Need for thyroidectomy in patients treated with radioactive iodide for benign thyroid disease.

Introduction: Nodular toxic and non-toxic goitres are seen in approximately 15% of Danish women, and the pros and cons of thyroidectomy versus radioiodine (RI) therapy are often discussed. The purpose of this study was to evaluate the type and number of patients treated on the indication of hyperthyroidism or benign goitre who did not achieve a sufficient effect of RI therapy and therefore needed thyroidectomy.

Material and methods: Between 1 January 2003 and 1 January 2008, a total of 873 patients were treated with RI on the indication of benign thyroid disease at Herlev Hospital (Denmark). Data concerning these patients were listed consecutively in a database. The data were subsequently cross-checked with the Danish Thyroid Surgery Quality Register (THYKIR) which contains data on all patients treated with thyroid surgery at Danish departments of ear, nose and throat and head and neck surgery since 1 January 2001. Patient data were also cross-checked with the National Patient Register data. The unique Danish social security numbers were used to compare data.

Results: Among the 873 patients treated with RI, 36 were listed in the THYKIR database. Eleven of these had primary thyroid surgery and subsequently underwent RI treatment due to goitre recurrence. Twenty-five patients first received RI therapy and subsequently thyroidectomy due to persisting symptoms (17 had non-toxic goitre and compression symptoms (among these eight had a large goitre with a thyroid volume of > 100 ml (range 100-389 ml)), five had nodular toxic goitre and three had diffuse toxic goitre and continuing hyperthyroidism despite RI treatment. Thyroid surgery revealed a small (2-3 mm) cancer in two patients, both from the group of patients with nodular toxic goitre.

Conclusion: The effect of RI therapy sufficiently solved the problem (hyperthyroidism or goitre) and surgery was hence avoided in 848 of 873 (97%) patients. However, within the group of patients with nontoxic goitre, a subgroup of patients with large goitres seems to be resistant to RI treatment and does not achieve sufficient effect under the current RI therapy regime.

Funding: not relevant.

Trial registration: Danish Data Protection Agency (Datatilsynet) HEH.afd.O.750.86-7 and 2010-231-0068.