Did you know that the 12 most dangerous types of cancer account for more than 60% of cancer-related deaths annually? Unfortunately, doctors cannot screen for most of these cancers before symptoms advance.
But hope may be on the horizon.
Researchers have developed a blood test that accurately detected more than 67% of these cancers, including pancreatic, lung, and ovarian cancers.
The U.S. and U.K. scientists reported their findings in the Annals of Oncology. Editor-in-chief Prof. Fabrice André said, “This is a landmark study and a first step toward the development of easy-to-perform screening tools. Earlier detection of more than 50% of cancers could save millions of lives every year worldwide and could dramatically reduce morbidity induced by aggressive treatments.” 
As part of a more extensive study of 15,000 people, the researchers tested blood from more than 4,800 people; about half of them had cancer. The test included more than 50 types of cancer.
In 93% of the samples, the test accurately predicted where cancer developed in the body in 96% of the samples. The false-positive rate was 0.7% (less than 1% would have an inaccurate diagnosis of cancer using the test).  For comparison, breast cancer screenings return a false-positive rate of about 10% of the time.
At this time, diagnostic tools can help doctors diagnose cancer after symptoms have developed. Too often, it is too late for curative treatment. For breast cancer (mammograms) and cervical cancer (Pap smears), these detect cancer at an earlier stage.
The new blood test can detect cancer, in many cases, before symptoms develop. In layman’s terms, the test zeroes in on cell-free DNA, which is released by tumor cells. The cfDNA has a chemical – a methyl group – that is associated with tumor growth.
Once the cfDNA is isolated from the blood sample, lab workers can enter the results into a computer, which recognizes DNA from cancer. The computer then predicts whether a person has cancer and what type of cancer it is.
Dr. Michael Seiden, the senior study author, said the test offers “the ability to detect multiple deadly cancer types with a single test that has a very low false-positive rate, and the ability to identify where in the body the cancer is located with high accuracy to help healthcare providers to direct next steps for diagnosis and care.
“These data support the ability of this targeted methylation test to meet what we believe are the fundamental requirements for a multi-cancer early detection blood test that could be used for population-level screening,” he said.
More research is needed before the blood test becomes a mainstream tool for oncologists.
“These tests, to be definitely helpful, must be able to detect cancer early and improve survival,” said Dr. Sunil Gandhi, a volunteer medical adviser of the Citrus Unit of American Cancer Society. “In other words, people should live longer and better before this can be used. … We need to do a large-scale study of persons without cancer. We need to show whether this can pick up early cancer, which could have been missed without the test.” 
 Blood test can detect 50 different types of cancer. https://www.medicalnewstoday.com/articles/blood-test-can-detect-50-different-types-of-cancer
 Sensitive and specific multi-cancer detection and localization using methylation signatures in cell-free DNA. https://www.annalsofoncology.org/article/S0923-7534(20)36058-0/fulltext#sec3
 Cancer & Blood Disease: Blood test to detect cancer. https://www.chronicleonline.com/lifestyle/health/cancer-blood-disease-blood-test-to-detect-cancer/article_12286a1a-7d96-11ea-8cbb-574e51f36295.html