Hypothyroidism in patients treated with total laryngectomy. A multivariate study.

One of the complications of the treatment of head and neck carcinoma patients is hypothyroidism. The objective of our study was to quantify the prevalence of hypothyroidism in patients with laryngeal or hypopharyngeal cancer treated with a total laryngectomy and to evaluate the importance of different variables in the appearance of hypothyroidism in this group of patients. A transversal study in 182 patients treated with total laryngectomy between 1986 and 1998 was carried out. TSH and FT4 were determined in all patients. Hypothyroidism was classified as subclinical (increased TSH and normal T4 levels) and clinical (increased TSH and decreased T4 levels). Univariate and multivariate analysis was carried out to examine the relationship between hypothyroidism and different variables. Our results showed that the prevalence of hypothyroidism in our group of patients was 52% (27% subclinical and 25% clinical). Sex, initial extension of the tumour, hemithyroidectomy, use of chemotherapy and radiotherapy were variables associated with the appearance of hypothyroidism in the univariate analysis (P < 0.05). When all these variables were included in a multivariate study, only hemithyroidectomy (RR 3,6; CI 95% 1,7-7,2) and combined treatment with radiotherapy (RR 3,4; CI 95% 1,2-9,6) appeared as prognostic factors. In conclusion, hypothyroidism is a frequent complication in patients treated with a total laryngectomy (52%), especially when this treatment includes hemithyroidectomy and/or radiotherapy. We consider that it is important to check the thyroid function periodically in these patients to obtain early diagnosis and appropriate treatment.