Characterization of Graves’ disease development after partial thyroidectomy for thyroid cancer

BACKGROUND: Graves’ disease (GD) is the most common cause of hyperthyroidism, and it rarely develops in patients who undergo partial thyroid removal for thyroid cancer. The present study characterized and analyzed the GD development mechanism after partial thyroidectomy for thyroid cancer and suggested optimized treatments for the condition. METHODS: A retrospective study from January 2013 to March 2017 was conducted in patients where GD occurred after partial thyroidectomy for thyroid cancer. Reviewed laboratory data included free 3,5,3'-triiodothyronine, free thyroxine, thyroid-stimulating hormone (TSH), thyroglobulin (Tg), anti-Tg antibody, anti-peroxidase antibody, and TSH receptor antibody levels. All laboratory indicators included preoperative and postoperative data. In addition, we collected patient neck ultrasound examination records and radioiodine (RAI) uptake test data. RESULTS: Among 5,600 patients diagnosed with GD, 5 (0.09%) met the inclusion criteria and were enrolled. Patient mean age was 47.4±9.6 years, and all were female with a papillary thyroid carcinoma stage I diagnosis. The interval between partial thyroidectomy and hyperthyroidism onset ranged from 2 to 25 months. We proposed possible mechanisms for this medical condition and identified several factors accelerating the disease course. To treat GD, a low RAI (30 mCi) dose was prescribed to patients. All exhibited hypothyroidism at a 3- or 6-month follow-up, with stable clinical status at 1-year follow-up. CONCLUSIONS: GD rarely develops after partial thyroidectomy for thyroid cancer. We recommend a low RAI dose to manage GD and ablate the remnants of thyroid cancer.