For early detection of medullary thyroid carcinoma should routine calcitonin screening be performed in patients with nodular thyroid disease?

OBJECTİVE : Calcitonin is a sensitive and valuable tumor marker synthesized by Parafollicular or C cells in the neuroendocrine structure of the thyroid gland and is also used in the diagnosis and follow-up of medullary thyroid carcinoma. The aim of our study; this study aims to evaluate its contribution to the early diagnosis of medullary thyroid carcinoma by evaluating the value of routine calcitonin in patients with nodular thyroid disease. METHODS:Our study included 2543 patients with nodular thyroid disease out of 3494 patients aged 18 and over, whose calcitonin levels were measured between 2010 and 2020 in the Department of Endocrinology, Faculty of Medicine, Dokuz Eylul University. Statistical data analysis of 93 patients with basal calcitonin value >10 pg/ml and nodular thyroid disease were performed. Patients with previously diagnosed MTC and familial MEN syndrome had been excluded from the study. The patients were evaluated retrospectively. RESULTS : Of the 2629 nodular thyroid patients, 1952(%77) were female and 592(%23) were male. Age range evaluated as 19-104. The mean age at diagnosis was 54.08 ± 14.40 in 93 nodular thyroid patients with baseline CT>10 pg/ml. Thirty-six (38.7%) of the patients were female and 57 (61.3%) were male. Possible causes of false positives; kidney failure in 24.7% of patients, autoimmune thyroid disease in 7.5%, pregnancy in 1.1%, bacterial infection in 11.8%, alcohol use in 1.1%, 8.6% β-blockers were used in, 5.4% had a different neuroendocrine tumor, and 21.5% had papillary ca. In 12 of 93 nodular thyroid patients with CT>10 pg/ml, MTC was diagnosed using different research methods before calcitonin in the nodule advanced examination. While the nodule was investigated further, the number of patients whose first calcitonin value was checked and it was found to be high was 5 (5.4%) patients who were operated on and the definitive pathology diagnosis was MTC. The prevalence of MTC obtained by routine calcitonin testing while investigating the thyroid nodule was evaluated as 0.2%. CONCLUSION : Various studies have been conducted on the importance and meaning of routine calcitonin monitoring in patients with thyroid nodules. According to the general results of other studies and our study, was proposed that it would be more meaningful to measure the CT value primarily from patients with suspected malignant clinical and ultrasound findings and/or malignant suspected malignancy as a result of FNA and with uncertain cytology, instead of routinely checking the CT values in all patients with nodular thyroid disease. In conclusion, the calcitonin test may be a sensitive and specific marker for detecting medullary thyroid carcinoma in thyroid nodules, however, routine evaluation of calcitonin due to both cost and reasons causing the limitation of the test (false positive and false negative causes of calcitonin) is still a matter of debate and more randomized multicenter studies are needed in terms of the significance of the test. KEY WORDS : Nodular Thyroid Disease, Medullary Thyroid Carcinoma, Calcitonin