Pretreatment prevalence of hypothyroidism in patients with head and neck carcinoma

BACKGROUND. Hypothyroidism in the normal population age > 60 years is encou ntered in the range of 0.5-5% clinically, and 5-20% have subclinical hypofu nction. Hypothyroidism is recognized as a common complication of treatment in patients with head and neck carcinoma (HNC) and is reported in up to 75% of patients who receive combined treatment. Surprisingly, base-line pretre atment measurements of thyroid function in large series of patients have no t been reported. METHODS. Serum thyroid- stimulating hormone, free T4, and total T3 levels w ere recorded in 110 patients with nonthyroid HNC prior to treatment in a pr ospective, controlled study. RESULTS. The mean patient age ( standard deviation) was 65 years +/- 13.8 y ears, and 82% of patients had squamous cell carcinoma. A diagnosis of hypot hyroidism already was established in 4.5% of patients, and subclinical hypo thyroidism was discovered in an additional 6.4% of patients. Sixteen patien ts had other equivocal anomalies in thyroid function and were referred for further endocrine evaluation. No patients with formerly unrecognized clinic al hypothyroidism were found. CONCLUSIONS. Hypothyroidism in patients with head and neck carcinoma in Isr ael corresponds with the reported incidence in the general population. Hypo thyroidism after treatment for head and neck carcinoma stems from the effec ts of treatment. The need for pretreatment evaluation of thyroid function s hould be considered. (C) 2001 American Cancer Society.