Giovanella L, et al. - During this study, the role of procalcitonin (PCT) was gauged by experts in the screening of patients with thyroid nodules for medullary thyroid carcinoma (MTC) between January 2011 and December 2017. Yielded data demonstrated that the measurement of PCT was a sensitive and accurate method for the identification of MTC in patients with thyroid nodules. Therefore, it could prove to be a reliable alternative to calcitonin (CT) measurement.

Methods

• PCT was estimated in 2,705 patients with thyroid nodules referred to the centre between January 2011 and December 2017.
• During this study, those with a positive PCT were operated after positive confirmatory tests such as fine-needle aspiration, measurement of calcitonin (CT) in serum and fine-needle aspiration washouts or CT stimulation testing.
• Based on the results of further diagnostics, subjects with a negative PCT were operated.
• An analysis was performed of the diagnostic performance of PCT and the best cut-off level was selected via ROC curve analysis.

Results

• Out of 2,705 patients, 9 with positive serum PCT (ie above 0.1 μg/L) and 370 with negative PCT underwent thyroid surgery.
• Histological confirmation of MTC was achieved in all patients with positive PCT but not found in patients with negative PCT.
• Considerably higher serum PCT levels were discovered in patients with MTC (median 0.64 μg/L, range 0.16-12.9 μg/L) than in those without (median 0.075 μg/L, range 0.075-0.16 μg/L; P < .0001).
• In order to calculate the optimal PCT value, ROC curves were plotted, separating patients with MTC from those without.
• As per the data, the best cut-off was found to be 0.155 μg/L with sensitivity, specificity, positive and negative predictive values as well as accuracy of 100%, 99.7%, 91.7%, 100% and 99.7%, respectively.
• It was noted that the positive and negative likelihood ratios were 329 and zero, respectively.