Calcitonin reserve in different stages of atrophic autoimmune thyroiditis

Calcitonin levels in autoimmune atrophic gastritis-related hypergastrinemia

PURPOSE

Calcitonin (Ct) is currently the most sensitive biochemical marker of C-cell disease (medullary thyroid cancer [MTC] and C-cell hyperplasia), but its specificity is relatively low. Our aim was to examine whether autoimmune atrophic gastritis (AAG) and chronic hypergastrinemia, with or without chronic autoimmune thyroiditis (AT), are conditions associated with increased Ct levels.

METHODS

Three groups of patients were consecutively enrolled in this  multicentric study: group A consisted of patients with histologically-proven AAG (n = 13; 2 males, 11 females); group B fulfilled the criteria for group A but also had AT (n = 92; 15 males, 77 females); and group C included patients with AT and without AAG (n = 37; 6 males, 31 females).

RESULTS

Median Ct levels did not differ between the three groups. Ct levels were undetectable in: 8/13 cases (61.5%) in group A, 70/92 (76.1%) in group B, and 27/37 (73.0%) in group C. They were detectable but ≤ 10 ng/L in 4/13 (30.8%), 20/92 (21.7%) and 7/37 (18.9%) cases, respectively; and they were > 10 ng/L in 1/13 (7.7%), 2/92 (2.2%) and 3/37 (8.1%) cases, respectively (P = 0.5). Only three patients had high Ct levels (> 10 ng/L) and high gastrin levels and had an MTC. There was no correlation between Ct and gastrin levels (P = 0.353, r = 0.0785).

CONCLUSIONS

High gastrin levels in patients with AAG do not explain any hypercalcitoninemia, regardless of whether patients have AT or not. This makes it mandatory to complete the diagnostic process to rule out MTC in patients with high Ct levels and AAG.

Presence or severity of Hashimoto's thyroiditis does not influence basal calcitonin levels: observations from CROHT biobank

PURPOSE

The influence of Hashimoto's thyroiditis (HT) on calcitonin (Ct) production is unresolved question. The aim of this study was to explore if basal Ct levels are influenced by the presence/severity of HT or correlated with clinical phenotypes of HT patients.

METHODS

We included 467 HT patients and 184 control participants, from Croatian Biobank of HT patients (CROHT), in this retrospective study. Calcitonin levels between HT patients and controls were compared using Mann-Whitney test. Ct levels between two subgroups of HT patients, divided by intake of levothyroxine (LT4) therapy, were additionally tested to take into account the illness severity. Spearman rank correlation test was used to analyze correlations between Ct levels and 14 relevant phenotypes.

RESULTS

We have not detected significant differences in median Ct levels between HT patients and controls (2.2 vs 2.35 pg/mL, respectively, P = 0.717) nor in-between two subgroups of HT patients (P = 0.347). We have not detected statistically significant correlations between Ct levels and clinical phenotypes, although we identified three weak nominal correlations: negative correlation of Ct with TgAb in all HT patients (r = - 0.1, P = 0.04); negative correlation of Ct with age in subgroup of HT patients without LT4 therapy (r = - 0.13, P = 0.04); positive correlation of Ct with BSA in subgroup of HT patients on LT4 therapy (r = 0.16, P = 0.042).

CONCLUSION

Our results suggest that HT patients of all disease stages preserve Ct production as healthy individuals and there is no need for Ct measurements in the absence of a nodule. Additional confirmation and clarification of observed nominal correlations are needed due to potential clinical relevance of TgAb and age-dependent Ct decrease in HT women.

Calcitonin levels by ECLIA correlate well with RIA values in higher range but are affected by sex, TgAb, and renal function in lower range

Calcitonin (CT) is a marker for both initial diagnosis and monitoring of patients with residual or recurrent medullary thyroid carcinoma (MTC). In Japan, serum CT had been measured by radioimmunoassay (RIA) until recently. Electrochemiluminescence immunoassay (ECLIA) became commercially available in 2014, and this technique is now the only method used to examine CT concentration. The purposes of this study were to investigate the correlations between the CT concentration measured with ECLIA (ECLIA-CT) and RIA (RIA-CT) and to explore the clinical characteristics of patients with elevated ECLIA-CT. CT concentrations of 348 sera samples from 334 patients with various thyroid disorders including nine MTC were measured using both assays. The correlation analysis revealed an excellent correlation between ECLIA-CT and RIA-CT among the cases with CT level >150 pg/mL by both assays (r_s = 0.991, p < 0.001). However, 63% of all samples exhibited undetectable ECLIA-CT, while their RIA-CTs were measured between 15 and 152 pg/mL. The ECLIA-CTs in all patients who underwent total thyroidectomy for non-MTC showed low concentrations. High ECLIA-CT was observed in patients with MTC or pancreas neuroendocrine tumor. ECLIA-CT was also increased in 14 other male patients with non-MTC, including four with renal failure. Multivariate logistic regression analysis showed that male sex, negative TgAb, and lower estimated glomerular filtration rate were independent factors to predict detectable ECLIA-CT (≥0.500 pg/mL). These results indicate that ECLIA-CT correlates well with RIA-CT in higher range and is affected by sex, TgAb, and renal function.

