Endocrine Abstracts

Objectives: Acromegaly is a rare disease that can cause complications in multiple organs. Although excess IGF-1 may contribute to the development of thyroid nodules, the association between acromegaly and thyroid nodules is still a topic of debate, and the available data are limited and contradictory. The aim of this study was to investigate the potential influence of acromegaly and its treatment on thyroid nodules.

Methods: This is a retrospective, single-centre, real-world observational study on 43 patients with acromegaly (58% female, 42% male, mean age 50 ± 13 years) who underwent at least one thyroid ultrasound after the diagnosis. 30 patients had at least two years of ultrasound follow-up (median ultrasound follow-up 83 months, IQR 48-122). Information about biochemical data, and local or medical treatment for acromegaly were collected form electronic medical records. Good control of acromegaly was defined by normalization of serum IGF-1 values within the age-specific reference range. A change of at least 3 mm in the size of a thyroid nodule was considered significant.

Results: Thyroid nodules were found in 77% of patients of whom 64% had multinodular goiter (median size of the dominant nodule 10 mm, IQR 6-19). We found a positive correlation between IGF-1 levels at diagnosis and the maximum size of the dominant thyroid nodule (P = 0.035 Rho=0.64) in treatment-naïve patients. At the time of the last thyroid ultrasound, the majority of patients (28 out of 30) achieved good control of acromegaly, either through local treatments (8 patients) or medical treatment (20 patients). We observed a significant growth of the primary thyroid nodule in 9 patients (30%), a decrease in size in 8 (27%) and no significant changes in 13 patients (43%). No association was found between dimensional changes in the dominant thyroid nodule and the type of treatment for acromegaly. The thyroid nodules were classified according to their ultrasound characteristics: 40% were classified as EU-TIRADS-2, 44% as EU-TIRADS-3 and 16% as EU-TIRADS-4. Of these, 38% underwent fine needle aspiration but none were cytologically suspicious, and no patient was diagnosed with thyroid carcinoma.

Conclusions: We confirmed an increased prevalence of thyroid nodules in patients with acromegaly compared to the general population, in accordance with previous studies. The maximum size of the dominant thyroid nodule appears to correlate with the IGF-1 levels at diagnosis. Nevertheless, once achieving good control of acromegaly, the progression of thyroid nodules is comparable to that observed in the general population.