New blood test 95% accurate at detecting cancer recurrence
Approximately one in five survivors of breast cancer, who underwent 5 years of chemotherapy and/or radiation, end up having a recurrence within 10 years. And, now, a new blood test has been developed that researchers say is 95 percent accurate in detecting a recurrence of breast cancer – and could help when it comes to tracking how well a patient is responding to treatment.
Researchers from the Johns Hopkins Kimmel Cancer Center in Baltimore released their findings recently in the journal, Cancer Research.
Study leader Saraswati Sukumar, a professor of oncology and co-director of the Breast Cancer Program at the Johns Hopkins Kimmel Cancer Center, said that the risk of recurrence after a breast cancer patient has been successfully treated is measured by routine blood tests and scans.
However, such tests are typically administered only when a patient reports certain symptoms, such as having pain, being short of breath and/or having aching bones. And even when a patient is not having any symptoms, standard blood tests and imaging can give false positive results; thus, leading to additional tests and biopsies that aren’t needed.
Accordingly, the researchers wanted to create a new, non-invasive test for detecting a recurrence of breast cancer sooner and with more accuracy than existing tests. They also wanted the test to be simple enough that it could be given during regular doctor visits.
As a result of their efforts, the researchers came up with a test referred to as the cMethDNA assay, which can monitor 10 breast cancer-specific genes in the blood of a patient.
The team scanned the genomes of breast cancer patients in the early stages of the disease in order to identify these genes. In addition, they also scanned the DNA of blood from those patients who had metastatic breast cancer.
After these scans, the team found 10 genes that are specifically altered in breast cancers, including 7 newly identified genetic markers that the researchers had previously linked with primary breast cancers.
To find out if a patient is at risk for a recurrence of breast cancer, the test looks for any signs of DNA hypermethylation in the breast cancer genes, as hypermethlation is a sign that the cancer will probably recur.
The researchers also conducted several experiments to test the accuracy of the test, including one that took 24 blood samples from metastatic breast cancer patients and 28 blood samples from healthy women who did not have breast cancer.
As a result, the researchers found that the blood test was 95 percent accurate at determining which women had breast cancer – and that high percentage of accuracy was consistently maintained in the other experiments the team conducted.
Morever, the highly accurate blood test was also able to determine how a patient was responding to breast cancer treatment as soon as 2 weeks. For example, if the patient responded well or had stabilized, the test detected a decrease in methylation in the cancer genes, whereas those who did not respond or had worsened, there was no decrease in methylation.
Sukumar said that these findings demonstrate how early detection to determine the effectiveness of cancer treatment can help tremendously in preventing unnecessary treatments, as well as prevent unnecessary exposure to highly toxic agents.
The research team also found that the test could be used to detect other recurrent cancers of the lung and colon.
SOURCE: Johns Hopkins Medicine, News Release: Blood test spots recurrent breast cancers and monitors response to treatment, April 15, 2014.