Invasion of the Thyroid Gland in Advanced Laryngeal and Hypopharyngeal Squamous Cell Carcinoma

Abstract

Objectives: (1) Evaluate the frequency of invasion of the thyroid gland in patients with laryngeal or hypopharyngeal squamous cell carcinoma (SCC) submitted to total laryngectomy (TL) or pharyngolaryngectomy (TPL) associated with thyroidectomy. (2) Determine whether clinico-pathological characteristics can predict glandular involvement. Methods: A retrospective study was conducted in an academically affiliated tertiary care referral center. Charts and anatomopathological reports of surgical specimens of 93 patients treated in the period from January 1998 to July 2013 were reviewed. All patients presented with laryngeal or hypopharyngeal SCC and underwent TL or TPL in association with thyroidectomy. Adjuvant therapy was indicated when tumor or neck conditions required it. Sociodemographic data, frequency of thyroid gland invasion, and other clinico-pathological variables were analyzed. Results: Tumor was staged as T2 in 10 patients, T3 in 26 patients, and T4 in 53 patients. Five patients had initial stage II and 88 had advanced stage III-IV disease. The overall frequency of invasion of the thyroid gland was 16.1%. Carcinomas that invaded the thyroid gland were more advanced ( P = .005) and more frequently staged as T4a ( P = .001). Glandular involvement was associated with invasion of the anterior commissure (odds ratio [OR] = 5.9; confidence interval [CI]–95% 1.2-27.7), subglottis (OR = 12.0; CI-95% 1.5-95.8), thyroid cartilage (OR = 4.2; CI-95% 1.1-16.1), and cricoid cartilage (OR = 18.7; CI-95% 5.0-70.2). Conclusions: Invasion of the thyroid gland is uncommon in the context of laryngopharyngeal SCC. Clinico-pathological features such as advanced tumors, T4a tumors, anterior commissure, subglottis, thyroid cartilage, and cricoid cartilage involvement are more associated with glandular invasion. Indications for thyroidectomy should be refined in order to reduce morbidity of the surgical treatment.