A new blood test can screen for eight cancer types and help spot the tumor location, a recent study from Johns Hopkins Kimmel Cancer Center shows.
The research, “Detection and localization of surgically resectable cancers with a multi-analyte blood test,” was published in the journal Science.
The noninvasive test is called CancerSEEK. It simultaneously quantifies eight proteins and detects highly specific gene mutations related to cancer from DNA in the blood.
Collectively, the screened cancer types account for more than 360,000 (60 percent) of cancer deaths in the U.S. Importantly, five of these cancers – ovarian, pancreatic, stomach, liver, and esophageal – currently lack a screening test. The other cancer types covered by this test are colorectal, breast, and lung.
“The use of a combination of selected biomarkers for early detection has the potential to change the way we screen for cancer, and it is based on the same rationale for using combinations of drugs to treat cancers,” Nickolas Papadopoulos, PhD, the study’s senior author, said in a press release.
Unlike other tests aimed at identifying therapeutic targets, this test is intended solely for cancer screening. Researchers used data from more than three decades of cancer genetics research at their and institutions and others.
Regarding the test’s design, the researchers aimed to detect a small number of mutations for each cancer. This is crucial to limit false-positive screenings and keep the price low, Joshua Cohen, the study’s first author, noted.
From an initial pool of hundreds of genes and 40 protein markers, the investigators eventually trimmed their selection to 16 genes and eight proteins. The specificity for cancer was greater than 99 percent. Researchers found only seven false-positives out of 812 healthy control subjects. This high specificity is essential to avoid invasive follow-up tests and procedures for cancer diagnosis, the team noted.
A total of 1,005 patients with nonmetastatic, stages 1 to 3 cancers, including lung cancer, were then evaluated with Cancer SEEK. The test’s median overall sensitivity (the ability to find cancer) was 70 percent. The highest was for ovarian cancer (98 percent), whereas the lowest was for breast cancer (33 percent). The sensitivity for the five cancer types with no previous screening tests ranged from 69 to 98 percent.
A novel feature of Cancer SEEK “is that it combines the probability of observing various DNA mutations together with the levels of several proteins in order to make the final call,” said Cristian Tomasetti, PhD, one of the study’s co-authors. The test also uses sophisticated computer programming to help spot the location of a tumor in a small number of anatomic sites in a median of 83 percent of patients, Tomasetti observed.
Although the test does not cover all cancer types, nvestigators observed that expecting such a tool to be developed is not realistic.
CancerSEEK may be used with other routine blood work by primary care providers. Overall, the test shifts the focus from late-stage to early disease, which could be key in reducing cancer deaths in the long-term, the team believes.
“This has the potential to substantially impact patients. Earlier detection provides many ways to improve outcomes for patients. Optimally, cancers would be detected early enough that they could be cured by surgery alone, but even cancers that are not curable by surgery alone will respond better to systemic therapies when there is less advanced disease,” said Anne Marie Lennon, MD, PhD, a study co-author.
Importantly, the investigators predict that CancerSEEK will cost less than $500, which is in line with other single-cancer screening tests, such as colonoscopy.
Nonetheless, “to actually establish the clinical utility of CancerSEEK and to demonstrate that it can save lives, prospective studies of all incident cancer types in a large population will be required,” the team concluded.