Long-term follow-up of nodular goiter - experience in fukushima area of north-east Japan

Takao Kunori; Hiroshi Yoshida

doi:10.1530/endoabs.110.EP1455

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Endocrine Abstracts (2025) 110 EP1455 | DOI: 10.1530/endoabs.110.EP1455

ECEESPE2025 ePoster Presentations Thyroid (198 abstracts)

Long-term follow-up of nodular goiter – experience in fukushima area of north-east Japan

Takao Kunori ¹ & Hiroshi Yoshida ¹

Author affiliations

¹Iwaki-city medical center, Department Surgery, Iwaki-city, Japan.

JOINT1557

Background: Benign thyroid nodules (NOD) has been generally considered to have no operative indication. However, long-term course is still unclear. In the present study, we reviewed 18 years’ NOD cases, including a year of nuclear power plant accidents (NPP, 2011), to find out its natural course.

Patients and Methods: 6,553 Japanese patients (2007-2024), who live in iodine rich lands of Fukushima, visited our thyroid clinic; mean age, 60 (female, 81%). Follow-up study was performed in 1,551 patients (4,883 times; 0- 18 years). Assays: Serology was performed for thyroid peroxidase antibody (TPO), anti-thyroglobulin antibody (TgAb), thyroid stimulating hormone receptor antibody (TRAb) 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). Cytology of NOD: Fine needle aspiration cytology (FNA); class 1 (normal), 7.3%; class 2 (benign), 42%; class 3 (malignancy not ruled out), 2.3%; class 4 (suspicious), 0.2%; class 5 (malignant), 3.0%; Solid 57%,　Cyst　43%. Changes of NOD: Enlargement rates of nodules (VR%, size%) were calculated from a formula; current VL(volume)/initial VL and size/initial size (of FNA nodules).

Results: 1) VR%: 24% down and(vs) 12% (46% no change: 1-year), 20% vs 15% (56%: 2-year). 16% vs 13% (49%: 3-year), 28% vs 11% (52%: 5-year) and 9.7% vs 5.3% (74%: 10 year). 2) Factors related with VR% (over 10 years): 3 factors had significant; thyroglobulin (Tg) as a UP factor, Tg/VL and age as DOWN factor. 3) Prediction of VR% after 5 years: a) Size at first visit: Increased size was 50% in 10-15 mm (initial size), whereas unchanged (60%) or decreased (27%) in 20-29mm. b) Tg: Tg/VL was associated with TgAb. 4) Influence of NPP accidents: There was no influence to statistics of NOD.

Discussion: A half of NOD remained unchanged/reduced. Up VL (200%-) generally observed in small NOD. Long term follow-up seemed not always necessary if FNA confirmed benign. Significance of autoantibodies was unclear. However, we do not know if these results are also applied to non-Japanese people.