Increasingly advertised and sponsored as game-changing, but how effective are they? Here is the principle on which they are based and for whom they are really already in use today (also in Italy)
The setup of blood tests that detect cancer before they give symptoms or are visible with the exams currently available, it is the subject of study in hundreds of researches all over the world, also funded by Bill Gates and Jeff Bezos. The great hope is to be able to discover the presence of a tumor only with a blood sample. When the disease is still in its very early stages and has not given any other symptoms. When timely and minimally invasive treatments can lead to more and more people definitively. The problem is that tests of this kind are increasingly advertised as revolutionarysponsored by the manufacturing companies. But how effective are they really? Am I able to really change the history of the fight against cancer or is it just a promotional strategy?
For a fee: the cost between 500 and 2 thousand euros
The question is rightly asked by many before putting their hands on their wallets (it is about test for sale at a variable figure between 500 and 2 thousand euros) and the theme has been taken up recently and in an article published in the scientific journal British Medical Journal. Where are we really at? “It is to make this hope closer that many scientists work every day,” he replies Anthony Russo, Professor of Medical Oncology at the University of Palermo -. The research is there, but we are not yet at “reality”. The test that uses blood as a surrogate for neoplastic tissue (the one obtained with the classic biopsy) even before the diagnosis of cancer itself can be defined as a real example of liquid biopsy in apparently healthy patients. And the liquid biopsy is a promising method that is already being used to monitor the evolution of the disease and adjust treatments, but for now it is not enough to arrive at a diagnosis». The principle on which the various tests are based is that the risk of cancer may already be written in our DNA a few years before the diagnosis and that these tests allow us to discover it well in advance. Or that they are able to intercept “cancer cells in circulation” in the body and therefore in the blood.
I study
During the last annual congress of the European Society of Oncology, held in September in Paris, we returned to talk about the test capable of accurately recognizing over 50 types of cancer and identifying in which tissue (i.e. organ) the tumor originates, before the disease gives clinical signs of its presence. What is it specifically about? “The PATHFINDER study analyzed circulating free DNA in the blood samples taken from 6,621 people, all over 50 and without a cancer diagnosis, it concerns a specific test, developed by American scientists who collaborate with a private company – specifies Russo, who is also president of the College of university medical oncologists (COMU) —. The test proved capable of identify a “carcinogenic signal” (alterations common to more than 50 different types of tumours) in 1.4% of the participants and, among these with a positive test result, the oncological diagnosis was subsequently confirmed in about 40% of the cases. Of the 6,290 healthy people, 99.1% actually received a negative test response. Practically the exam being tested demonstrated good accuracy in detecting cancer in those who had it and high specificity for healthy people. False positives, which then require lengthy and costly further investigations, were few. An important step forward, which however needs further confirmation.
The risk: unwarranted anxiety
Also because the stakes are high: for many experts, the greatest risk in the indiscriminate dissemination of tests for sale is that of create anxiety and indiscriminate fears. “These tests then require numerous other investigations to actually confirm the presence of a tumor – he explains Nicholas Normandirector of the Department of Translational Research at the Pascale Foundation Cancer Institute in Naples —: the danger, in the event of “false positives”, is that of having to carry out numerous useless checks. A waste for the health system and a huge load of anguish for those concerned”. Is it a convenient economic investment? “Not for individuals – explains Normanno -. To date, there is still no scientifically validated, effective test. Much proof of validity is still needed before having a mature tool that can be administered as universal screening, or “overall” on the entire healthy population. And, consequently, not even for the NHS. We already have effective, free screenings in Italy: la mammography for the early diagnosis of breast cancer, Pap test or HPV test for that to the uterus, fecal occult blood test for the colon”. Thus, every year, precancerous lesions or early stage carcinomas are discovered that are removed with a high probability of complete recovery for the patients. And recently a program financed by the Ministry of Health has been added, reserved for heavy or ex smokers, with spiral CT scan for lung cancer. For these exams the numbers, stemming from millions of people around the world, have shown all the advantages and possible disadvantages or risks (and the cons were judged inferior to the pros). And the successes have been measured, in terms of human lives saved and economic savings. Numbers that are still missing for the promising and sponsored “multicancer” blood tests.
February 9, 2023 (change February 9, 2023 | 09:16)
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