The prevalence of hypothyroidism after treatment for laryngeal and hypopharyngeal carcinomas: are autoantibodies of influence?

CONCLUSIONS

The incidence rate of hypothyroidism after treatment for laryngeal and hypopharyngeal cancer is high, especially after combination treatment. An association between hypothyroidism and autoantibodies was found.

OBJECTIVES

The incidences of hypothyroidism and autoantibodies were assessed retrospectively in 156 patients with laryngeal and hypopharyngeal carcinoma who were treated with surgery and/or radiotherapy between 1977 and 2002.

PATIENTS AND METHODS

Patients treated for T2-T4 carcinoma or a recurrence after T1 who visited the outpatient clinic for their regular follow-up visit were included. All patients were evaluated for the development of hypothyroidism, defined as increased thyroid-stimulating hormone level (>4.5 mU/L) and the presence of autoantibodies. A questionnaire regarding symptoms was administered.

RESULTS

The prevalence of undiagnosed hypothyroidism following treatment of laryngeal carcinoma was 28.2%: 18.6% subclinical hypothyroidism and 9.6% clinical hypothyroidism. The prevalence of circulating antithyroid antibodies (anti-thyreoperoxidase and/or anti-thyreoglobulin) was 10.5%. Univariate analysis showed that patients with laryngectomy, hemithyroidectomy, ipsilateral neck dissection and autoantibodies had a higher risk of hypothyroidism. The combination of surgery and radiotherapy increased the risk. Symptoms such as weight gain and cold intolerance were significantly associated with hypothyroidism. Multivariate analysis showed hemithyroidectomy, autoantibodies, weight gain and cold intolerance to be prognostic factors for the development of hypothyroidism.