Researchers at the University of North Carolina (UNC) Lineberger Comprehensive Cancer Center have found that HPV-positive (human papillomavirus) patients with oropharyngeal cancer of the back of the throat can be given lower treatment doses of chemotherapy and radiation successfully, leading to fewer side effects.
Previous research has shown that oropharyngeal cancer patients who are HPV-positive have higher response rates to radiation and chemotherapy and better prognoses than patients with HPV-negative cancer. In fact, 86% of a group of highly selected, favorable-risk HPV-positive patients were cancer-free after receiving the lower doses.
“We are probably over-treating these patients with the standard radiation and chemotherapy regiments,” said Bhishamjit S. Chera, MD, a UNC Lineberger member and associate professor at the UNC school of medicine department of radiation oncology. “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.”
The phase II clinical trial involved 43 patients who had favorable-risk, HPV- or p16-positive oropharyngeal squamous cell carcinoma and a minimal smoking history. They received weekly doses of 60 gray of radiation for 6 weeks and a 180-mg/m2dose of cisplatin. The standard treatment is 70 gray for 7 weeks and 300 mg/m2 of cisplatin. During treatment, patients saw lower acute side effects such as pain and nausea.
After limited neck surgery in the lymph node region and biopsies of the primary tumor sites, 37 of the 43 patients had no evidence of cancer. The other 6 patients had microscopic residual foci of unknown significance that was removed in the planned biopsy and limited neck dissection. At a follow-up, all 43 patients were alive with no cancer recurrence.
While these results are promising, the researchers said, additional studies of lower-dose radiation and chemotherapy regimens are needed. Funded by UNC and the University of Florida, this study was published in the International Journal of Radiation Oncology.