Factors predicting survival outcomes for patients with HPV-positive base of tongue cancer.

Abstract

5575 Background: Base of tongue cancer is the second most common oropharyngeal cancer in Sweden. We have previously demonstrated that the incidence of base of tongue cancer is increasing in Sweden and the proportion of human papillomavirus (HPV) positive cancer has increased in Stockholm, Sweden. Aims: This study aims to assess the impact of HPV status on prognosis for base of tongue cancer patients. Methods: All patients diagnosed with base of tongue cancer between 1998 and 2007 in Stockholm County and treated with the intention to cure was included in the survival analysis. Pre-treatment biopsies were obtained and tested for HPV both by general HPV PCR and HPV-16/HPV-33 type specific PCR. Age, sex, TNM-stage, stage, treatment and survival were recorded from patient charts. Kaplan-Meier curves were used to present survival data. In multivariable analyses, a Cox proportional hazards model was used to adjust for covariates. Results: Eighty-seven patients had available biopsies, were treated with intention to cure and could be included in the survival analysis. In total 68 (78%) tumor biopsies from the 87 included patients was HPV DNA positive. Kaplan-Meier estimates showed that the overall as well as disease free survival for patients with HPV-positive cancer was significantly better, (log-rank test) than that of patients with HPV-negative cancer. Conclusions: Survival for patients with HPV-positive base of tongue cancer was improved, regardless of oncological treatment and despite the fact that these patients were higher staged and with higher frequency of nodal metastases. These results further strengthen the option to consider HPV-status when planning prospective studies on treatment for base of tongue cancer.