Prevalence of thyroid cancer in Graves' disease: a retrospective study of a cohort of 103 patients treated surgically.
BACKGROUND: Thyroid nodules in patients with Graves' disease (GD) are common, and the incidence of coexisting thyroid carcinoma is a much debated subject, which is addressed in this study. METHODS: In order to determine the incidence rate of coexisting malignancy, a retrospective study was conducted on 103 patients who underwent surgery for GD between 1990 and 2000 at the Cliniques Universitaires Saint-Luc in Brussels, Belgium. The patients were classified into groups. Those in group I had a solitary palpable nodule (4.9%), those in group II multiple palpable nodules (12.6%), group IIIa had nodule(s) revealed by imaging techniques (incidentalomas: 17.5%), and group IIIb had diffuse non-nodular goiter (65%). RESULTS: Patients with nodules (groups I, II, and IIIa) were found to have significantly more thyroid carcinomas than those with diffuse non-nodular goiters (P=0.02), and the rate of malignancy was significantly increased when the nodules were palpable (groups I and II; P=0.03). Eight patients (7.8%) were diagnosed as having coexisting carcinomas, all but one being microcarcinomas. CONCLUSIONS: Well-differentiated papillary carcinomas are found to coexist with GD surgically treated (7.8%) and occur most frequently in GD with palpable nodular lesions (35%). Even though the majority (88%) of coexisting carcinomas are microcarcinomas, the presence of palpable nodules justifies further evaluation and follow-up.