Incidence, risk factors and prevention of hypothyroidism following laryngectomy: a systematic review and meta-analysis.

Introduction: Hypothyroidism following laryngectomy is a well-recognised complication. The symptoms are multisystemic and can cause significant morbidity in patients. We aim to characterise the incidence of hypothyroidism following laryngectomy, and identify risk factors and preventative measures.

Methods: A systematic search of EMBASE and PubMed was performed. We appraised relevant articles as per the predefined eligibility criteria. A quality assessment of the included studies was done. A meta-analysis was performed to evaluate the association between reported risk factors and hypothyroidism.

Results: Forty articles were included. This encompassed a total of 3,061 patients with a median age of 61 years. Overall incidence of hypothyroidism was 50% (interquartile range: 38.3-75.7). The following factors were significantly associated with hypothyroidism: hemithyroidectomy, odds ratio (OR) 4.84 (95% confidence interval [CI] 3.46-6.77); radiotherapy, OR 4.4 (95% CI 2.29-8.43); and neck dissection, OR 2.63 (95% CI 1.56-4.44). Age, sex, chemotherapy and tumour stage were not significant in the meta-analysis. Preventative measures were based on reducing the extent of thyroid dissection, attention to the preservation of blood supply, and pre- and postoperative thyroid function test monitoring.

Conclusions: A significant proportion of patients develop hypothyroidism following laryngectomy. Utilising known risk factors may direct a preventative measure. Further well-designed multicentre observational studies exploring preventative measures including reducing hemithyroidectomy, monitoring intervals of thyroid function and utility of routine thyroxine replacement are required.