Researchers at Mass Eye and Ear and Massachusetts General Hospital have developed a liquid biopsy test for head and neck cancer associated with the human papilloma virus (HPV). In a new study, the test was shown to be more accurate, faster, and cheaper than conventional testing methods.
Their report, published December 2 in Clinical Cancer Research, shows this liquid biopsy was more than 98 percent accurate and obtained a diagnosis 26 days quicker on average than conventional tissue biopsy. The cost of the novel test was 38 percent lower than standard methods. When the researchers combined the liquid biopsy with findings from routine imaging and physical exam to create a fully non-invasive diagnostic approach, diagnostic accuracy remained greater than 95 percent.
With HPV-associated head and neck cancer rates on the rise, there is a great need for more accurate, less-invasive, faster and less expensive diagnostic tests, according to authors of the study.
“Current diagnostic approaches for HPV-associated head and neck cancers are imperfect and invasive, which means patients often need repeat biopsies to get to the diagnosis, thereby delaying care and increasing uncertainty, not to mention the discomfort of the procedures.” said lead study author Daniel L. Faden, MD, a head and neck surgical oncologist and investigator in the Mike Toth Head and Neck Cancer Research Center at Mass Eye and Ear, and assistant professor of otolaryngology–head and neck surgery at Harvard Medical School.
Diagnosing a patient with HPV-associated head and neck cancer through conventional methods has limitations. Tests, such as surgical biopsy, are invasive, and others, such as fine needle aspiration, may require repeat biopsies. Further, biopsies, CT and PET imaging and physical exams can only detect cancers once they have grown to millions of cells and are “visible”.
In the study, researchers prospectively enrolled 70 individuals presenting with the new, assumed diagnosis of HPV-associated head and neck cancer and 70 control subjects from Mass Eye and Ear and MGH. All underwent routine physical exam and imaging.
The team found liquid biopsy was significantly more accurate than standard of care, with 98.4 percent sensitivity for identifying a positive result and 98.6 percent specificity for detecting a negative result. When liquid biopsy was combined with routine imaging and physical exam findings, diagnostic sensitivity was 95.1 percent and diagnostic specificity was 98.6 percent. The average time from first presentation to a health care provider to diagnosis was 15 days, 63 percent less than typical methods (41 days).
Costs of the liquid biopsy were also significantly lower than conventional methods with an average estimated savings of over $6,000 per patient. Decreasing the time to obtain a diagnosis by a month is important to reduce the unsettling anxiety that patients experience between when they first present to a doctor with a concerning symptom, and when they eventually receive the diagnosis of cancer, according to Faden.
The custom liquid biopsy developed and applied in this study detects microscopic levels of HPV DNA in the blood. The test builds on the expanding field of cell-free DNA in cancer screening and diagnostics research. Cell-free DNA are fragments of DNA that break off cancer cells and are released into the bloodstream. While cell-free DNA can be difficult to detect for some cancers, HPV-associated cancers offer a major advantage because they release HPV DNA, which is only found in the bloodstream with the presence of an HPV-associated cancer.
