Thyroid disease following irradiation for benign conditions

Area of Science:

• Endocrinology
• Oncology
• Surgical Pathology

Background:

• Prior irradiation to the head and neck for benign conditions is a known risk factor for thyroid abnormalities.
• Iodine-131 and external beam radiation increase the risk of thyroid cancer and benign thyroid diseases.

Purpose of the Study:

• To evaluate the incidence of thyroid abnormalities, particularly carcinoma, in patients with a history of head and neck irradiation for benign conditions.
• To compare the diagnostic accuracy of physical examination (palpation) versus thyroid isotope scanning in detecting thyroid carcinoma in this patient cohort.

Main Methods:

• Retrospective review of 125 patients who underwent thyroidectomy between 1967 and 1976.
• Analysis of patient history, palpable findings, thyroid isotope scan results, and histopathological examination of resected thyroid specimens.

Main Results:

• 124 out of 125 patients had a palpable thyroid abnormality.
• Thyroid carcinoma was diagnosed in 42 patients (33.6%), with 9 of these having nodal metastases.
• Physical examination (palpation) demonstrated higher accuracy in detecting carcinoma compared to thyroid isotope scans.
• Irradiation thyroiditis was identified in 50% of the resected specimens.

Conclusions:

• Patients with a history of head and neck irradiation for benign conditions have a significant risk of developing thyroid abnormalities, including carcinoma.
• Clinical palpation is a crucial diagnostic tool for identifying thyroid nodules in irradiated patients and is superior to isotope scanning for detecting malignancy.
• The high prevalence of irradiation thyroiditis underscores the impact of radiation on thyroid tissue.