A liquid biopsy-based test to diagnose HPV-associated cancers may offer improved accuracy at a reduced cost and with a shorter time to diagnosis compared to the current standard diagnostic approach that relies on tissue biopsy.
This is the conclusion of a recently published study, which found that a liquid biopsy used to diagnose patients with HPV-associated head and neck cancer was more than 98% accurate and associated with a quicker diagnosis by 26 days compared to using the standard tissue biopsy diagnostic approach (Clin Cancer Res. [published online December 2, 2021.] doi:10.1158/1078-0432.CCR-21-3151). Cost was also less expensive, with the liquid biopsy-based test carrying a 38% lower cost than the standard approach.
The findings were based on 140 prospectively enrolled patients with new or suspected HPV-associated head and neck cancer to test the hypothesis that a liquid biopsy developed by the researchers to detect circulating HPV DNA (ctHPVDNA) (70 cases) would improve diagnostic accuracy, at a lower cost, and at shorter diagnostic time than diagnosis with standard tissue biopsy (70 controls).
The study showed that the diagnostic accuracy of the liquid biopsy-based approach was significantly higher than the standard of care, based on a Youden index analysis that provides a composite value for both sensitivity and specificity (Youden index 0.968 vs 0.707, respectively, P<0.0001). The investigators also evaluated the combination of liquid biopsy with routine cross-sectional imaging and physical exam findings to create a combinatorial non-invasive diagnostic approach, which outperformed the standard approach (Youden index 0.937 vs 0.707, P=0.0006).
“These findings suggest that a fully noninvasive approach could be a viable alternative to traditional tissue biopsy in the future,” said lead author of the study, Daniel Faden, MD, a head and neck surgical oncologist at Massachusetts Eye and Ear in Boston, an assistant professor of otolaryngology–head and neck surgery at Harvard Medical School, and investigator at the Mike Toth Head and Neck Cancer Research Center.
According to Dr. Faden, the lower cost of the liquid biopsy-based test was based on extensive cost modeling and is largely due to the high costs of procedural interventions, such as operative biopsy or ultrasound guided fine needle aspiration with histopathologic review, currently used in standard diagnostic approaches.
Despite these promising results and the growing data that support using ctHPVDNA detection in HPV-associated head and neck cancers, he believes more data are needed to meet the extremely high burden of proof required to replace current diagnostic approaches with something new. “We must first generate much more data in larger and more diverse patient populations and settings and critically review these data as a community before this can become standard of care,” he said.
He and his colleagues are now working on developing an even more sensitive and more comprehensive second-generation assay, which, he says, should overcome one of the current limitations of the ctHPVDNA assay used in the study in which ctHPVDNA eludes detection in some patients. “For example, in our study, one out of 70 patients did not have ctHPVDNA detectable using our assay (sensitivity of 98.4%),” he said. “However, we believe this is a limitation of the technology platform that can be overcome with approaches we are now working on.”