Ricerc@Sapienza

Aim: Due to the limits of calcitonin, other markers are warranted to better manage medullary thyroid carcinoma
patients, and procalcitonin has been reported as promising. Here we aimed to evaluate procalcitonin as a marker
of medullary thyroid carcinoma in the post-treatment follow-up.
Methods: Medullary thyroid carcinoma patients previously treated by thyroidectomy were enrolled. After complete
imaging work-up (i.e. ultrasonography, computed tomography, magnetic resonance and 18FDG-PET-CT) we
identified patients with structural recurrent/persistent medullary thyroid carcinoma (active medullary thyroid
carcinoma) and subjects with no evidence of disease. Then, both calcitonin and procalcitonin were measured and
their performance analyzed.
Results: The final series included 55 medullary thyroid carcinoma patients treated and followed-up for about five years.
Of these, 43 were assessed as no evidence of disease, and 12 as active medullary thyroid carcinoma. The median value
of procalcitonin was significantly higher (P in those with no evidence of disease (0.10 ng/mL). Also, calcitonin levels of active medullary thyroid carcinoma (96.7
pg/mL) were significantly (P characteristic curve analysis, the optimal cut-off of procalcitonin was ?0.32 ng/mL with 92% sensitivity and 98%
specificity, while the most accurate threshold of calcitonin was ?12.0 pg/mL with 100% sensitivity and 91% specificity.
There was no active medullary thyroid carcinoma with simultaneously negative results of procalcitonin and calcitonin.
Conclusions: Procalcitonin is reliable in discriminating medullary thyroid carcinoma patients with active disease
from those with no evidence of disease. We suggest using procalcitonin as complementary to calcitonin to follow-up
medullary thyroid carcinoma patients.