“This blood test has exceptional performance in monitoring patients for cancer recurrence after radiation therapy,” Bhisham Chera, MD, an associate professor of radiation oncology at The University of North Carolina at Chapel Hill and a member of the UNC Lineberger Comprehensive Cancer Center, said in a press release.
Recent studies have shown that most patients with HPV-related oropharyngeal squamous cell carcinoma have detectable circulating tumor HPV DNA, according to Chera. “The data is very interesting in that it correlates as a biomarker for tumor burden and possibly also response kinetics of treatment,” he said.
Liquid biopsy tests have generated great interest recently, but it can be difficult to differentiate DNA from normal cells from that of tumor cells, the researchers said.
The test developed by Chera and colleagues is a multistep digital polymerase chain reaction assay that can detect as few as six molecules of HPV DNA in blood samples. It does not cross-detect other types of cellular DNA, according to Chera.
The researchers conducted a prospective, multinational biomarker study to evaluate the ability of circulating tumor HPV DNA to detect cancer recurrence after treatment.
The analysis included 89 patients with, all of whom underwent chemoradiation treatment.
“We analyzed about 1,000 blood samples for this study,” Chera said.
The cohort included 78 patients who underwent a de-intensified chemoradiation regimen of 60 Gy and 11 patients treated with standard-of-care 70 Gy.
Beginning 3 months after treatment, clinicians monitored patients with a combined approach of PET/CT scans, CT scans and chest X-rays at 6-month intervals. Clinicians also examined participants every 2 to 4 months for a 2-year period, and then at 6-month intervals for 3 more years. Blood samples taken during each visit were tested for ctHPV DNA.
“If a patient developed HPV DNA detectability in the blood during follow-up, throughout the course of the study, we started doing subsequent imaging because our results were very promising,” Chera said.
Patients were followed for an average of 19.8 months (range, 3.7-44.7). During the follow-up period, 70 of the 89 patients had undetectable HPV DNA levels. No cancer recurrence was observed among these patients. “We estimate that the negative predictive value of this blood test is 100%,” Chera said.
This is not a trial that changes practice today. It has enormous power to change practice in the future. Liquid biopsy technology is continuing to advance and generate new data for all sorts of solid tumors. It has shown the capacity to monitor and surveil post-treatment for recurrence, and the ability to detect emergence of new cancers. In this HPV head and neck cohort, the negative predictive value of 100% showing that those patients whose HPV DNA is nondetectable post-treatment, at least with the follow-up on the order of 20 months, is very compelling. This may offer a new opportunity to diminish the expense of complex imaging and utilize this blood to identify patients that may manifest recurrence.
- Paul Harrari, MD
- University of Wisconsin School of Medicine and Public Health
Disclosures: HemOnc Today could not confirm Harrari’s relevant financial disclosures at the time of reporting.