Should serum calcitonin be routinely measured in patients presenting with thyroid nodule?

BACKGROUND: The European Thyroid Association recommends serum calcitonin measurement in thyroid nodule cases. In contrast, the American Thyroid Association is ambivalent. In this institution, thyroid nodules cases are subject to a multidisciplinary evaluation of the clinical history and examination, ultrasound and scintigraphy, CT scan and sometimes MRI scan, biochemistry and histopathology of biopsies. We report on the current use of plasma calcitonin measurements in the context of changing practice which has not included screening of all thyroid nodules.

METHODS: Laboratory records were searched from the beginning of January 2010 to the end of April 2016 for all serum calcitonin measurements.

RESULTS: There were 44 patients (30 females, age range 31 to 87 years with median 57.5) and 14 males, age range 20 to 85 years with median 53.4 years) who had a serum calcitonin measured. Of these 33 patients did not have a detectable serum calcitonin. There were 3 patients who had an initial elevated serum calcitonin which became undetectable over time. Over the same time period, a total of 2070 patients presented with thyroid nodules. Medullary thyroid cancer (MTC) was found in 7 cases. Thus assuming all MTC cases had calcitonin measured, MTC is 7 of 341 (2.05%) of the total thyroid cancer burden at the hospital and 7 of 2070 (0.338%) of all thyroid nodules. Our practice is not to routine screen all nodules for MTC.

CONCLUSIONS: Because patients with a nodule are subjected to ultrasound scanning and biopsy, when the nodule size is greater than 5 cm or when there is a modifying ultrasound or clinical characteristic, the consensus at the multidisciplinary conference on thyroids rather than universal calcitonin screening of all nodules is the better option in our judgement.