Can a newly developed blood test improve the early diagnosis of cancer?
To date, there is no test that can detect cancer at very early stages. A new universal blood test is said to identify eight of the most common types of cancer. Some physicians see tremendous progress in this, as the test could save many lives if the cancer was diagnosed early. German researchers reacted more cautiously.
In their current study, the scientists at Johns Hopkins University found that the newly developed blood test can easily and effectively detect various forms of cancer. The doctors published the results of their study in the scientific journal "Science".
In the future, an annual cancer test could save many people's lives
One of the biggest goals of medicine is a universal blood test to find cancer. Researchers have now taken a big step closer to this goal. The doctors developed a blood test that can identify eight common types of cancer. The experts hope that the development will lead to an annual test that will detect cancer early and thus save many lives. However, the scientists explain that more research is needed to assess the effectiveness of the test in the detection of early cancer.
How does the new blood test work?
Tumors release tiny traces of their mutated DNA and proteins, which they then release into the bloodstream. The newly developed test looks for mutations in 16 different genes that regularly arise in cancer. The test also identifies eight proteins that are frequently released in cancer.
Examination included over 1,000 subjects with cancer
The effectiveness of the test was checked on 1,005 patients with various types of cancer. These included, for example, cancer in the liver, stomach, pancreas, esophagus, intestine, lungs, breast or ovary, which had not yet spread to other tissues. The test found 70 percent of cancers.
Five of the eight types of cancer examined have no screening programs
Early detection of cancer can have a huge impact on cancer mortality, author Dr. Cristian Tomasetti from the School of Medicine at Johns Hopkins University. The earlier the cancer is recognized, the greater the likelihood of successfully treating the disease. There are no screening programs for five of the eight types of cancer examined. For example, pancreatic cancer has so few symptoms that it can only be recognized late. As a result, four out of five patients die of the disease in the year of diagnosis. Identifying tumors at a time when they can still be surgically removed would make a huge difference in the survival of those affected, adds Dr. Cristian Tomasetti added.
Blood test could complement existing screening tools
The test, called CancerSEEK, is currently being evaluated in patients who are not diagnosed with cancer. The usefulness of the test must now be shown in this investigation. Medical hope is that the new test will complement other screening tools such as breast cancer mammography and colon cancer colonoscopy.
Can other types of cancer also be diagnosed?
Increasing the number of mutations and proteins analyzed in the test could allow a wider range of cancers to be identified, the researchers explain. A blood test to diagnose cancer, without all other procedures such as scans or colonoscopy, has enormous potential, say the doctors. However, early diagnosis does not resolve the uncertainty as to how some types of cancer should be treated. If the cancer is not immediately life-threatening, treatment can in some cases be even worse than living with the disease, the scientists add.
Criticism from a German researcher
The assessment of German experts was critical. Udo Siebholt from the University of Halle and the Molecular Pathology Working Group of the German Society for Pathology doubted that the new test could meet the requirements of a screening test. “The sensitivity, specificity and robustness of the procedure would have to be very high in order to avoid unnecessary examinations, costs and uncertainty of the test subjects,” said Siebolt in the Ärzteblatt. The expert confirmed that the importance of cell-free DNA has not yet been conclusively assessed. Benign lesions such as Colon polyps, first genetic changes show. Therefore, due to the frequency, “false positive” results can often occur - more often than in the control group of the study. (as)