Late side effects of radioactive iodine on salivary gland function in patients with thyroid cancer.

BACKGROUND The purpose of this study was to assess the late side effects of radioiodine therapy (RIT) on salivary gland function. One hundred eighty two patients were evaluated. METHODS Assessment of salivary gland function was performed with salivary gland scintigraphy (SGS), sialometry, and subjective open questions to determine common side effects of RIT on salivary gland function. RESULTS RIT had a strong association with decreased elimination counts by SGS. Patient age was the only variable associated with sialometry; age and the use of xerostomic drugs were strongly associated with decreased mean values of salivary flow. Dysphagia was strongly associated with RIT. Using multiple logistic regression analysis, age was determined to be an important factor associated with salivary gland dysfunction, and RIT was associated with impairment of saliva excretion. CONCLUSION These results show that patients subjected to RIT have more difficulty in draining saliva, mainly from the parotid glands, which is associated with clinical dysphagia in this subset of patients.