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

## TL;DR

About half of patients who undergo laryngectomy develop hypothyroidism, with risk factors like hemithyroidectomy and radiotherapy identified.

## Contribution

This study provides a systematic review and meta-analysis to quantify hypothyroidism risk and suggest preventative strategies after laryngectomy.

## Key findings

- The overall incidence of hypothyroidism after laryngectomy is 50%.
- Hemithyroidectomy, radiotherapy, and neck dissection are significant risk factors.
- Preventative measures include preserving thyroid blood supply and monitoring thyroid function.

## Abstract

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.

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.

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.

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.