Reduction in goiter size by 131I therapy in patients with non-toxic multinodular goiter.

A retrospective follow-up study of 131I treatment was performed in 10 females (median age 48 years, range 40-74 years) with non-toxic multinodular goiter. The median dose of 131I given was 20 mCi (range 14-65 mCi). Thyroid volume was measured by ultrasonography. The median follow-up period was 26 months (range 12-68 months). Nine patients had a reduction of goiter size: thyroid volume decreased from 88 +/- 14.9 ml (mean +/- SEM) to 49 +/- 10.9 ml 1 year after 131I treatment. The relative decrease of goiter size was 48% after 1 year (N = 9) and 59% after 2 years (N = 5). One patient did not respond and was referred for operation. Side effects were mild spontaneously resolving radiation thyroiditis in one patient and subclinical hypothroidism in four patients. In conclusion, 131I treatment of non-toxic goiter is an effective treatment at the expense of post-radiation (subclinical) hypothyroidism.