Human papillomavirus (HPV) DNA in tonsillar cancer: clinical correlates, risk of relapse, and survival

Human papillomavirus (HPV) is more commonly found in tonsillar cancer than in other head and neck cancers. The importance of HPV status in tonsillar cancer for prognosis remains unclear. The aim of the present study was to investigate the frequency of HPV in tonsillar cancer and to correlate the presence of HPV with tumor stage, nodal status, grade of differentiation, risk of relapse, and survival. HPV DNA and HPV type were determined, using PCR, in pre-treatment biopsies from 60 cases of primary tonsillar cancer. All patients had undergone full-dose radiotherapy, 45% as the only treatment modality, and 55% in combination with surgery. HPV 16 was detected in 43% (26/60) of the cancers including 1 double infection of both HPV 16 and HPV 33. Patients with HPV(+) tonsillar cancer showed less risk of relapse within 3 years after diagnosis, with a better odds ratio of 4.18 as compared with HPV(-) patients (p = 0. 025). Furthermore, cause specific survival was significantly (p = 0. 047) better in patients with HPV(+) tonsillar carcinomas. At 3 years after diagnosis the survival rate was 65.3% in the HPV(+) group and 31.5% in the HPV(-) group, and at 5 years the survival rate was 53. 5% and 31.5%, respectively. The better outcome for patients with HPV(+) tonsillar cancer was independent of TNM stage, nodal status, gender and age. These results indicate that HPV status is a significantly favorable prognostic factor in tonsillar cancer and may be used as a marker in order to optimize the treatment of patients with this type of cancer.