but with a large benefit. To do that, you need to select patients much, much better. And to do that, you do molecular profiling.”

What is Molecular Profiling?

Molecular profiling is actually utilizing various tests — one of the tests is next generation sequencing — to generate a genomic profile for the cancer, as well as identify important biomarkers that can define diagnosis, prognosis, and predict response to treatment.

This should be part of discussions between you and your healthcare team after a cancer diagnosis.

Next-generation sequencing is a super advanced tool that has changed how we study genes. It’s like a modern toolbox used by scientists to quickly and affordably read the instructions of an organism’s DNA or RNA. This has helped researchers read a lot of genetic information quickly — so they can understand entire sets of genes, find differences in genes, and study how genes work.

NGS has various names, which can be a bit puzzling. NGS is the same as next-generation testing, comprehensive genomic profiling, broad molecular profiling or high-throughput sequencing. It is also commonly referred to as molecular testing.

NGS isn’t a particular test for a specific type of cancer. Instead, it’s a group of tests or a technique that searches for all the genetic changes in a tumor’s genes.

How is Molecular Testing Performed?

“If you were to get NGS testing. It usually starts with a discussion with your oncologist, where we talk about ordering the test and why we would order it,” Dr. Hannah McManus, a genitourinary oncologist at Duke Cancer Center Genitourinary Clinic, told SurvivorNet in a previous conversation.

The test can be done via the cancer tissue that’s obtained during biopsy or surgery. She explained that this is the most common way of analyzing the cancer mutations.

“Most patients have already had a biopsy or a sample taken of the tumor, when they come to see their oncologist. And that [tissue] can be used for NGS testing,” Dr. McManus said.

Another way to do the testing is via blood — where the test can pick up the cancer DNA in the blood and analyze it for gene changes. This is known as a liquid biopsy.

What is a Liquid Biopsy?

“You can — with a single tube of blood that’s sent for analysis — analyze something called circulating tumor DNA. This is a very straightforward test for a patient. They just need a blood draw,” Dr. Juric explains.

“There is simply no reason now not to test and detect such an important driver of disease that can lead to a much more optimal therapy as opposed to just giving chemotherapy or giving more aggressive treatments where there is no biomarker.”

“These approaches are now very reliable. In early days, we struggled with sensitivity … We couldn’t detect the mutations even when we knew they were there. But now the tests are much better and a lot more straightforward to do,” says Dr Juric.

Getting the Results: What to Expect

Most results from the NGS testing on tissue biopsy are available within two to three weeks from the date the tumor sample is received by the laboratory.

A liquid biopsy is much faster and typically arrives within a week.

Both the results are sent to your oncologist so that they can discuss how they may guide your treatment.

Will My Insurance Cover NGS 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.

Sometimes the company that runs the test may contact your insurance company on your behalf to waive the cost. There’s also the Next Generation Sequencing (NGS) Affordability Program to help lower your cost.

Immunotherapy and Targeted Therapy

An exciting new option for patients with several different types of cancer is a treatment known as immunotherapy. Undergoing molecular testing may help your doctors determine if a specific type of immunotherapy is likely to work for you.

Immunotherapy drugs stand out as a truly personalized therapy for cancer because they harness the patient’s own immune system to seek out and destroy cancer cells. This type of treatment can help patients live longer, healthier lives.

How Does Immunotherapy Work?

Normally, white blood cells find and destroy abnormal cells, but cancer cells learn to hide from them so they can continue growing and spreading.

Immunotherapy drugs find the cancer cells in their hiding places by blocking proteins that shield them. Once the cancer cells are uncovered, the immune system can do its job properly.

Another advantage to immunotherapy: because these drugs zero in on cancer cells while leaving much of the surrounding healthy tissue alone, they tend to be less toxic compared to traditional chemotherapy or radiation therapy which bombard both cancerous and healthy cells.

Immunotherapy can also provide a longer-lasting response by training the immune system to recognize and remember cancer cells, potentially reducing the risk of the cancer coming back.

The approach can be life changing — and possibly even life saving — for many patients. Make sure you ask your doctor about precision medicine and immunotherapy.

Questions to Ask Your Doctor

• Should I have next-generation sequencing testing?
• Do you need both the tissue sample and blood samples for NGS testing?
• Do I have any genetic mutation that would change the course of my treatment?
• Am I eligible to receive targeted therapy? What about immunotherapy?
• Is there a clinical trial that would be relevant for me?

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