Researchers found that patients whose oropharyngeal cancer recurred had higher levels of antibodies for two proteins, E6 and E7, which are found in HPV-fueled cancers. The finding suggests a potential blood-based marker that could predict when cancer is likely to return. A new study suggests the possibility of predicting at its earliest stages when a type of head and neck cancer will come back.
Oropharyngeal cancer — which occurs in the throat, tonsils, and back of the tongue — is frequently linked to the human papilloma virus. That’s good news, in a way, as HPV-related cancers are generally more responsive to treatment. Though in about 15-20% of these patients, treatment won’t work and relapses happen. There are no known biomarkers to predict when the treatments are likely to fail.
In a new study in Clinical Cancer Research, researchers found that patients whose oropharyngeal cancer recurred had higher levels of antibodies for two proteins, E6 and E7, which are found in HPV-fueled cancers. The finding suggests a potential blood-based marker that could predict when cancer is likely to return.
The study:
Researchers enrolled 52patients with advanced oropharyngeal cancer who had participated in the previous study: in which 22 patients had developed recurrence and 30 had not. These two groups were similar in age, cancer types and smoking status. All tumors were linked to the human papilloma virus. On average, cancer recurred 13months after a patient’s treatment ended.
Serum was measured via a blood test diagnosis or the start of treatment, then repeated after treatment ended and at about every 3 months later. Initially, there was no difference in E6 and E7 antibody levels between those patients who had relapses and those who didn’t. All patients showed a decline in their antibody levels 3 months after their treatment.
Since oropharyngeal cancer almost never recurs three months after treatment, antibody levels declined in all the patients studied. “Most patients recur within the first 2years, so the window period is to catch it after two years of treatment. Everyone’s level goes down over time, but some start to go up a little- and those are the ones we have to focus on”- says Spector.
Biomarkers:
Researchers evaluated the antibodies E6 and E7 in patients whose cancer recurred. The levels of E7 were not decreasing as quickly as patients who did not recur. And they could begin to detect that prior to the point when the recurrence was discovered.
“If we can monitor someone through blood markers, then instead of a patient coming for a clinic visit every two to three months, they could get blood drawn near home. If there’s evidence of high E7, we can tell the patient to come in for more evaluation,” Spector says.
The main factor is to look at the ratio of E7 antibodies. Every patient had a different baseline level, and the absolute level was not an indication. It is very patient-specific and had a different baseline. However, when you track it over the time, it rises and that is suggestive of recurrence.
Oropharyngeal cancer most commonly recurs in the throat, neck or lungs. If recurrence is caught early, surgery to remove cancer in the throat or neck can eliminate the disease and is likely to be a cure. If cancer spreads to the lungs, offering targeted therapies earlier might improve outcomes.
The test for E6 and E7 antibodies is a standard laboratory test that any cancer treatment facility could perform, so it would likely be inexpensive to implement.
More testing among a larger number of patients is needed. The U-M team has opened a phase II trial to assess the potential for E7 antibodies as a biomarker for recurrence.