A new regimen treatment for HPV-positive oropharynx cancer patients
Patients with HPV-positive oropharyngeal cancer may benefit in the future from a treatment less toxic than the current Intensity-Modulated Radiation Therapy (IMRT), which is the standard treatment. The study results will be presented at the 49th Annual Meeting of the American Society of Clinical Oncology by Shanthi Maruri, who is first author on the study and an oncologist at the Johns Hopkins Sidney Kimmel Comprehensive Cancer Center.
Oropharynx cancer refers to a malignant tumor that develops in the oropharynx, which is the middle portion of the neck. In general oropharynx tumors are either HPV-positive, that is associated with human papilloma virus, and which generally have a better prognosis, or HPV- negative that are generally associated with smoking or alcohol. Signs and symptoms announcing such cancers are difficulty in swallowing, voice changes, coughing, pain or hearing changes, weight loss, fatigue and others. In general risk factors for oropharyngeal cancer are alcohol, smoking, exposure to asbestosis, infections with HPV and EBV (Epstein Barr virus), various genetic mutations. Treatment consists of removing the tumor in addition to chemotherapy and radiotherapy, but in some cases the cancer cannot be operated. Regarding oropharynx cancer, studies have shown that combination therapy consisting of radiotherapy and chemotherapy may be as effective as surgery.
Now researchers at Fox Chase Cancer Center have completed a phase 2 clinical trial that aimed to identify those patients with HPV-positive oropharyngeal cancer who do not require total dose of radiation. The 90 patients included in the study received chemotherapy and treatment with cetuximab, a monoclonal antibody which is part of the targeted treatment. The patient’s response to initial treatment determines the dose of irradiation. Barbara Burtness, senior author on the study and chief of head and neck medical oncology at Fox Chase, said that patients who respond well to chemotherapy have high chances to respond well to radiotherapy. Therefore, using a total dose of irradiation in these patients (who respond well to chemotherapy) would mean an overtreatment.
The results showed that the majority of patients included in the study tolerated well the induction chemotherapy and cetuximab treatment, and that 46% of them had complete clinical response. All these patients received a lower dose of radiation: 54 Gy compared with the standard dose of 66- 70 Gy. It was found that in these patients the rate of high-grade side effects due to irradiation (difficulty swallowing, dry mouth) was lower. Although the results are promising, it is still early to draw definitive conclusions.