Diagnosis of thyroid malignancy using levels of trace element contents in nodular tissue
Background: Thyroid benign (TBN) and malignant (TMN) nodules are a common thyroid lesion. The differentiation of TMN often remains a clinical challenge and further improvements of TMN diagnostic accuracy are warranted. Objective: The aim of present study was to evaluate possibilities of using differences in trace elements (TEs) contents in nodular tissue for diagnosis of thyroid malignancy. Methods: Contents of thirty two TEs such as silver (Ag), aluminum (Al), boron (B),, beryllium (Be), bismuth (Bi), cadmium (Cd), cerium (Ce), cobalt (Co), chromium (Cr), cesium (Cs), iron (Fe), gallium (Ga), mercury (Hg), iodine (I), lanthanum (La), lithium (Li), manganese (Mn), molybdenum (Mo), neodymium (Nd), nickel (Ni), lead (Pb), praseodymium (Pr), rubidium (Rb), antimony (Sb), scandium (Sc), selenium (Se), samarium (Sm), tin (Sn), thallium (Tl), uranium (U), yttrium (Y), and zinc (Zn) were prospectively evaluated in “normal” thyroid (NT) of 105 individuals as well as in nodular tissue of thyroids with TBN (79 patients) and to TMN (41 patients). Measurements were performed using a combination of non-destructive instrumental neutron activation analysis with destructive method such as inductively coupled plasma mass spectrometry. Results: It was observed that in TMN tissue the mean mass fractions of I and Sc were lower while the mean mass fractions of Mo and Rb were higher than in both NT and TBN groups of samples. It was demonstrated that I content in nodular tissue is the most informative parameter for the diagnosis of thyroid malignancy. It was found that “Sensitivity”, “Specificity” and “Accuracy” of TMN identification using the I level in the needle biopsy of affected thyroid tissue was significantly higher than that using US examination and cytological test of fine needle aspiration biopsy. Conclusions: It was concluded that determination of the I level in a needle biopsy of TNs using non-destructive instrumental analytical method is a fast, reliable, and very informative diagnostic tool that can be successfully used as an additional test of thyroid malignancy identification.