Incidence of thyroid gland invasion in advanced laryngeal cancers and its impact on disease-specific survival; a retrospective review at a tertiary care center.

Background: Incidence of thyroid gland invasion in advanced laryngeal cancers is low. Ipsilateral or total thyroidectomy along with total laryngectomy has been controversial and there has been no consensus over the management of thyroid gland in advanced laryngeal cancers.Objective: To determine the frequency of thyroid gland invasion in locally advanced laryngeal squamous cell carcinoma and the risk factors associated with it.Material and methods: A retrospective review of patients with laryngeal squamous cell carcinoma operated at our center between January 2011 and December 2018 was carried out. Patients undergoing upfront or salvage laryngectomy with or without neck dissection along with hemi or total thyroidectomy were included. Histopathology reports were reviewed to record the involvement of thyroid gland.Results: Invasion of thyroid gland by squamous cell carcinoma larynx was seen in 10 (10.9%) patients out of 92. All of the cases showed direct extension of the tumor. Trans-glottic, subglottic, and tumors with extra laryngeal spread were found to be significantly associated with thyroid gland invasion. Patients with thyroid gland invasion showed higher rate recurrence.Conclusion and significance: Incidence of thyroid gland invasion in squamous cell carcinoma larynx is low, allowing us not to address thyroid routinely in patients undergoing total laryngectomy for laryngeal carcinoma.