Efficacy of fixed high dose (30 mCi) Iodine-131 therapy for solitary toxic thyroid nodule

Objectives To determine the effectiveness of a fixed high dose (30 mCi) Iodine-131 therapy for treatment of solitary toxic thyroid nodules.

Methods Thirty seven seven consecutive patients, presenting with hyperthyroidism, whose 99mTcO4 thyroid scan revealed solitary thyroid nodules, and who had undergone high dose (30 mCi) Iodine-131 therapy, with follow-up of a minimum one year, were recruited for this retrospective study. The therapies had been done at our institution from January 2008 to December 2013. The Technetium Thyroid uptake pre-treatment was noted for all patients. The biochemical status, freeT4 and TSH, at the end of one year was noted.

Results The Technetium thyroid uptake ranged from 3.7% to 10.7%, with a mean of 6.1%. Thirty (81.1%) of the patients were biochemically euthyroid at the end of one year. Four patients (10.8%) had documented hypothyroidism between seven and eleven months after the therapy and were on thyroxine supplementation. Three patients (8.1%) had continued to stay biochemically hyperthyroid at the end of one year. All were on anti-thyroid medications, and all eventually had surgeries.

Conclusions Empirical, fixed high dose (30 mCi) Iodine-131 therapy for solitary toxic thyroid nodules produces very good cure rates with very modest incidence of hypothyrodism, and should hence be considered as an effective option for management.