ASCO Annual Meeting
May 30, 2014
Early research suggests that lowering the dose of radiation therapy for some people with oropharyngeal cancer is an effective treatment option and may help reduce long-term side effects. This new approach customizes the radiation dose based on a person’s response to initial chemotherapy, as well as other factors known to affect a person’s chance of recovery, such as whether the tumor has tested positive for the human papillomavirus (HPV), the tumor’s size, and the person’s smoking history.
Approximately 70% of newly-diagnosed oropharyngeal cancers are related to HPV, and the number of people diagnosed with HPV-related head and neck cancers appears to be increasing. People diagnosed with HPV-positive oropharyngeal cancer tend to have better survival rates compared with patients with HPV-negative disease, which is usually related to tobacco use.
As part of this study, 90 patients with stage III, IVa, or IVb HPV-positive oropharyngeal cancer received induction chemotherapy with cetuximab (Erbitux), cisplatin (Platinol), and paclitaxel (Taxol) before radiation therapy. After chemotherapy, 62 of the patients had no signs of cancer based on an endoscopic exam and were assigned to receive a lower dose of intensity-modulated radiation therapy (IMRT). The rest of the patients enrolled in the study received a standard dose of IMRT. IMRT uses advanced technology to more accurately direct the beams of radiation to the tumor, helping reduce damage to nearby healthy cells. Both groups were given standard cetuximab along with radiation therapy.
Two years after treatment, 93% of the patients who received the lower dose of IMRT and 87% of patients treated with the standard IMRT dose were alive. Eighty percent (80%) of the low-dose group and 65% of the standard-dose group had tumors that did not grow or spread further during this time. Survival was slightly higher (96%) for people in the low-dose group who had smoked less than 10 pack-years and had earlier-stage disease.
Lowering the dose of IMRT can also lead to a better quality of life by decreasing the risk of serious long-term side effects, such as trouble swallowing, dry mouth, loss of taste, neck stiffness, and thyroid problems.
What this means for patients
“Treatment for head and neck cancer can be quite grueling, so it’s very encouraging to see we can safely dial back treatment for patients with less aggressive disease and an overall good prognosis, particularly for young patients who have many years to deal with long-term side effects,” said lead study author Anthony Cmelak, MD, a professor of radiation oncology at the Vanderbilt-Ingram Cancer Center in Nashville, TN. “However, we need longer follow up, as well as confirmatory phase III data, before we can recommend applying this strategy in practice.” According to Dr. Cmelak, lower-dose IMRT is not suitable for patients with HPV-negative disease or larger tumors.
Questions to ask your doctor
- What type of head and neck cancer do I have?
- Is it important to find out if my tumor was caused by HPV? Why?
- Will my treatment plan include radiation therapy? Will radiation therapy be combined with chemotherapy?
- What dose and schedule do you recommend? Why?
- What are the possible side effects of my treatment plan, both in the short term and the long term? How can these be managed?
- Should I see a dentist before starting treatment?