By Admin at 20 May 2016, 07:56 AM
Genetic mutations are known to be involved in some cases of lung cancer. Certain medications are available to directly target such mutations, but first the tumor must be tested to uncover what, if any, genetic mutations are present.
Surgical biopsies are often used for this purpose, but they have limitations, including risks of side effects like a collapsed lung. A blood test dubbed a “liquid biopsy” presents a less-invasive alternative. Tumors shed DNA into the patient’s bloodstream, and the liquid biopsy detects this circulating tumor DNA (ctDNA) in the blood.
Researchers have remained skeptical of just how accurate liquid biopsies may be, but a new study found remarkable results. Researchers from the Dana Farber Cancer Institute in Boston developed a liquid biopsy to detect certain mutations in the epidermal growth factor receptor (EGFR) along with mutations in another gene called KRAS.
EGFR mutations are found in many lung cancer patients, while KRAS mutations may be found in smokers with lung cancer. The liquid biopsy was tested in 180 lung cancer patients and “exhibited 100 percent positive predictive value for the detection of these mutations.”
In other words, the blood test, which is technically known as rapid plasma genotyping, was able to correctly identify the genetic mutations every time, allowing the oncologists to select the best targeted treatment and avoid repeat biopsies.
Along with being less invasive and safer than surgical biopsy, the liquid biopsy is faster, returning results in just three days compared to four weeks for surgical biopsy.
Dr. Wafik el-Deiry of the Fox Chase Cancer Center in Philadelphia expressed his enthusiasm for the study results to NBC News, "This study is not about the promise, it's about realizing the promise.”
The test proved so reliable that in April 2016, the Dana-Farber/Brigham and Women's Cancer Center (DF/BWCC) became the first U.S. medical facility to begin offering it to patients. All patients with non-small cell lung cancer are offered the test upon first diagnosis or relapse following previous treatment.
Senior study author Geoffrey Oxnard, MD, thoracic oncologist and lung cancer researcher at Dana-Farber and Brigham and Women's Hospital, explained:
“We see plasma genotyping as having enormous potential as a clinical test, or assay—a rapid, noninvasive way of screening a cancer for common genetic fingerprints, while avoiding the challenges of traditional invasive biopsies …
Our study was the first to demonstrate prospectively that a liquid biopsy technique can be a practical tool for making treatment decisions in cancer patients. The trial was such a success that we are transitioning the assay into a clinical test for lung cancer patients at DF/BWCC."
More than three-dozen companies are currently working on developing liquid biopsy tests for cancer, which will help cancer patients to get increasingly personalized treatment.
Sources:
JAMA Oncology April 7, 2016
NBC News April 7, 2016
Science Daily April 7, 2016
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