The incidence of hyperthyroidism in patients with thyroid cancer in an area of iodine deficiency.

BACKGROUND

The incidence of hyperthyroidism among thyroid malignancy varies greatly depending on the geographical area and iodine intake. The aim of the study was to evaluate the association of hyperthyroidism and thyroid cancer (TC) in an iodine deficient area.

PATIENTS AND METHODS

Medical records of 422 patients who underwent operation for TC between 1992 and 2000 in Ankara Oncology Hospital were reviewed. The characteristics of TC patients with hyperthyroidism were analyzed in respect to gender, age, histopathological type, thyroid function status, tumor size, extrathyroidal invasion, local recurrences, distant metastasis, AMES and MACIS scoring.

RESULTS

In the present patient series, among 422 patients with TC, hyperthyroidism was found in 12 patients (2.8%). None of the patients had Graves' disease. Of 12 patients with hyperthyroidism, 9 patients had papillary carcinoma, 1 patient had follicular carcinoma and 2 patients had follicular variant of papillary carcinoma. The tumor was in the active nodule in 5 patients.

CONCLUSION

The existence of hyperthyroidism among patients with differentiated TC is a clinical entity. Patients with hyperthyroidism and nodules require a careful approach in order to establish or exclude the possibility of TC especially in formerly iodine deficient areas.