Does thyroid sparing total laryngectomy decrease the risk of hypothyroidism?

Viljoen, Gerrit

Does thyroid sparing total laryngectomy decrease the risk of hypothyroidism?

Master Thesis

2022

Abstract

Introduction Thyroid lobectomy is recommended with total laryngectomy for laryngeal cancer in the National Comprehensive Cancer Network (NCCN) guidelines. However, it is associated with a 32-89% risk of hypothyroidism, which represents a problem especially for patients without access to thyroid hormone monitoring and replacement. Sparing the thyroid gland does not compromise oncological control if thyroid lobectomy is reserved for intraoperative evidence of extra laryngeal tumor extension abutting or invading the thyroid gland, or when there is need to resect level 6 lymph nodes with subglottic and pyriform fossa involvement. However, there is limited evidence about to what extent hypothyroidism is avoided if the thyroid gland is completely spared compared to hemithyroidectomy in the setting of a total laryngectomy. Aims The aims of the study were to determine whether preserving the whole thyroid, compared to a single lobe, does indeed significantly lower the incidence of hypothyroidism in the setting of a total laryngectomy with or without adjuvant radiotherapy. Method A retrospective study was done at Groote Schuur Hospital in Cape Town, South Africa. The thyroid function of patients who had undergone thyroid sparing total laryngectomy with or without radiotherapy was determined and compared to those who underwent hemithyroidectomy. Results Eighty-four patients met the inclusion criteria. The overall incidence of hypothyroidism was 45.2%. The incidence of hypothyroidism was significantly reduced in patients who underwent thyroid sparing total laryngectomy compared to hemithyroidectomy (p=0.037). Adjuvant radiotherapy was associated with a higher incidence of hypothyroidism (p=0.001). Conclusion Thyroid preserving laryngectomy should be advocated in carefully selected patients with advanced laryngeal carcinoma as it reduces the incidence of hypothyroidism.