Two cases of lymphoma of the parotid gland following ablative radioiodine therapy for thyroid carcinoma

Mucoepidermoid Parotid Gland Tumor Found on Follow-up Radioiodine Scan for Differentiated Papillary Thyroid Cancer

This report presents a case of focal uptake in the right parotid gland found on a follow-up whole-body radioiodine scan 1 y after successful ablation of differentiated papillary thyroid carcinoma. After the parotid tumor had been excised, it was proven histopathologically to be a low-grade mucoepidermoid tumor. This case illustrates a ¹³¹I focus that was false-positive for thyroid carcinoma. The short period between radioiodine treatment and development of this parotid tumor creates doubt about a causal relationship. Induction of salivary gland tumors by radiation has been reported primarily in the setting of external radiotherapy. In the large volume of thyroid carcinoma patients treated with radioiodine across the world, such an occurrence has been rare.

RETRACTED ARTICLE: Radiation sialadenitis induced by high-dose radioactive iodine therapy

Radioactive iodine ((131)I) is accumulated in the thyroid tissue and plays an important role in the treatment of differentiated papillary and follicular cancers after thyroidectomy. Simultaneously, (131)I is concentrated in the salivary glands and secreted into the saliva. Dose-related damage to the salivary parenchyma results from the (131)I irradiation. Salivary gland swelling and pain, usually involving the parotid, can be seen. The symptoms may develop immediately after a therapeutic dose of (131)I and/or months later and progress in intensity with time. In conjunction with the radiation sialadenitis, secondary complications reported include xerostomia, taste alterations, infection, increases in caries, facial nerve involvement, candidiasis, and neoplasia. Prevention of (131)I sialadenitis may involve the use of sialogogic agents to hasten the transit time of the radioactive iodine through the salivary glands. However, studies are not available to delineate the efficacy of this approach. Treatment of the varied complications that may develop encompass numerous approaches and include gland massage, sialogogic agents, duct probing, antibiotics, mouthwashes, good oral hygiene, and adequate hydration. Recently interventional sialoendoscopy has been introduced an effective tool for the management of patients with (131)I-induced sialadenitis that is unresponsive to medical treatment.

Radioactive iodine and the salivary glands

Radioactive iodine ((131)I) targets the thyroid gland and has been proven to play an effective role in the treatment of differentiated papillary and follicular cancers. Simultaneously, this radioisotope hones in on the salivary glands where it is concentrated and secreted into the saliva. Dose related damage to the salivary parenchyma results from the (131)I irradiation. Salivary gland swelling and pain, usually involving the parotid, can be seen. The symptoms may develop immediately after a therapeutic dose of (131)I and/or months later and progress in intensity with time. In conjunction with the radiation sialadenitis, secondary complications reported include xerostomia, taste alterations, infection, increases in caries, facial nerve involvement, stomatitis, candidiasis, and neoplasia. Prevention of the (131)I sialadenitis may involve the use of sialogogic agents to hasten the transit time of the radioactive iodine through the salivary glands. However, studies are not available to delineate the efficacy of this approach. Recently, amifostine has been advocated to prevent the effects of irradiation. Treatment of the varied complications that may develop encompass numerous approaches and include gland massage, sialogogic agents, duct probing, antibiotics, mouthwashes, good oral hygiene, and adequate hydration.

A case report of mucoepidermoid carcinoma of the parotid gland developing after radioiodine therapy for thyroid carcinoma

This is a report on a 19-year-old female who developed a low grade T2 N0 M0 mucoepidermoid carcinoma of the right parotid gland 3 years and 5 months after the post-operative treatment of 100 mCi of radioactive iodine (131I) for a papillary thyroid carcinoma. The parotid tumour appeared during the patient's pregnancy. There are few reports of salivary gland cancer developing after radioiodine therapy for thyroid carcinoma and it is hoped that this report may stimulate others to investigate this association further in order to clarify the risk of secondary malignancies after radioiodine therapy.

In situ breast carcinoma after treatment during adolescence for thyroid cancer with radioiodine

We reviewed the courses of patients treated during childhood or adolescence for thyroid cancer to estimate the frequency of, and to identify possible risk factors for, the occurrence of second malignant tumors in this population. We identified all patients treated for thyroid cancer in a cohort of 1,406 pediatric cancer patients who were diagnosed prior to 20 years of age during the period January 1, 1960 through December 31, 1988 and who were treated at Roswell Park Cancer Institute. Twelve patients were treated for thyroid cancer, of whom nine were women. In situ breast carcinoma was diagnosed 25 and 26 years after diagnosis of thyroid cancer in two of four women treated with radioiodine. No new cancers were diagnosed in the five women treated with thyroidectomy only. Two of four women treated for thyroid cancer during adolescence with radioiodine, which is concentrated in the breast as well as other organs, developed in situ breast carcinoma. Review of a large cohort of adolescent female thyroid cancer patients treated with radioiodine is necessary to provide an accurate estimate of their risk of developing breast cancer. These patients must remain under medical surveillance throughout their lifetimes to facilitate prompt diagnosis of and early intervention for new conditions, such as the occurrence of breast cancer.

Radionuclide therapy revisited

Apart from its use in endocrinology and rheumatology, therapeutic nuclear medicine is developing rapidly as an additional treatment modality in oncology. Many different specific tumour-seeking radiopharmaceuticals are being applied both for diagnostic scintigraphy and treatment, using multiple routes and mechanisms to target radionuclides at tumours. After a brief introduction of some basic principles of radionuclide targeting, the therapeutic radiopharmaceuticals available are reviewed according to the accumulation site in relation to the cell nucleus; the results of their current clinical use for therapy are also reviewed. The response observed to a number of these applications, the non-invasiveness of the procedure and the relative lack of toxicity and late effects in comparison with chemotherapy and external beam radiotherapy make radionuclide therapy an attractive and realistic alternative in the management of malignant disease, as well as in the treatment of a few benign disorders.

Salivary gland tumors and previous radiotherapy to the head or neck. Report of a clinical series

To estimate what proportion of patients with newly diagnosed salivary gland tumors may have radiation-related disease, we interviewed all 275 patients in a surgical practice who had salivary gland resections during an 8 year period. Patients were asked about previous radiation treatment to the head and neck. Thirty-one patients (11 percent) had both an incident salivary gland tumor and a history of significant exposure. Four of these patients (13 percent) had multiple primary tumors of the salivary glands. The implications and generalizability of these findings have been discussed herein.