HPV infections cause about 80% of oropharyngeal cancers in the United States, according to the National Cancer Institute. More than 25% of these cancers recur, usually within the first 2 years after treatment. Yet one of the antibodies in these patients could be useful in identifying those at risk of such recurrence, according to the Johns Hopkins University School of Medicine.
“There are currently no reliable tests available to detect early recurrence, so we hope to find a biological marker that could help identify those most at risk,” said Carole Fakhry, MD, MPH, associate professor of otolaryngology/head and neck surgery at the school and a member of the Johns Hopkins Kimmel Cancer Center.
Fakhry and her colleagues have been researching the E6 antibody, which is strongly linked to the diagnosis of HPV-positive oropharyngeal cancer. E6 levels should fall when patients are treated and cured of the cancer. An increase in E6 levels after treatment, though, might indicate a higher risk of the cancer returning as the body produces it to fight HPV-related cancer proteins.
The researchers examined the health records and serum samples of 60 patients with HPV-positive oropharyngeal cancer treated at the Johns Hopkins Hospital. There were 6 cases of recurring cancer within an average of 4.4 years of follow-up after treatment. Patients with high levels of E6 before treatment were 7 times more likely than those with lower levels to see their cancer return.
While a blood test eventually could identify patients most at risk for a recurrence, Fakhry said, more data is needed to confirm E6’s use as a biomarker. Conducting a study of E6 on a large group of patients at the start of their treatment and drawing blood at predetermined points during therapy to examine E6 levels would be one of the best ways to proceed, she added.
Such tests could be useful in determining each patient’s follow-up care, such as whether and how often the patient might need imaging or clinical exams to watch for a cancer’s possible return, though more research is needed there as well.
“Potentially, a low-risk patient may need less stringent surveillance while a high-risk patients may require more intense imaging,” Fakhry said. “But this is far away from clinical practice, as we would really need to understand whether this hypothetical approach would improve lead time to diagnosis of recurrence and survival outcomes.”
The study, “Serum Antibodies to HPV16 Early Proteins Warrant Investigation as Potential Biomarkers for Risk Stratification and Recurrence of HPV-Associated Oropharyngeal Cancer,” was published by Cancer Prevention Research. It was funded by the Oral Cancer Foundation and the National Institute of Dental and Craniofacial Research.