Blood test for early cancer detection a “paradigm shift” in screening

Researchers have hailed a possible “paradigm shift” in cancer screening after publishing the results of a study that used a simple blood test to detect signs of a range of different cancers.

The test can not only detect cancer, but also detect where in the body the signal for cancer comes from.

This helps medical professionals narrow down the tests that should then be done to confirm the diagnosis and begin treatment.

Some of the cancers identified during the study are also not currently being studied, meaning participants could start treatment earlier than previously possible.

Earlier cancer diagnosis increases the chances of successful treatment.

“To bend the cancer mortality curve will require earlier detection of more cancer,” said Josh Ofman, the president of GRAIL, the company behind the testing technique.

The test was conducted in the United States, where more than 600,000 people die from cancer each year.

“Unfortunately, with the demographic tidal wave, the cancer burden will increase as the absolute risk of developing cancer increases with age,” Ofman said.

“However, a world with more individual cancer screening tests is simply clinically and economically unsustainable given that each individual cancer screening test has a five to ten percent false positive rate.”

The test his company developed, called the Galleri test, could provide a “paradigm shift” in cancer screening “by finding more cancers at earlier stages with a single blood test,” he added.

How does the Galleri test work?

The blood test involved a single blood sample from the patient, which was then tested for methylation in the DNA – one of the hallmarks of cancer.

Methylation is when methyl groups – common units found in organic compounds – are detected in DNA. They don’t change the DNA code, but they can alter gene expression.

The test uses DNA sequencing and machine learning to analyze methylation patterns in DNA from blood.

This analysis can then detect cancer signals and predict where the cancer might be located in the body.

According to GRAIL, the Galleri test can detect signals from more than 50 types of cancer.

detect cancer earlier

The study, called PATHFINDER, involved 6,662 participants, all over the age of 50 and therefore at increased risk of cancer.

A cancer signal was found in 92 participants, of whom 35 were diagnosed with a total of 36 different types of cancer.

Among the confirmed cancers, GRAIL says, 71 percent had cancers that are not routinely screened for, such as uterine and pancreatic cancer.

Forty-eight percent of the non-recurrent cancers found were in the early stages.

Predicting where the cancer signal came from in the body was 97 percent accurate.

“The PATHFINDER study is an exciting first step towards a fundamental change in the approach to cancer screening,” said Deb Schrag, chief of medicine at Memorial Sloan Kettering Cancer Center in New York.

She added that the study “provides a glimpse into the future” and offers the possibility of using blood tests to detect cancers “in their earliest and most treatable stages”.

Jeffrey Venstrom, chief medical officer at GRAIL, said the Galleri tests — when done in conjunction with standard screening — more than doubled the number of cancers detected.

These included stage I liver, small bowel, and uterine cancers, and stage II pancreatic, bone, and oropharyngeal cancers.

“This is particularly notable given that the PATHFINDER population was heavily screened with higher than average rates for mammography, colonoscopy, and low-dose CT (computed tomography) lung scans.”

The results of the study were presented at the 2022 European Society for Medical Oncology Congress in Paris.