Procalcitonin: a promising role in medullary thyroid carcinoma?
Teresa Azevedo, Mariana Martinho, Teresa Martins, Nuno Cunha, Frederico Valido & Fernando Rodrigues
Introduction: Procalcitonin (PCT) is currently used as a sepsis marker. Studies have shown that this prohormone is elevated in patients with medullary thyroid carcinoma (MTC) and, additionally, that its assay could have less limitation than calcitonin (CT).
Objective: To evaluate the concordance between the values of CT and PCT.
Methods: CT, PCT and carcinoembryonic antigen (CEA) were measured in a total of 57 subjects. CEA and CT were measured by an immunochemiluminometric assay using an Immulite 2000 analyzer (Siemens Healthcare) and PCT was measured on a Kryptor system (BRAHMS) TRACE technology (Time Resolved Amplified Cryptate Emission). We used the Pearson correlation test.
Results: We included 41 patients with MTC and 16 controls (9 with follicular cell-derived carcinoma and 7 with benign thyroid disease). Sixty six percent of the patients were female. In the control group all patients had normal CT, PCT and CEA levels. Of the 41 patients with MTC, high CT was detected in 15 (range: 2431 745 pg/ml), high procalcitonin in 12 (range: 0.9134 ng/ml) and elevated CEA in 12 (range: 7.52536 ng/ml). All 3 patients with borderline high CT (range: 24.136.6 pg/ml) had normal PCT levels (<0.5 ng/ml) and no evidence of residual disease. A significant positive correlation between levels of CT and PCT (r2=0.9, P<0.001) was found.
Conclusion: A strong correlation was observed between CT and PCT levels in patients with MTC. The PCT assay together with CT could represent, in future, a promising complementary MTC tumor marker. Long-term prospective studies will be fundamental to determine the value of each one on detection of residual disease.