“Complexity is amazing.” The United States is planning a major blood test for many cancers science

Blood tests have begun to test healthy people for many types of cancer, which worries some doctors and scientists that they do more harm than good. Now, as part of President Joe Biden’s revived Cancer Month, the National Cancer Institute (NCI) plans to evaluate the promise of such tests.

Last week, NCI consultants approved a $ 75 million, four-year pilot study that included at least 24,000 people to evaluate the tests, which collected traces of DNA and protein, mostly from the blood shed by tumors. What these tests, sometimes called liquid biopsies, show can help the NCI decide to launch a long-term clinical trial to determine if it will save the lives of 300,000 volunteers between the ages of 45 and 70.

Companies such as GRAIL and Exact Sciences report that tumors are easier to treat at an early stage. GRAIL is offering a $ 949 test for people over the age of 50 and people at risk for cancer. He also launched a lawsuit involving 140,000 people in the UK. However, tests can skip cancer, lead to unnecessary procedures, and create false positives.

As a first step toward a pilot study, the NCI intends to confirm the company’s claims by using blood samples taken from people with cancer, along with other people who are believed to have cancer. Several tests will then be part of a pilot clinical trial starting in 2023 or 2024. Some participants receive one of the many cancer blood tests in addition to standard cancer screening, such as mammograms, while the control group receives only routine tests. One concern is that early detection of cancer by blood tests is a very attractive idea, so it can be difficult to find people who want to be part of a control group. Only if the pilot study is successful will the NCI then proceed to a larger follow-up study to assess whether previous diagnoses can reduce mortality.

“The challenges are astonishing,” Philip Castle, director of the NCI Cancer Prevention Division, told the agency’s advisory board last week. The advisers acknowledged the difficulties, but agreed on the importance of the effort. “I will sign the NCI. I think that’s very important, and they should do it, “said Sylvia Plevritis, a biomedical scientist at Stanford University.

scienceInsider recently discussed NCI’s ambitious plans with Castle; This interview was edited to be clear and concise.

Q: What does the NCI hope to learn from the pilot study?

THE: We need to understand issues such as working with blood and delivering blood to the company and getting results back. We need to know whether we can turn people into a control tool, it’s just a standard of care. It could be a breach of contract for people [to receive only standard cancer screening]Although we do not know whether these trials will actually benefit anyone.

Q: How do you stop testing more than 20 companies?

THE: They must have peer-reviewed, published information and demonstrate that they can replicate the results. They must be able to approve the test parameters and algorithm [that judges whether blood biomarkers indicate cancer]. They must also be able to perform sufficient tests. So we may be up to two or three who are really ready for a clinical trial.

Q: Are there specific tests like GRAIL and Exact Science tests?

THE: It is not clear whether these two wanted to be selected. Given that GRAIL now goes directly to consumers, participation may be hampered. [The company offers its test in a way that does not require U.S. regulatory approval.] Exactly, I think, is considering his own trial. We can balance the market by evaluating some second-generation technologies.

Q: What is a larger, longer-term clinical trial?

THE: That’s probably about 75,000 people for each textbook. So, if you have these three test and standard care hands, it will bring you to 300,000. We are thinking [the trial would run for] about 7-8 years. You can understand the amount of costs incurred. As far as I know, there has never been a major cancer screening study in the United States.

Q: Previous studies have estimated that 1% of participants will have a positive test for cancer, and then do some sections actually develop cancer?

THE: Among the positives [in past studies]Nothing was found in the third. One-third have no cancer, and another has a benign disease [the false alarm]. One-third of people are diagnosed with cancer.

Q: At the NCI conference, consultants were concerned that the tests would no longer be PSAs. (Prostate-specific antigen testing has become controversial because it often identifies small tumors of the prostate gland that may eventually be benign.)

THE: There is a lot of damage. The test may reduce advanced cancer, but it cannot reduce mortality. It can find lazy pain [slow-growing tumors] PSA does what you don’t want to do. We are concerned about the safety of diagnostic work [that is, whether a person who has a positive liquid biopsy will keep medical appointments to confirm or rule out cancer]. Of course you can [continuing] Even if you rule out cancer, the person who passed the positive test is worried. What are their future threats? Remember that not all of these diagnostic steps are perfect.

Conversely, when you take a negative test, they don’t meet the screening standard because they say, “Am I negative?” This may negate the benefits of these tests.

Q: Given the suspicions, why continue?

THE: Interestingly, we do not have screening tests for deadly cancers such as pancreatitis and ovarian cancer. We are helpless. But we need to put our emotions aside and make an effort to appreciate these technologies, and we need to be able to say with confidence what it can and cannot do.

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