Endocrine Abstracts

Background: Nodular goiter (NOD) is one of the most common disease, which does not always need surgery. Long-term outcomes and relation with thyroid hormones, however, are not clear. We analyzed in Japanese patients who take iodine enriched food.

Patients and methods: 3, 781 patients with NOD (solid type 37%, cystic 16%; 2007-2022); mean age, 57 (female, 80%) and 66 (man, 20%) entered in this study. Observation period was 5.1 years (mean; 1-21 years). Single solid nodules (n=1, 115; sNOD) were examined at year of 1, 2, 4, and 8 from the first visit. Serology was performed for thyroid peroxidase antibody (TPO), anti-thyroglobulin antibody (TgAb), thyroid stimulating hormone receptor antibody (TSH-RAb) and, in some patients, thyroid stimulating hormone antibody (TSAb). Hormonal assay was performed for free thyroxine (FT4), free triiodo-thyronine (F-T3), thyroid stimulating hormone (TSH) and thyroglobulin (Tg). Nodules were examined by ultrasonogram (US) and aspiration cytology. Enlargement rates (size%) of nodules were calculated by current size/ initial size (diameter in US). Statistical significance was determined by probability (P<0.05) in student-t or Kai-2 test.

Results: 1. Size%: sNOD with the rates (>110%) increased as observed years, 4%(year zero), 26% (1 year), 35% (2 year), 43%(4 year) and 56% (8 year and more). While sNOD with the rate (<90%) also increased 4% (year zero), 22% (1 year), 23% (2 year), 30% (4 year) and 17% (8 year and more). 26% of sNOD was unchanged after 8 years. 2. Initial size and size% at year 4-6: Size% was highest in small size (<1 mm, median 197%), then 150% (10=<<1 mm), 95% (20=<<1 mm) and 106% (1 mm=<)(P<0.05). 3. Changes of TSH: Patients with Low TSH (<0.05μIU/ml) increased as observed years; from 21% to 75%. TSH decreased from 1.30IU/ml (sd=1.67) to 0.79 IU/ml in 10 years (P<0.05). TSH decreased from 1.46 IU/ml (mean) to 0.74 IU/ml in 8 years (P<0.05). 4. Changes of FT4: Patients with FT4>1.1 ng/dl (normal 0.70-1.48), increased as observed years; from 17% to 49%. FT4 increased from 1.12 ng/dl (sd=0.27) to 1.24 IU/ml(sd=0.24) in 8 years (P<0.05). 5. Changes of Tg: Tg increased from 74 ng/dl (median) to 439 ng/dl in 8 years.

Conclusions: 2/3 of sNOD remained no growth. sNOD appeared to be associated with TSH and thyroid hormones.