According to a presentation at the recent European Society for Radiotherapy and Oncology (ESTRO) meeting in Barcelona, Spain, oropharyngeal cancers in patients who are positive for the human papilloma virus (HPV) and who never smoked or were light smokers may be treated effectively with radiotherapy alone, potentially sparing these selected patients from additional chemotherapy and its toxicity.
In a retrospective analysis of 181 patients on the Danish Head and Neck Cancer Group database treated between 1992 and 2005 for advanced oropharyngeal cancer, HPV-positive patients had significantly improved local control, disease-specific survival, and overall survival at 5 years compared with HPV-negative patients. Analysis of smoking history showed that HPV-positive patients with a smoking history of less than 10 packyears (1 pack-year equals 20 cigarettes per day for 1 year) had improved outcomes compared with HPV-negative patients and those with a smoking history of more than 10 pack-years.
“This study is part of an ongoing debate about how to treat patients according to known prognostic factors, in this case, tumor HPV status and smoking history,” stated Pernille Lassen, a radiation oncology resident at Aarhus University Hospital, Aarhus, Denmark. “These findings confirm the highly significant independent influence of HPV status on tumor control and survival in advanced oropharyngeal cancer that is treated with radiotherapy alone, without chemotherapy. Our results suggest that use of radiotherapy alone may be a safe treatment strategy in patients who are light or nonsmokers, while sparing them the side effects associated with chemotherapy. However, it is still too early to select patients for a specific treatment based on these factors; we still need more data,” she stated, according to a press release from ESTRO.
All patients in the study received accelerated radiotherapy consisting of 6 fractions over 5 days along with nimorazole, a radiation sensitizer. No chemotherapy was used. Of the 181 patients, 103 (57%) were HPV positive. Tumor control was achieved in 81% of HPV-positive patients versus 48% of patients who were HPV negative. Five-year disease-specific survival was 90% versus 56%, respectively, and 5-year overall survival was 77% versus 38%, respectively.
When smoking history was accounted for, favorable outcomes were observed in HPV-positive light smokers or nonsmokers. For HPV-positive light smokers or nonsmokers versus HPV-positive heavy smokers, 5-year outcomes were as follows: tumor control at primary site, 91% versus 77%; disease-specific survival, 96% versus 81%; and overall survival, 90% versus 63%, respectively.
Seventy-six of the 78 HPV-negative patients were heavy smokers, and their outcome was significantly worse than HPV-positive patients, with a 5-year disease-specific survival of 50% to 52%.