Prevalence of synchronous bilateral tonsil squamous cell carcinoma: A retrospective study

The prevalence of synchronous bilateral tonsil cancer remains unexplored. To date, only 38 cases have been described in the literature. With an aim to substantiate the Danish recommendation of performing bilateral tonsillectomy in patients with suspected or proven tonsil cancer and in patients with cervical carcinoma metastasis from an unknown primary tumour, this study was undertaken to determine the prevalence of synchronous bilateral tonsil cancer.

A retrospective review of all patients diagnosed with tonsil cancer in the period 2000-2015, Aarhus University Hospital, Denmark, was performed.

Seven of 211 (3.3%) consecutive patients with tonsil cancer, who had undergone bilateral tonsillectomy (n = 180) or unilateral tonsillectomy (clinically normal side) combined with contralateral tonsil biopsy (side with suspected cancer) (n = 31), had synchronous bilateral tonsil cancer. Furthermore, dysplasia was found in the contralateral tonsil in two patients with unilateral tonsil cancer. Four of 171 (2.3%) patients with suspected unilateral tonsillar cancer had additional contralateral tonsil cancer. Three of 34 (8.8%) patients without clinical signs of tonsillar malignancy on any side (32 patients with carcinoma of unknown primary) had synchronous bilateral tonsil cancer. In none of the patients were bilateral tonsil cancer suspected. Patients with unilateral vs synchronous bilateral tonsil cancer had similar clinical and tumour characteristics.

Knowledge on additional contralateral synchronous tonsil cancer is crucial for avoidance of early recurrence of oropharyngeal cancer in patients with tonsil cancer. Based on our findings, we recommend bilateral tonsillectomy in all patients with suspected or proven tonsil cancer and carcinoma of unknown primary.