CHICAGO — A blood test to detect cancer mutations produced results that generally agree with those of an invasive tumor biopsy, researchers reported, heralding a time when diagnosing cancer and monitoring its progression may become less painful and risky. ADVERTISING
CHICAGO — A blood test to detect cancer mutations produced results that generally agree with those of an invasive tumor biopsy, researchers reported, heralding a time when diagnosing cancer and monitoring its progression may become less painful and risky.
The blood tests, known as liquid biopsies, represent one of the hottest trends in oncology. They take advantage of the fact that DNA fragments from tumors can be found in tiny amounts in the blood of patients with cancer.
Researchers hope that such tests can become alternatives to conventional tumor biopsies, in which a piece of the tumor is extracted by needle or by surgery — procedures that can have complications.
The results of the study, the largest to date of a liquid biopsy test, give some reassurance that this might be possible.
The liquid biopsies are not used to diagnose cancer but rather to monitor disease progression or to detect genetic mutations in the tumor that could suggest which drug should be used to treat the disease.
The study looked at the results of more than 15,000 liquid biopsies performed by Guardant Health, a Silicon Valley start-up that is one of the leaders in the field. While many liquid biopsy tests now look for only a few mutations, Guardant’s test, which has a list price of $5,800, looks at mutations in 70 cancer-related genes.
The 15,000 samples came from the blood of people with various types of cancer, including lung, breast and colorectal. The researchers on the study, most of whom worked for Guardant, said the frequency and types of mutations found were similar to what is known from scientific literature.
For almost 400 patients, tumor biopsies were available, allowing for direct comparison to the blood test results from the same patient. For certain mutations that drive tumor growth, if a particular mutation was found in the blood, it was also found in the tumor 94 percent to 100 percent of the time.
Dr. Edward Kim, an expert on lung cancer mutations who was not involved in the study, said the results showed the liquid biopsy accuracy was “very good.” He said, however, that use of an actual tumor sample allows for a more thorough analysis, including more mutations than is possible with a blood sample.
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