Liquid biopsies provide the biomarkers for targeted therapy for successful cancer treatment

The Island Now

BY BERTRAM DRACHTMAN

In medicine, a biomarker is a measure or indicator of the severity or presence of some disease states. More generally a biomarker is anything that can be used as an indicator of a particular disease state or some other physiological state of an organism.

Cancer is data starved. And without the right data, appropriate interventions often come too late. To select the best treatment, doctors and patients must have access to detailed genomic information about the disease. But this information is not easy to get. Traditional tissue biopsies require physical access to tumor tissue and come with serious risks for some patients. And for many patients, they aren’t even an option. In addition, they do little to help detect cancer early, when patients have the best chance at successful treatment.

Liquid biopsy, a process that gathers all its information from a simple blood test, is a test performed on blood to look for cancer cells or DNA from a tumor circulating in the blood.

Developing blood tests for early detection in high-risk populations and recurrence monitoring in cancer survivors is a goal of so many of the researchers today. Commercially available tests provide information that helps advanced cancer patients get the right treatment and helps drug companies get new therapies to market faster.

Targeted therapy is a cancer treatment that uses drugs. But it is different from traditional chemotherapy, which also uses drugs to treat cancer. Targeted therapy works by targeting the cancer-specific genes, proteins, or the tissue environment that contributes to cancer growth and survival

The National Institute of Health Writing in 2016, in a release from the National Cancer Institute wrote that “tumor biopsies are an essential part of cancer care. They can confirm a cancer diagnosis, identify the cell type of the tumor, and, increasingly are used to determine whether a patient’s tumor contains particular genetic alterations that may make them candidates for targeted therapies”

Going back to 2016, a study used blood samples from more than 15,000 patients with more than 50 types of tumors , compared a blood biopsy which profiles a type of mutation and chromosomal rearrangements in 70 cancer related genes, and detected alterations in these genes at the same distribution and frequency observed in previously published “genomic profiling studies” that used tumor biopsy samples.

The above study, was, by and large, highly consistent with gene alteration patterns reported in traditional tumor tissue testing In another component of the study, the researchers found the overall accuracy of the liquid biopsy in comparison with results from the tumor biopsy results was 87 percent. This accuracy increased to 98 percent when the blood and tumor samples were collected with six months of each other,

Today’s blood tests are enabling timely therapy selection for patients with cancer while also advancing programs for recurrence detection and early cancer detection

The key to conquering cancer is unprecedented access to its molecular information throughout all stages of the disease. Companies are developing a solution through tests that require only a blood sample.

Cancer has traditionally been described by where it found in the body, breast cancer, lung cancer, etc.
Today, we want to know what are the genetics of a specific cancer, its subtype, what mutations it may have, and as one report asks, what’s feeding it?

Just a bit more than two short years ago, the first liquid biopsy test was approved by the FDA for use in cancer. This was a test that uses key mutations in a gene that makes patients with advanced non-small cell lung cancer candidates for treatment with what is now known as aa “targeted therapy drugs”

The FDA approved the test previously for this indication using tumor specimens. The new use is for the detection of these mutations in circulating DNA from blood samples.

Cory Renauer writes In a National Institutes of Health Magazine, “Thanks to the Affordable Care Act, insurers are required to pay for recommended preventative services”. Last year, a study by the American Medical Association showed liquid biopsies outperformed actual tissue biopsies when it came to identifying targetable mutations.

In 2018, the writer talks of a blood test that could detect cancer earlier. The study called Cancer SEEK, is a unique non-invasive multi analytical test that simultaneously evaluates levels of either cancer proteins and the presence of cancer gene mutations from circulating DNA in the blood. Biomarkers or biological markers are in our blood, tissues, and other fluids

The use of a combination of selected biomarkers for early detection has the potential to change the way we screen for cancer, and it is based on the same rationale for using combinations of drugs to treat cancers.

This blood test was able to detect most cases of eight different kinds of cancer including some highly lethal forms- such as pancreatic, ovarian and liver-that currently lack screening tests.

Just weeks ago, a study called the NILE study, a head to head comparison of blood assay to standard of care tissue testing for the identification of guideline-recommended biomarkers in first line advanced non-small cell lung cancer was published in “Clinical Cancer Research” The study added to a growing body of literature that demonstrates the diagnostic tool for a genomic biomarker detection in advanced NSCLC can increase the number of patients tested for guideline-recommended biomarkers.

The guidelines resulted in testing for three times as many patients as a standard of care tissue testing. Also, when both the blood biopsy and the tissue testing where both available for a given patient, they were in agreement in more than 90% of the cases. The median time to results for the blood biopsy was 9 days versus 15 days for tissue testing.

Knowing the status of the guideline-recommended biomarkers is important before beginning treatment for several reasons. Up to 30 percent of patients can be treated with targeted therapies that often have a higher response rate than chemotherapy or immunotherapy.

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