A recent study conducted at the University of Michigan Health System found that a blood test can detect the recurrence of oropharyngeal cancer.
Oropharyngeal cancer occurs in throat, tonsils and back of the tongue. It is often connected to the human papilloma virus (HPV), which usually makes the cancer more responsive to treatment. However, in about 15 to 20 percent of patients, the cancer returns because the treatment failed, which cannot be detected through biomarkers.
However, this new study found that recurrence can be detected in its early stages by tracking patients’ antibody levels. Participants in the study who experienced recurrence of oropharyngeal cancer had higher levels of antibodies for two proteins found in HPV-related cancers, E6 and E7.
For the study, researchers looked at information collected for a previous study involving 52 patients with HPV-related advanced oropharyngeal cancer. Out of the participants, who were all similar in age, cancer classification and smoking status, 22 had developed recurrence and 30 had not.
Participants’ serum was evaluated through a blood test at the start of treatment, after treatment ended and every three months after that. Those who had a recurrence were diagnosed within three months of the blood samples used for the study. On average, a patient was diagnosed with a recurrence thirteen months after their treatment ended.
Soon after treatment, patients with recurrence and patients without had no difference in E6 and E7 antibody levels. All patients' antibody levels declined three months after treatment, which is to be expected since all or most of the cancer has just been eliminated.
Over time, however, researchers found that in patients whose cancer recurred, their E7 antibody levels did not decrease as quickly as their counterparts. Importantly, this could be detected before the recurrence was discovered.
When it comes to evaluating E7 antibody levels, every patient is different. Physicians must look at the patient’s specific baseline level rather than compare their levels to an absolute level. Over time, if E7 levels increase, it indicates recurrence, according to the study.
Currently, patients with oropharyngeal cancer go in for post-treatment checkups every few months to monitor the status of the disease and see if there is recurrence. This biomarker has the potential to change that and make the monitoring process easier on the patient, as they could have their blood drawn near home, and come into clinic if the E7 levels rise.
“The NCCN guidelines currently have us check patients for cancer every two to three months for the first year and every three to four months the second year,” explained researcher Matthew Spector, M.D., a physician and assistant professor at the University of Michigan. “This could bring us to a point where we're doing blood tests in addition to physical exams, or maybe even the blood test alone to determine if the patients’ cancers are coming back.”
Additionally, when oropharyngeal cancer recurrence is caught early, it allows physicians to remove the cancer in the throat or neck, often eliminating the disease. Cancer that spreads to the lungs can be treated with targeted therapies. The earlier the recurrence is caught, the better the outcome of treatment is expected to be.
Since this test to evaluate E6 and E7 antibodies is a standard laboratory test, implementation of this method should be inexpensive, according to the authors.
More testing with larger groups of patients is needed before this method of surveillance can be recommended to physicians. The University of Michigan team opened a controlled phase 2 trial to further evaluate the potential for E7 antibodies as a biomarker for recurrence.
“There are other markers in the blood that we're also looking at, not only antibodies,” Spector said. “We're really excited about this. I think it's going to expand not only for HPV-related cancers, but there are opportunities to detect this for other types of head and neck cancers.”