Endocrine Abstracts

The treatment of benign multinodular goitre (MNG) is controversial, but surgery is recommended for large compressive goitres in contrast to observation in small to medium sized MNG. While some patients decline surgery others have contraindications due to comorbidity. Therefore, non-surgical treatment alternatives are needed. Until recently, levothyroxine therapy was the preferred non-surgical alternative. But due to low efficacy and potential side-effects, international guidelines now disencourage its use. Conventional radioiodine (131-I)- therapy has been used for two decades as an effective and safe alternative to surgery in symptomatic MNG. Sine much higher activities of 131-I are employed when treating non-toxic than toxic MNG, there has been reluctance in many countries to use this modality. Frequently, the 131-I-uptake in a MNG is low, which makes the therapy less feasible. Other challenges are: unpredictable effect, diminishing effect with increasing goitre size, little data on long-term effects and side effects – especially risk of thyroid or extra-thyroidal malignancy. Short-term risk of radiation thyroiditis (2–3%), a 3–5% risk of developing Graves’ disease and a ca. 40% goitre size reduction is well accepted. With its ability to more than double the thyroid 131-I-uptake, recombinant human TSH (rhTSH) increases the retained radiation and thus enhances the goitre volume reduction by 35–56% at the expense of an up to 5-fold increased incidence of hypothyroidism. An alternative strategy is to reduce the administered 131-I-activity, with a factor corresponding to the rhTSH induced increase in 131-I-uptake. Hereby the extra-thyroidal irradiation can be reduced without compromising efficacy. Thus, although in its infancy, and still experimental (off-label use), rhTSH-augmented 131-I-therapy may profoundly alter the non-surgical treatment of benign non-toxic MNG. Short as well as long-term risk profile, efficacy, and cost need to be balanced against potential improved quality of life before routine use.

Partly supported by the Clinical Endocrinology Trust