Background: According to Sturgis, the incidence of HPV-positive oropharyngeal carcinoma has increased dramatically in recent years. Although patients with HPV-positive disease have a better prognosis than those with HPV-negative disease, researchers are still seeking a better understanding of what group of patients is more likely to respond to treatment.
How the Study Was Conducted: Sturgis and colleagues used blood samples from 209 patients with previously untreated oropharyngeal carcinoma, including 96 who had confirmed HPV-positive disease, and screened the samples for HPV16 antibodies E1, E4-7, L1, L2, and the N-terminal and C-terminal fragments of E2. Samples were taken as part of the initial patient workup, six weeks after the end of treatment, and at six-month intervals up to three years.
Results: Patients who were positive for any of the E antibodies tested had improved overall and progression-free survival compared with those negative for the antibodies. The five-year overall survival estimate for patients positive for E antibodies was 87.4 percent compared with 42.2 percent for patients negative for E antibodies. The five-year progression-free survival estimate was 82.9 percent for antibody-positive patients compared with 46.1 percent for antibody-negative patients.
Patients with HPV-positive disease who were also positive for the NE2, E1, or E6 antibodies had an 80 percent reduced risk for death and a 70 percent reduced risk for disease progression.
No survival advantage was noted for the L antibodies tested in the study.
E proteins of HPV are antigens that play a role in HPV-mediated carcinogenesis, and L proteins are involved in the development of the virus shell, which are lost once the HPV DNA is integrated into human DNA, Sturgis explained.
Author Comment: In an interview, Sturgis said, ""We found that patients who were serologically positive to the E proteins of HPV16 had a better prognosis than those patients who were seronegative to these antigens. This seemed particularly true of patients who had tumors that we could confirm were HPV-positive.
"If this testing became commercially available it could not only be used as a means of identifying people who are at risk for oropharyngeal and other HPV cancers, but may also allow identification of HPV-related oropharyngeal cancer patients at greater or lower risk for cancer recurrence and death. These data further suggest that if we can modify patient immunity and increase a patient's E antibody response, we might be able to affect cancer outcomes," Sturgis added. "Clinical trials are now testing whether vaccines that can stimulate these antibodies have clinical utility in HPV-related cancers."
Main Finding(s): The presence of certain human papillomavirus (HPV)-16 antibodies in the blood was associated with improved rates of survival among patients with HPV-related oropharyngeal carcinoma.
Journal in Which the Study was Published: Clinical Cancer Research, a journal of the American Association for Cancer Research
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