Simple blood draw can detect more than a dozen cancers… including those often caught too late

A simple blood draw may be able to detect more than a dozen cancers, including those that don’t currently have standard recommended screenings and some that are often missed in early stages. 

A new study of nearly 36,000 people found that a blood test – akin to a routine outpatient blood draw – designed to detect multiple cancers was able to identify cancer signals across 17 different types, including ovarian, lung, breast and colorectal cancers. 

The multi-cancer early detection (MCED) test analyzes small fragments of DNA that cells release in the bloodstream. 

Among the participants, 287 returned a positive MCED test and cancer was diagnosed in 173 of those participants. 

Overall, the MCED test had a positive predictive value of 60.3 percent, meaning about six in 10 people who got a positive MCED result were ultimately diagnosed with cancer. 

It also had a specificity of 99.6 percent, meaning it correctly returned a negative result for the vast majority of people who did not have cancer. 

Among the participants who got a true-positive result, the MCED test correctly identified the cancer’s origin as one of its top two predictions in about 91 percent of cases.

And a majority of the cancers detected by the MCED were types without official screening recommendations. 

The multi-cancer early detection (MCED) test is akin to a routine outpatient blood draw

Dr Karthik Giridhar, a Mayo Clinic medical oncologist and senior author of the study, said: ‘One of the challenges in cancer screening is that most cancers do not have an established screening test. 

‘This study helps us better understand how a multi-cancer blood test might complement existing screening approaches by identifying cancer signals that otherwise may not be detected through routine screening.’

The cancer types detected by the MCED test included anal cancer, bladder and urothelial tract cancer, breast cancer, colorectal cancer, head and neck cancer, kidney cancer, liver and intrahepatic bile duct cancer, lung cancer, lymphoid cancers, myeloid cancers, ovarian and fallopian tube cancer, pancreatic, extrahepatic bile duct and gallbladder cancer, plasma cell cancers, skin cancer, stomach cancer, thyroid cancer and uterine cancer. 

Among the 151 participants with at least one newly diagnosed cancer detected by the MCED test, the study, published in the journal Nature Medicine, 53 percent had stage 1 or 2 disease and 71 percent had stage 1, 2 or 3 disease.

Of these, only breast, colorectal and lung cancers have a USPSTF grade A or B screening recommendation.

A grade A or B recommendation is set by the US Preventive Services Task Force (USPSTF).

Grade A recommends the screening because there is a high certainty that the benefit of a screening is substantial. Grade B recommends the screening because there is high certainty that the benefit is moderate or there is moderate certainty that the benefit is moderate to substantial.

A Grade A or B recommendation means that clinicians should offer or provide a certain screening test to people who meet specified criteria. 

For breast cancer, the screening is a mammogram; for colorectal cancer, it’s a colonoscopy and other stool- or imaging-based tests; and for lung cancer it’s a low-dose CT scan. 

For the 14 cancers without official recommendations, screening or monitoring can vary based on risk factors, lifestyle factors and family and medical history.

For example, for anal cancer, an anal Pap test may be performed in high-risk populations, such as people with HIV and for head and neck cancers, doctors can perform visual and hands-on exams to check for abnormalities. 

The MCED evaluated in the study was an earlier version of GRAIL’s Galleri MCED test. Galleri is  available in the US via prescription, although the current version has replaced the one used in the study 

However, for others, including ovarian and fallopian tube cancer, studies looking at the benefits of certain screening tools in average-risk women – a transvaginal ultrasound and specific blood test – haven’t produced sufficient evidence of any benefit to support routine population-wide screening. 

As a result, some of these cancers are often not caught until they’re in later stages, when the disease has spread to other parts of the body and it is harder to treat. 

While the MCED test is promising, Giridhar notes it is not yet a substitute for established cancer screenings. Instead, it may supplement existing screening approaches and help expand experts’ knowledge of cancer detection. 

The MCED evaluated in the study was an earlier version of GRAIL’s Galleri MCED test. 

Galleri is now commercially available in the US via prescription from a doctor, although the version currently sold has replaced the version used in the study.

Galleri is not yet FDA-approved and the agency is reviewing the application. 

On Wednesday, however, an FDA advisory committee voted 7-2 that the test’s benefits outweigh the risks. 

The test is currently marketed for adults at an elevated cancer risk and is priced at $949. 

The study was funded by GRAIL, the company that makes the Galleri test, and several of the study’s authors reported financial ties to the company, including employment, stock ownership or consulting roles.