Studies have shown higher survival rates for people with head and neck cancers that test positive for HPV when they are treated with systemic chemotherapy and radiation therapy. Now a new study suggests outcomes are also better when radiation therapy is combined with cetuximab, a targeted therapy. The data will be presented at the annual meeting of the American Society for Radiation Oncology, October 31st through November 4th in San Diego.
The study, conducted at Georgetown Lombardi Comprehensive Cancer Center, analyzed tumors from sequentially treated patients between 2007 and 2009 with head and neck squamous cell carcinoma that were treated with cetuximab and intensity-modulated radiation therapy (IMRT). Of these patients, six had stage III disease and 14 had stage IVa disease. The median age was 63 (age ranged from 31 to 78). The patients received IMRT for seven to eight weeks (media dose was 72.0 Gy). Cetuximab was given for a media of seven cycles. Primary tumor sites included oral cavity (1), oropharynx (12), hypopharynx (1), larynx (5), and with one site unknown.
After a median follow up of 19 months, four patients had died and 12 patients had disease progression.
"We found a statistically significant higher progression free survival rates when comparing the outcomes of patients with HPV-positive tumors to those with HPV-negative tumors," explains Keith Unger, MD, lead author of the study.
One-year progression free survival rates were 100 percent for those with HPV-positive tumors and 31 percent for those who were HPV negative. Two year progression free survival rates were 60 percent for those with HPV compared to 23 percent for those with HPV negative tumors (p=0.05).
While not statistically significant, researchers observed a trend in improved overall survival. One-year overall survival rates were 100 percent for those with HPV-positive tumors versus 83 percent in HPV-negative tumors. Two-year survival rates were 100 percent for HPV-positive tumors compared to 71 percent for HPV negative tumors (p=0.12).
"We found no correlation between overall survival or progression free survival and stage, nodal status, primary site, or the duration of radiotherapy," Unger concludes.