Cetuximab and Radiotherapy for HPV-Associated Oropharynx Cancer
Name of the Trial
Phase III Randomized Study of Radiotherapy with Cisplatin or Cetuximab in Patients with Human Papilloma Virus-Associated Oropharyngeal Cancer (RTOG-1016). See the protocol summary.
Dr. Andy Trotti, Radiation Therapy Oncology Group
Dr. Maura Gillison, Ohio State University
Why This Trial Is Important
Oropharyngeal squamous cell carcinoma (OSCC) is a type of head and neck cancer that forms in the middle part of the throat, which includes the base of the tongue, the tonsils, and the soft palate. Although OSCC was once thought to be a single disease, recent research has revealed that it has two distinct types: cancers that test positive for human papillomavirus (HPV) and those that are HPV-negative.
Oropharyngeal tumors negative for HPV have been linked to tobacco and alcohol abuse, whereas HPV-positive malignancies may be related to sexual behavior. Patients with HPV-associated OSCC are likely to be younger at the time of diagnosis and have a better prognosis than those with HPV-negative malignancies. In contrast with the rates of other oral cancers, which have fallen as smoking rates have declined, the incidence of HPV-positive OSCC is on the rise.
Current treatment strategies for oropharyngeal cancer are based on tumor stage, rather than HPV status, and consist of surgery or radiation with or without cisplatin-based chemotherapy. Cancer response rates following cisplatin-based chemotherapy and radiotherapy are generally good, but studies have shown that this combination treatment approach dramatically increases toxic side effects. Since more than 80 percent of patients with HPV-positive tumors survive at least 5 years after diagnosis, these patients may do just as well on a less-toxic regimen.
One study investigating the combination of cetuximab, a monoclonal antibody directed against a protein called EGFR, and radiotherapy in head and neck cancer demonstrated improved patient survival compared with radiation alone. The use of this combination increased skin irritation, but otherwise it had the same side effects as radiotherapy alone. An analysis of patients in this trial revealed that those with OSCC who were male and younger, a group that mirrors the HPV-positive population, benefited most from the combination therapy. These results suggested that radiation plus cetuximab, instead of cisplatin-based chemotherapy, may reduce treatment toxicity without compromising cancer control for patients with HPV-positive OSCC.
In this clinical trial, patients with HPV-positive OSCC will be randomly assigned to receive cisplatin chemotherapy plus intensity-modulated radiation therapy (IMRT) or cetuximab plus IMRT. Prior to treatment, patients will complete a computer-administered survey on head and neck cancer risk factors, including tobacco exposure, alcohol use, and oral hygiene. During and after treatment, patients will also report the toxic side effects they experience. Clinicians will monitor the patients for tumor response, toxicity, quality of life, progression-free survival, and overall survival.
“This is the first randomized phase III trial specific to the HPV-positive patient population,” said Dr. Gillison. “There are a lot of quality of life outcomes incorporated [into the trial] about both acute toxicity and long-term toxicity, and the patients are reporting their toxicity experience directly on things like nausea, vomiting, ability to swallow, pain, and energy level using touch-screen surveys.
“It also includes things that we have never looked at before, which will allow us to do a cost-effectiveness analysis. The first potential outcome is that one of the treatments is better than the other. Then we get an answer in terms of disease control. If the two treatments are equivalent, then we see which one gives the patient the best quality of life. There is also the possibility that they are equal and one of them has a cost-benefit to society over the other,” Dr. Gillison added.