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Galleri test: Blood test for cancer

Galleri test: Blood test for cancer
Galleri test: Blood test for cancer

Until recently, most cancer screening exams were expensive and often uncomfortable, such as a colonoscopy. If the suspicion of a tumor is already concrete, a biopsy provides clarity: however, a needle sample of the questionable tissue is required. However, it would be lot easier if cancer could simply be recognized in the blood. The investigation is now underway.

Many of the new blood tests hunt for tiny fragments of tumor genetic material in the blood. Others hope to identify cancer by looking for specific sugar molecules that change during the course of the disease.The Galleri test is now the most advanced: it checks for cancer DNA in the blood. A simple blood sample, according to the maker Grail, can detect more than 50 forms of cancer. The test is also believed to be capable of determining the site of cancer in the body. The test, however, is not suitable for independent diagnosis. Grail suggests that it should be used as an addition to conventional cancer screening tests.

Initial successesDoctors in the United States are already permitted to perform the Galleri test. However, the test, which costs slightly less than $1,000, is not currently covered by health insurance in the country. The test has not yet been approved by the FDA. However, an initial study comprising approximately 6,600 people over the age of 50 has already provided preliminary data on the test's accuracy: A cancer signal was found in slightly under a hundred test subjects, and 35 of them had their cancer diagnosis confirmed. This suggests that over 40% of those who had a positive test result actually have cancer. Many of the malignancies discovered were in their early stages. The vast majority were kinds for which no conventional cancer screening exists. According to Susanne Weg-Remers, head of the Cancer Information Service at the German Cancer Research Center in Heidelberg, a large study involving 140,000 volunteers is now underway in the United Kingdom to test the accuracy and usefulness of the method, but it will be years before it is clear whether the test is suitable for widespread use. The doctor believes that blood testing for cancer could benefit patients who are particularly at risk.

What should you do in the event of a false alarm?

According to the findings of a study conducted in the United States, over two-thirds of people who tested positive did not have cancer. This represents 1% of the total number of test subjects. This is already causing new issues for practitioners and patients in the United States: "Of course, it is also a great burden on a healthcare system when a whole series of follow-up examinations are suddenly required, of which it is not yet known whether they would have been necessary at all," Weg-Remers adds. Aside from the substantial expenditures associated with such examinations, the psychological toll on individuals affected can be enormous. If the test is positive, more, potentially invasive cancer exams will be performed. According to Weg-Remers, if these are then negative, a worrisome sense often persists in the patients. This is yet another reason why cancer blood tests are still regarded troublesome for early detection.

Blood tests have long been used to track the progression of a malignancy that has already been diagnosed and to choose the best treatment. They can also be used to assess the success of cancer treatment and the likelihood of a relapse. Weg-Remers feels that blood tests for cancer detection will not be integrated into the entire concept of early cancer diagnosis for another ten to twenty years. Even then, she believes, they will need to be reinforced with traditional methods of early cancer detection. However, she is convinced that the blood tests will be able to improve tumor diagnosis in the long run.

Cancer can be treated more effectively if it is diagnosed early. Blood testing should detect cancer symptoms at an early stage - and with minimal effort. The investigation is now underway.The more people who are aware of these investigations and the more experts who are identified around the world, the faster progress will be made and goals will be met.

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