CHAPEL HILL -- UNC Lineberger Comprehensive Cancer Center researchers found in a new study that lower treatment doses can be given successfully to a group of HPV-positive patients with oropharyngeal cancer of the back of the throat, leading to fewer side effects.
The study builds on previous research showing that oropharyngeal cancer patients who test positively for human papillomavirus (HPV) have higher response rates to radiation and chemotherapy and better prognoses than patients with HPV-negative cancer. In a study published online in the International Journal of Radiation Oncology Biology Physics, the researchers reported that 86 percent of a group of highly selected, favorable-risk HPV-positive patients were cancer-free after receiving the lower doses. The findings were also presented at the American Society for Radiation Oncology (ASTRO) annual meeting in San Antonio.
“This study shows promising data that suggests that we are probably over-treating these patients with the standard radiation and chemotherapy regimens,” said Bhishamjit S. Chera, MD, a UNC Lineberger member, an associate professor in the UNC School of Medicine Department of Radiation Oncology and the study’s first author and principal investigator. “We have shown that we may be able to safely lower the radiation and chemotherapy doses, while still maintaining excellent cancer control, and at the same time, reducing toxicity.”
There were 43 patients included in the phase II clinical trial who had favorable-risk, HPV-or-p16-positive oropharyngeal squamous cell carcinoma and a minimal smoking history
In the trial, the patients received weekly doses of 60 gray of radiation for six weeks and a dose of the chemotherapy drug cisplatin 180 milligrams per meter squared. The standard treatment is 70 gray for seven weeks and cisplatin 300 milligrams per meter squared, Chera said.
They checked the patients for complete pathologic response through a biopsy of the primary tumor site and after a limited neck surgery in the lymph node region. Eighty-six percent, or 37 out of 43 patients, had no evidence of cancer in their biopsy or surgical specimens after receiving the lower intensity chemotherapy and radiation treatment. The other six patients had microscopic residual foci of unknown significance that was removed in the planned biopsy and limited neck dissection, Chera said. All 43 patients were alive with no evidence of cancer recurrence at follow-up.
Chera also said they saw lower acute side effects under the lower treatment regimen. And while they hypothesized these earlier results are promising and should predict for excellent long-term cancer control and reduced long-term side effects, the researchers believe additional studies with the lower-dose radiation and chemotherapy regimen are needed.
Funding for this study was provided by the University of North Carolina School of Medicine Department of Radiation Oncology and the University of Florida College of Medicine Department of Radiation Oncology.
In addition to Chera, other study authors include: Robert J. Amdur, MD, of the University of Florida College of Medicine Department of Radiation Oncology; Joel Tepper, MD, of the UNC School of Medicine Department of Radiology Oncology and UNC Lineberger; Bahjat Qaqish, PhD, of UNC Lineberger; Rebecca Green, MS, of the UNC School of Medicine Department of Radiation Oncology; Shannon L. Aumer, MA CCC-SLP, of UNC Otolaryngology/Head and Neck Surgery; Neil Hayes, MD, MPH, of UNC Lineberger and the UNC School of Medicine Division of Hematology/Oncology; Jared Weiss, MD, of UNC Lineberger and the UNC School of Medicine Division of Hematology/Oncology; Juneko-Grilley-Olson, MD, of UNC Lineberger and the UNC School of Medicine Division of Hematology/Oncology; Adam Zanation, MD, of UNC Otolaryngology/Head and Neck Surgery; Trevor Hackman, MD, of UNC Otolaryngology/Head and Neck Surgery; William Funkhouser, MD, of the UNC School of Medicine Department of Pathology and Laboratory Medicine; Nathan Sheets, MD, of Rex Healthcare; Mark Weissler, MD, of UNC Otolaryngology/Head and Neck Surgery; and William Mendenhall, MD, of the University of Florida College of Medicine Department of Radiation Oncology.