Is basal ultrasensitive measurement of calcitonin capable of substituting for the pentagastrin‐stimulation test?

Abstract

The ultrasensitive CT assay reduces the false-negative rate of basal CT measurements when diagnosing familial MTC and in postoperative follow-up compared with previously used assays. However, its sensitivity to detect C-cell disease remains lower than that of the Pg-stimulation test.

“Atypical” Non-Secretory Medullary Thyroid Carcinoma: Case Report and Review of the Literature

“…If we could divide these negative calcitonin MTC into two categories, one were cancer cells show diffuse staining for calcitonin and another with weak and focal immunoreactivity, we could say that in the first category MTC maintain its ability to produce calcitonin but lose its ability to secrete it, whereas in the second category cancer cells cannot produce calcitonin. In regards to the first type of negative calcitonin MTC, one could hypothesize that there might be a defect in the secretory mechanism, or that the tumor preferential secrete precursor peptides and aberrant forms of calcitonin instead of the mature molecule [6], or that a mutation in the calcitonin/CGRP gene is responsible for the normal or reduced serum calcitonin [4]. When it comes to the second category, we already know that in progressive disease calcitonin levels may decrease due to dedifferentiation [9,15], we could consider that tumor cells with weak calcitonin expression indicate a loss of function and there for dedifferentiation and more aggressive nature [7,14].…”

“…Although MTC is considered a well differentiated tumour, it is quite aggressive [3]. In fact it is the second most aggressive thyroid cancer after anaplastic carcinoma [4], with a mortality rate that ranges between 13, 4 -38% [2][3][4][5]. Its poor prognosis relies not only on its aggressive nature but also on its limited response to chemotherapy and radiation [6].…”

“…Parafollicular carcinoma cells retain their ability to express, synthetize and secrete calcitonin [4], making serum calcitonin an important tool not only for the diagnosis but also for the follow up and prognostication of patients with MTC [8,9]. The routine measurement of serum calcitonin has been an area of great dispute, mostly when it comes to cost-effectiveness because of the low prevalence of MTC and the unnecessary thyroidectomies resulting from false positive results [2,4].…”

“…The routine measurement of serum calcitonin has been an area of great dispute, mostly when it comes to cost-effectiveness because of the low prevalence of MTC and the unnecessary thyroidectomies resulting from false positive results [2,4]. There are a number of other causes besides MTC for hypercalcitonemia [2,4], making the false positive results of serum calcitonin a true diagnostic challenge. However false negative results are very rare [4].…”

“…There are a number of other causes besides MTC for hypercalcitonemia [2,4], making the false positive results of serum calcitonin a true diagnostic challenge. However false negative results are very rare [4]. In fact in the past 20 years there have been some reports of medullary thyroid cancer patients without elevated and in some cases even undetected serum calcitonin (Table 1).…”