Halving radiation therapy for HPV-related throat cancer offers fewer side effects, similar outcomes
Mayo Clinic researchers have found that a 50 percent reduction in the intensity and dose of radiation therapy for patients with HPV-related throat cancer reduced side effects with no loss in survival and no decrease in cure rates. Results of a phase II study were presented today at the 59th Annual Meeting of the American Society for Radiation Oncology in San Diego by Daniel Ma, M.D. a radiation oncologist at Mayo Clinic.
"A common approach for treating HPV-related throat cancer is a combination of surgery followed by daily radiation therapy for six to 6½ weeks," says Dr. Ma. "However, the radiation treatment can cause a high degree of side effects, including altered taste, difficulty swallowing, dry mouth, stiff neck and damage to the jaw bone." Dr. Ma says that patients with HPV-related throat cancer tend to be young and, once treated, are likely to live a long time with possibly life-altering side effects from the standard treatment. "The goal of our trial was to see if an aggressive reduction of radiation therapy (two weeks of radiation twice daily) could maintain excellent cure rates, while significantly reducing posttreatment side effects, improving quality of life and lowering treatment costs."
Researchers followed 80 patients with HPV-related oropharyngeal squamous cell cancer with no evidence of residual disease following surgery and a smoking history of 10 or fewer pack years. That's the number of years smoking multiplied by the average packs of cigarettes smoked per day.
At two years following the aggressively de-escalated treatment, the rate of tumor control in the oropharynx (throat) and surrounding region was 95 percent. Of the 80 patients in the trial, only three experienced a local cancer recurrence. One patient experienced a regional cancer recurrence. Patient quality of life largely improved or did not change following treatment, except for some dry mouth.
"Patients in our trial had a very dramatic reduction in side effects, compared with standard treatment," says Dr. Ma. "For example, no patient in our trial needed a feeding tube placed during dose-reduced treatment; whereas, close to a third of patients had feeding tubes placed with traditional radiation therapy doses on other recent clinical trials." Dr. Ma says the reduction in side effects did not lead to any reduction in cure rate, as survival rates were similar to traditional survival rates for HPV-related throat cancer.