Blood Test May Identify Candidates for Early Lung Cancer Screening
Could a simple, inexpensive blood test help detect which people to screen earlier for lung cancer, potentially saving lives? Samir M. Hanash, M.D., Ph.D., of The University of Texas MD Anderson Cancer Center in Houston believes it is an untapped opportunity.
An international research team, which included Hanash, found that a four-protein biomarker blood test can extend the reach of computed tomography (CT) screening beyond people with heavy smoking history, and with more accuracy.
Current guidelines from the U.S. Preventive Services Task Force (USPSTF) only call for CT screening in adults aged 55 to 80 with a 30 pack-year smoking history who either smoke or have quit within the past 15 years.
“The question is, how can we catch their cancer early?” Hanash, professor of the Department of Clinical Cancer Prevention and director of the Department of Red and Charline McCombs Institute for the Early Detection and Treatment of Cancer, told CURE in an interview. “This study shows that a blood test has the potential of catching lung cancer early even though those subjects based on their smoking history would not have been eligible for screening by CT.”
In a validation study, published in JAMA Oncology, the team compared a model based on smoking history with an integrated model that included the biomarker score based on four markers plus smoking history. “The key to selecting the biomarkers was the availability of blood samples taken from people before they had developed the disease,” Hanash said.
The four proteins used for the biomarker risk score included: the precursor form of surfactant protein B; cancer antigen (CA) 125; cytokeratin-19 fragment and carcinoembryonic antigen.
“Knowing that they are positive puts them at high risk of actually having cancer even though they may not have symptoms, prompting a low dose CT to rule out presence of lung cancer,” Hanash said.
The study included 63 ever-smoking patients (meaning anyone who had a history of smoking) who developed lung cancer within a year of initial blood sample collection compared with 90 matched controls in two large European population-based groups. Researchers determined that the test with biomarkers identified 63 percent of future lung cancer cases (40 of 63) compared with 42 percent (20 of 62) based solely on smoking history.
“The majority of patients that are diagnosed with lung cancer are not at the 30-pack years smoking history to be eligible for CT screening,” Hanash said. “The concern is that as the smoking rates go down, more and more lung cancers are not going to be associated with 30-pack years of smoking. So, what do we do? What this test suggests is that anybody who has a smoking history could get the blood test and if they turn out to be positive that should trigger a CT.”
Hanash went on to explain that the test could be as simple as using the same blood draw for another test, such as cholesterol. “The issue is saving lives,” he said. “There’s no stigma associated with getting a blood test.”
Findings from this study must now be validated in larger studies and researchers note that they must fine-tune the biomarker-based prediction model.