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. Between 2006 and 2007, 84% of base of tongue cancer cases in Stockholm were HPV-positive. The objective of this study was to assess the impact of HPV status on prognosis for base of tongue cancer patients. One-hundred and nine patients were diagnosed with base of tongue cancer between 1998 and 2007 in Stockholm County and 95 paraffin-embedded diagnostic tumor biopsies were obtained and tested for HPV by PCR. Eighty-seven patients had available biopsies, were treated with intention to cure and could be included in the survival analysis. 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. In total 68 (78%) tumor biopsies from the 87 included patients were HPV DNA positive. Kaplan-Meier estimates showed that the overall survival for patients with HPV-positive cancer was significantly better (p = 0.0004), (log-rank test) than that of patients with HPV-negative cancer. Patients with HPV-positive tumors also had significantly better disease-free survival (p = 0.0008), (log-rank test) than those with HPV-negative tumors. These results further strengthen the option to consider HPV-status when planning prospective studies on treatment for base of tongue cancer.
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