Endocrine Abstracts

Background: Nodular goiter (NOD) is one of the most common disease (69% in our thyroid clinic). Although the nodular growth is generally slow, it may be influenced by thyroid hormones, autoimmunity or other factors. The analysis may contribute to predict the outcomes.

Patients and methods: 2,213 Japanese patients (2007–2018; Fukushima coast area) with NOD were enrolled in this study. Mean observation period was 6.4 years with 7 visits (1–50). They consist of female (80%, mean age 57) and man (20%, 66). 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 (F-T4), free triiodo-thyronine (F-T3), thyroid stimulating hormone (TSH) and thyroglobulin (Tg). Nodules were examined by ultrasonogram to estimate total volumes of nodules (VOL). Pathological diagnosis was made by a fine needle aspiration cytology. Growth rates of nodules (VR%) were calculated from a formula; (current VOL/initial VOL)/years.

Results: 1. VR: 33% of NOD remained unchanged after 2 years of follow-up period, whereas 29% reduced and 38% enlarged. 2. TSH: TSH decreased from 1.46 IU/ml (mean) to 0.79 IU/ml after 8 years (P<0.05). 3. TSH and NOD: VR (/year) yearly decreased from 7% (0–2 years) to 0.9% (16 years). Patients with high TSH(>3 IU/ml) showed high VR (26–68%). 4. Thyroid antibodies: Positive (+) rates were 28% in TPO and 22% in TgAb. Both were associated with reduction of VR: no increase of VR in TPO+, whereas an increase (up to 3–8%) in TPO- (P<0.05). TSH-R was associated with an increase of VR (from 2% to 11%). 5. Cytology: VR was highest in cancer (P<0.001). 6. Physical states: VR was high in youth (age 10–30) and decreased in aging (P<0.001). Female had higher VR (3.9) than man (0.13, P<0.05). 7. Drugs: Patients treated with Levothyroxine showed low VR (−2%), whereas those with Methimazole showed high VR (+20%).

Conclusions: Growth of NOD was associated with various factors including TSH, thyroid autoantibodies and age. The activity appeared to be lost according to the follow-up periods.