Endocrine Abstracts

Background: Calcitonin (CT) is a specific marker of Medullary Thyroid Carcinoma (MTC). However, its routine measurement in the assessment of nodular thyroid disease (NTD) remains controversial because MTC is rare and CT may have false positive results.

Objective: To evaluate the frequency of hypercalcitoninemia (hyperCT) among patients with benign NTD and to disclose possible underlying factors.

Methods: Retrospective study including patients investigated for NTD between 2018 and 2021. HyperCt was defined as CT > 14.5 pg/ml, according to our hospital cut-off. Patients either with familial history of/or with MTC, MEN2 or CT >100 pg/mL were excluded.

Results: Hypercalcitoninemia was documented in 75 cases out of 3209 CT requests (2,3%) corresponding to 75 individuals: 89.3% men, mean age 64.6±12.5 years (min 21 – max 88). Median CT value was 19.9 (min 15- max 78) pg/mL. Median CT was 17.3 and 20.5 pg/mL respectively in women and men (P = 0.28). In 62 individuals (82,7%), at least one factor likely to contribute for the CT increase was identified: Hashimoto’s thyroiditis - n=2, smoking - n=8, treatment with proton pump inhibitors (PPI) - n=19, treatment with beta-blockers (BB) - n=8, treatment with PPI + BB - n=4, treatment with corticosteroids (CCT) - n= 3. A comparative analysis of the CT level based on the presence or absence of each potential influencer was not statistically significant. Eighteen patients had chronic kidney disease (CKD), 7 under haemodialysis. In CKD patients, median CT was 23.6 (min 14.8 – max 72.5 pg/mL). In a linear regression analysis, the presence of CKD influenced the CT result (P = 0.008).

Conclusions: In this series, CKD and the use of PPI and/or BB are the more prevalent causes of non-malignant hypercalcitoninemia.