Predictors of thyroid gland involvement in hypopharyngeal squamous cell carcinoma

Decision to perform concurrent ipsilateral thyroidectomy on patients with hypopharyngeal cancer is important, and unnecessary thyroidectomy should be avoided if oncologically feasible. We hypothesized that concurrent ipsilateral thyroidectomy is not routinely required to prevent occult metastasis. This study aimed to determine the prevalence of histological thyroid invasion in patients with hypopharyngeal cancer, and to refine the indications for prophylactic ipsilateral thyroidectomy in patients with hypopharyngeal cancer.

A retrospective review of the medical records from the Department of Otolaryngology at Yonsei University College of Medicine was conducted from January 1994 to December 2009. A total of 49 patients underwent laryngopharyngectomy with thyroidectomy as a primary treatment of hypopharyngeal cancer.

The incidence of thyroid gland involvement was 10.2%. The most common route of invasion was direct extension through the thyroid cartilage. Thyroid cartilage invasion (p=0.034) was the most significant factor associated with thyroid invasion. Disease-specific survival at 5 years was lower in patients with than without thyroid gland invasion (26.7% vs. 55.2%, respectively; p=0.032). Disease-free survival at 5 years was also lower in patients with than without thyroid gland invasion (20.0% vs. 52.1%, respectively; p=0.024).

Ipsilateral thyroidectomy in combination with total laryngopharyngectomy is indicated when invasion of the thyroid cartilage is suspected in patients with hypopharyngeal cancer.