Utility of serum procalcitonin for screening and risk stratification of medullary thyroid cancer.
BACKGROUND
The clinical utility of procalcitonin has not been demonstrated across the whole spectrum of medullary thyroid cancer (MTC).


OBJECTIVE
This serum biomarker validation study aimed at defining the diagnostic accuracy of procalcitonin for screening and risk stratification of MTC and delineating biochemical thresholds predictive of lymph node involvement in the neck and mediastinum.


METHODS
This was a retrospective analysis at a tertiary referral center.


METHODS
Included in this study were 457 consecutive patients with previously untreated MTC, 112 of whom had procalcitonin and calcitonin serum levels determined before the initial operation.


METHODS
The intervention was compartment-oriented surgery.


METHODS
Main outcome measures included primary tumor diameter, extrathyroidal extension, lymph node metastases, distant metastases, and biochemical cure.


RESULTS
Receiver operating characteristics analyses revealed similar diagnostic accuracy for procalcitonin vs the current calcitonin standard, yielding comparable areas under the curve for primary tumors at thresholds of 10 (0.94 vs 0.93) and 40 (0.92 vs 0.84) mm; extrathyroidal extension (0.84 vs 0.83), lymph node metastasis (0.88 vs 0.86), and distant metastasis (0.93 vs 0.91). Lymph node metastases were present in the ipsilateral lateral neck with procalcitonin levels ≤1.0 ng/mL and the ipsilateral central neck with procalcitonin levels ≤0.25 ng/mL. Above a threshold of 1.0 ng/mL, lymph node metastases emerged in the contralateral central and lateral neck and above 5.0 ng/mL also in the upper mediastinum. When procalcitonin levels exceeded 1, 5, 10, and 50 ng/mL, biochemical cure rates declined to no more than 71%, 36%, 23%, and 10%, respectively.


CONCLUSIONS
Serum procalcitonin, having comparable diagnostic accuracy, has great potential to replace serum calcitonin as a new standard of care in the management of MTC because it does not need to be kept cool on ice or frozen and is easier to manage at the community level.
Department of General, Visceral, and Vascular Surgery, Martin Luther University Halle-Wittenberg, D-06097 Halle (Saale), Germany.
Andreas
A
Machens
Kerstin
K
Lorenz
Henning
H
Dralle
D000328:Adult; D014408:Biomarkers, Tumor / Q000097:blood; D002116:Calcitonin / Q000097:blood*; D015740:Calcitonin Gene-Related Peptide; D018278:Carcinoma, Neuroendocrine; D055088:Early Detection of Cancer / Q000379:methods*; D005260:Female; D006801:Humans; D008207:Lymphatic Metastasis; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D011498:Protein Precursors / Q000097:blood*; D012189:Retrospective Studies; D012307:Risk Factors; D012680:Sensitivity and Specificity; D013964:Thyroid Neoplasms / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology*
D014408:Biomarkers, Tumor; C000606589:CALCA protein, human; D011498:Protein Precursors; D002116:Calcitonin; D015740:Calcitonin Gene-Related Peptide