SAI ,IVARY GLANDS - RADIOACTIVE IODINE MARCH 1998 Following surgery, therapeutic management of most thyroid cancers includes radioactive iodine (131I). This radioisotope is used because of its affinity for thyroid tissue. Initially, 131I is employed in diagnostic scanning to uncover the presence of normal thyroid and locally malignant and/or metastic thyroid cancer left behind after thyroidectomy. Subsequently, successful treatment of thyroid cancer demands 131I destruction of any residual normal thyroid tissue. Because patients require longitudinal monitoring by radioactive iodine, such an approach avoids competition for the 131I between normal and malignant tissue, thus permitting enhanced 131I uptake by malignant areas. After diagnostic scanning and thyroid ablation with 131I, eradication of residual carcinoma in the thyroid bed or in metastatic locations is accomplished with elevated dosages of 131I (100-250 millicuries). Unfortunately, normal salivary glands also selectively concentrate the 131I and thereby suffer some of the sequelae of radiation. Compared to mucous cells, serous cells have a greater ability to concentrate the 131I. Consequently, the serous parotid gland will demonstrate a more intense radiation sialadenitis than the mucous cell-containing salivary glands. Obviously, the effect is dose related. Transient salivary gland swelling and pain, mostly involving the parotid, often rapidly develop following therapeutic dosages of 131I. Sialogogues (lemon drops) can be used to hasten the 131I transit time thru the salivary gland and decrease the effect of the ionizing radiation on the cell's genetic structure. Regardless, manifestations of injury may become apparent in succeeding cell generations with severe objective and subjective symptoms evolving. Persistent sialadenitis is not an unexpected complication. The chronic parotitis, with intermittent episodes of pain and swelling resulting from 131I injury, may be unilateral or bilateral. Salivary volume decreases. Permanent xerostomia with a caries increase can occur. Infection ensues from an ascending ductal infection facilitated by a diminished ductal ravage and an impaired gland. Salivary chemistry, as determined by the Salivary Gland Center (SGC), is altered and reflects the existence of an inflammatory process. A small increase in salivary tumors has also been reported. Treatment? Salivary secretions can be increased with sugarless lemon candy and gum or pilocarpine (Salagen â). Artificial saliva has not met with patient satisfaction. Aggressive fluoride therapy and oral hygiene impede caries from salivary loss. The Salivary Gland Center (SGC) was developed because a void existed in the diagnostic and comprehensive care of patients with salivary gland problems and/or secretory dysfunction. Since the diversity of these salivary conditions presents challenges to the clinician, the SGC is available for referrals. Louis Mandel, DDS Director, Salivary Gland Center (212) 305-9982