Thyroid Gland Involvement and the Efficiency of Thyroidectomy in Patients Having Larynx and Hypopharyngeal Cancers Treated with Surgery

Background: Thyroid gland involvement and invasion during larynx and hypopharynx cancers is rare, but due to the anatomical closeness of the thyroid gland and the larynx, it could occur through local invasion. Thyroidectomy is usually performed in patients with thyroid gland involvement having larynx and hypopharyngeal cancers. A lot of controversies exist regarding the thyroid gland involvement and efficiency of a different kind of thyroidectomy intraoperatively in these types of cancers. Objectives: Thus, elucidating the exact role of thyroidectomy, its efficiency, and parameters associated with thyroid gland involvement is critical in treating the patients with the larynx and hypopharyngeal cancers. Methods: In this retrospective study, the medical records of 117 patients admitted to Loghman Hakim Hospital from 2001 to 2015 with laryngeal and hypopharyngeal carcinoma, who underwent laryngectomy with or without thyroidectomy as a primary treatment of cancer, were evaluated. Several parameters, including gender, prevalence, location of the thyroid gland and lymph node involvement, the exact type of malignancy, differentiation stage of the tumor cells, the exact method of thyroidectomy, thyroid function, and its post-surgical cancer recurrence were assessed. Results: The prevalence of laryngeal cancers was significantly higher in males than females and most of the malignancies were squamous cell carcinoma (SCC). The location of the malignancy was mostly at supraglottis, glottis, transglottis, and subglottis, respectively. The rate of thyroid gland involvement was approximately 11.96%. Lobectomy was performed in 57.14 %, total thyroidectomy was performed in 35.71 %, and in 7.14% of the patients, and thyroidectomy was not performed. After the initial surgery, out of 11.96% of all patients with thyroid gland involvement, 28.5% had a recurrence of the thyroid gland. Only 21% of the patients with thyroid gland involvement had hypothyroidism after the surgery. Conclusions: The rate of thyroid gland involvement in the pathology report after surgery was approximately 3.41% of the thyroid gland involvement, which is low. We concluded that thyroidectomy is a very efficient way, but it should be limited to cases of subglottic or transglobic involvement or in cases of bilateral tumors, high staging, post-cricoid involvement, and clear radiological evidence or in the event of muscle involvement.