New blood test can detect most cancers before you show symptoms, study says
A new gene-based blood test has detected several types of cancer in a study of nearly 10,000 people with no history of the disease, researchers said, giving people a chance to find and fight the illness early on.
The results suggest that multi-cancer blood tests, combined with other screening procedures, could become a part of routine medical care, “in some cases leading to surgery with intent to cure,” the study said. But the researchers admitted more work needs to be done to get it ready for use.
The paper was published Tuesday in the journal Science.
“The ability to identify cancers through blood testing is one of the most exciting advances in cancer diagnostics,” the researchers said in the study. “The goal of earlier detection is to identify the presence of cancer at a stage when a treatment is more likely to be successful, thereby offering a better chance of long-term survival.”
Previous research has shown that most people who die from cancer aren’t diagnosed until they start showing symptoms, the paper revealed, but similar studies on cancer-detecting blood tests have only been done with people who have already been diagnosed with a disease.
“There is thus a need and an opportunity for minimally-invasive, multi-cancer screening tests to reduce morbidity and mortality from these diseases,” the researchers said, especially since standard screening is not recommended for “average-risk” people due to unnecessary exposure to radiation.
A total of 9,911 women participated in the study and were recruited from the Geisinger Health System in Pennsylvania and New Jersey, according to the study.
The test, which looks for cancer DNA in people’s blood, was created by Johns Hopkins University doctors who formed a company called Thrive Earlier Detection.
The blood test detected 26 cancers. If the first test suggested the presence of cancer, then the researchers administered another one. If the second test also yielded a positive result, then the patient received a whole-body PET scan to confirm it, the study said.
These usual screenings, which “cost around $1,000 and can reveal the location of any tumors,” the Associated Press reported, detected another 24 cancers.
Forty-six additional cancers were found for other reasons, the study said.
The blood test searched for all cancer types except those of the skin, central nervous system and blood, such as leukemia, “which have very low likelihood of being detected by a blood-based screening test such as that used here,” the researchers said.
Although the study hailed positive results, the blood test is a long way from perfect.
It missed more cancers than it found and raised some false positives that led to unnecessary procedures, the AP reported.
The researchers said false positives can cause anxiety, and some cancers, if found with a blood test, may never even progress to a state that’s “clinically meaningful,” meaning it won’t be harmful to the patient, according to the study.
Nevertheless, one Italian cancer specialist called the test “extraordinary” and said it could become of value if improved, the AP reported.
The study also only tested women between 65 and 75 years of age because this demographic has a higher risk for cancer but is still young enough to benefit from early detection, the study said.
The researchers noted that men and people of more diverse backgrounds need to be studied in the future.
“This is not at the place where it could be used today,” Dr. Len Lichtenfeld, deputy chief medical officer for the American Cancer Society, told the AP. “It will need many more studies to demonstrate value, including whether it improves survival,” he said.
Rosemary Jemo, a 71-year-old hairdresser and exercise instructor, was diagnosed with ovarian cancer after her blood test showed signs of the disease, according to the AP.
The tumor was already the size of a football when doctors surgically removed it, the outlet said.
“I would have never known... I didn’t feel anything,” Jemo said.
This story was originally published April 30, 2020 at 12:27 PM with the headline "New blood test can detect most cancers before you show symptoms, study says."