Influence of chronic autoimmune thyroiditis and papillary thyroid cancer on serum calcitonin levels

BACKGROUND

Serum calcitonin (sCt) is measured in many patients with nodular thyroid disease, and the possibility of a false-positive result is a matter of concern, particularly in the case of mild hypercalcitoninemia. Among the conditions reported to cause sCt elevation, Hashimoto's thyroiditis (HT) and papillary thyroid carcinoma (PTC) are relevant. In view of the high frequency of these conditions in patients with nodular disease and the controversy regarding the extent to which they contribute to hypercalcitoninemia, the objective of this study was to determine the influence of the presence of HT and PTC on sCt levels.

METHODS

Three groups of patients >12 years of age were studied. The first group (group A, n=492) consisted of patients with nodular disease evaluated before thyroidectomy and without medullary thyroid carcinoma (MTC) upon histology. The second group (group B, n=583) consisted of subjects without nodules on ultrasound. The third group (group C, n=62) consisted of patients with PTC and distant metastases after total thyroidectomy. The levels of sCt and frequency of elevated sCt were compared in patients with versus without HT (groups A and B) and those with PTC>1 cm versus without PTC (group A).

RESULTS

No difference in sCt levels or in the frequency of elevated sCt was observed between patients with and without HT, irrespective of sex. Moreover, the presence of PTC>1 cm did not influence sCt levels or the frequency of hypercalcitoninemia. In fact, none of the 1075 patients in groups A and B had sCt>40 pg/mL, regardless of the presence of HT and PTC. Serum calcitonin was undetectable in any patient of group C.

CONCLUSIONS

The finding of hypercalcitoninemia in patients with nodular disease should be interpreted as a suspicion of MTC, even in the presence of associated HT or cytology suggestive of PTC.

Interpretation of serum calcitonin in patients with chronic autoimmune thyroiditis

Calcitonin (CT) is an important clinical marker for the diagnosis and follow-up of medullary thyroid carcinoma, although it is not absolutely specific. Some authors have reported C-cell hyperplasia in a number of thyroid specimens affected by Hashimoto's thyroiditis. The association between thyroiditis and hypercalcitoninemia is still controversial because some authors have reported low CT levels. The aim of this study is to evaluate the basal CT values in patients with and without thyroid autoimmunity. From May 2005 to February 2010, 1073 patients underwent ultrasonography-guided fine-needle aspiration cytology at the Thyroid Center of Sapienza University of Rome, with evaluation of basal serum FT4, FT3, TSH, and antithyroid peroxidase (anti-TPO) antibodies as well as CT levels. Forty-one patients presented a basal CT level above the reference upper limit. The mean serum CT was significantly lower in women than in men (4.28 ± 6.63 vs 7.50 ± 25.50  pg/ml; P<0.01). Basal serum CT was not significantly higher in patients showing anti-TPO Ab positivity (4.71 ± 6.46 vs 4.84 ± 13.11  pg/ml; P>0.05). Importantly, the rate of 'suspicious' CT values (above the 10  pg/ml cutoff) was not significantly different between patients with or without thyroid autoimmunity (3.9 vs 3.0%). Patients with hypercalcitoninemia suffering from chronic autoimmune thyroiditis should undergo the same clinical evaluation procedure as patients do without thyroid autoimmunity.

Hypercalcitoninemia is not pathognomonic of medullary thyroid carcinoma

Hypercalcitoninemia has frequently been reported as a marker for medullary thyroid carcinoma. Currently, calcitonin measurements are mostly useful in the evaluation of tumor size and progression, and as an index of biochemical improvement of medullary thyroid carcinomas. Although measurement of calcitonin is a highly sensitive method for the detection of medullary thyroid carcinoma, it presents a low specificity for this tumor. Several physiologic and pathologic conditions other than medullary thyroid carcinoma have been associated with increased levels of calcitonin. Several cases of thyroid nodules associated with increased values of calcitonin are not medullary thyroid carcinomas, but rather are related to other conditions, such as hypercalcemias, hypergastrinemias, neuroendocrine tumors, renal insufficiency, papillary and follicular thyroid carcinomas, and goiter. Furthermore, prolonged treatment with omeprazole (>2-4 months), beta-blockers, glucocorticoids and potential secretagogues, have been associated with hypercalcitoninemia. An association between calcitonin levels and chronic auto-immune thyroiditis remains controversial. Patients with calcitonin levels >100 pg/mL have a high risk for medullary thyroid carcinoma (approximately 90%-100%), whereas patients with values from 10 to 100 pg/mL (normal values: <8.5 pg/mL for men, <5.0 pg/mL for women; immunochemiluminometric assay) have a <25% risk for medullary thyroid carcinoma.In multiple endocrine neoplasia type 2 (MEN2), RET mutation analysis is the gold-standard for the recommendation of total preventive thyroidectomy to relatives at risk of harboring a germline RET mutation (50%). False-positive calcitonin results within MEN2 families have led to incorrect indications of preventive total thyroidectomy to RET mutation negative relatives. In this review, we focus on the differential diagnosis of hypercalcitoninemia, underlining its importance for the avoidance of misdiagnosis of medullary thyroid carcinoma and consequent incorrect recommendation for thyroid surgery.

Calcium homeostasis in thyroid disease in dogs and cats

Hyperthyroidism is the most common endocrine disorder of cats, and hypothyroidism is the most common endocrine disorder of dogs. Little is known regarding the effects of hyperthyroidism, hypothyroidism, or treatment of these disorders on calcium metabolism in the dog or cat, however, especially any potential effects on bone. With better diagnostic tools, better treatments, and increased longevity of pets, the clinical impact of thyroid disorders on calcium metabolism and bone may be uncovered.