Biomarker may detect recurrence of HPV throat cancer

Researchers have found a potential biomarker that may detect the recurrence of human papillomavirus (HPV)-related oropharyngeal cancer, according to study published in the February 2016 issue of Cancer Prevention Research.

A clinical diagnostic test based on this finding would be years away, the researchers cautioned. Still, they add, this is a promising beginning toward detecting this growing form of cancer. HPV infection now accounts for about 80% of oropharyngeal cancers in the United States, according to the National Cancer Institute. Also, the cancer recurs in up to 30% of HPV-positive patients, largely in the first two years after treatment.

“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 the study’s lead author Carole Fakhry, MD, MPH, Associate Professor of Otolaryngology–Head and Neck Surgery at the Johns Hopkins University School of Medicine and member of the Johns Hopkins Kimmel Cancer Center, in Baltimore, MD.

In this retrospective study, Dr. Fakhry and colleagues hypothesized that HPV antibodies should decrease after successful treatment of the cancer. Conversely, an increase in those antibodies in these patients may signal a risk that the cancer is recurring.

To test this hypothesis, the researchers reviewed the health records and blood serum samples of 60 patients with HPV-positive oropharyngeal cancer (median age of 56) who were treated at Johns Hopkins Hospital. Most of the patients had samples taken before and after treatment. Of these, the researchers identified 6 cases of recurring cancer within an average of 4.4 years of follow-up after treatment.

Next, the researchers looked for four specific HPV cancer cell antibodies in these patients (E6, E1, E2, and E7), and confirmed that the average level of most of these antibodies was lower after treatment.

Importantly, patients who had high levels of E6 antibody before treatment were 7 times more likely than those with lower levels to have their cancer return. “If this finding is validated in a rigorous prospective study, then HPV serology may offer a novel prognostic biomarker to further stratify the risk categorization currently used for clinical trials,” the authors wrote.

More research is also needed to know whether such tests would be useful in determining the path of a patient’s follow-up care, such as whether and how often a patient might need imaging or clinical exams to monitor for cancer recurrence.

“Potentially, a low-risk patient may need less stringent surveillance while a high-risk patient may require more intense imaging,” Dr. Fakhry said. “But this is far away from clinical practice, as we would really need to understand whether this hypothetical approach [with E6] would improve lead time to diagnosis of recurrence and survival outcomes.”