The team is looking for additional biomarkers detectable in blood and saliva that could make the HPV DNA test more specific.
Usually, patients with these cancers are examined every 1-3 months in the first year following diagnosis. However, the location of oropharyngeal cancers - tonsils, throat, base of the tongue - can make them less visible to physicians, so recurring cancer is usually only detected when patients report ulcers, pain or lumps in the neck.
Oral HPV infection has been shown to have a prevalence of 7% in the general population, with about 1% of the population having the high-risk HPV-16 subtype. This subtype is also linked with tumor progression.
The Johns Hopkins team wanted to investigate whether the DNA of HPV-16 could therefore be a useful biomarker to predict the recurrence of oropharyngeal cancer.
They analyzed blood and saliva samples, taken before and after treatment, from 93 oropharyngeal cancer patients.
The participants were being treated with surgery, radiation, or combined chemotherapy and radiation, at the Johns Hopkins Hospital and the Greater Baltimore Medical Center. Patients selected for the study had a variety of early-to-advanced stage cancers, and 81% of the patients had HPV-positive tumors.
Blood and saliva test is accurate in 70% of cases
The study reports that, when the HPV-16 DNA was detected in the saliva of patients after treatment, it was predictive of cancer returning in almost 20% of the cases. When the DNA was detected in the blood of the patients, the prediction accuracy rose more than 55%.
In a combined saliva and blood test, the presence of HPV-16 DNA was predictive of cancer recurrence in 70% of patients.
However, "we can't be sure our test results are cancer-specific and not due to other forms of HPV infection or exposure," warns Dr. Joseph Califano, professor of Otolaryngology - Head and Neck Surgery, member of the Johns Hopkins Kimmel Cancer Center and medical director of the Milton J. Dance Jr. Head and Neck Center at the Greater Baltimore Medical Center.
Further refinements to the test are essential to improve the detection rate. The team are now looking for other biomarkers detectable in blood and saliva that could make the HPV DNA test more specific.
Commenting on the test the team are developing, Dr. Califano says:
"There is a window of opportunity in the year after initial therapy to take an aggressive approach to spotting recurrences and intensively addressing them while they are still highly treatable. Until now, there has been no reliable biological way to identify which patients are at higher risk for recurrence, so these tests should greatly help do so."
Recently, Medical News Today wrote about a report from the Centers for Disease Control and Prevention (CDC) that found HPV vaccination coverage among teenagers remains "unacceptably low."