Procalcitonin as Marker of Recurrent Medullary Thyroid Carcinoma: A Systematic Review and Meta-Analysis

Abstract

Background: Calcitonin measurement is pivotal in the management of medullary thyroid carcinoma (MTC), but several pitfalls can affect its reliability. Other potential markers have been proposed, and procalcitonin (ProCT) has been reported as promising. The present study was undertaken to summarize the published data and provide more robust estimates on the reliability of ProCT as marker in the management of patients with MTC.

Methods: The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. The sources comprised studies published through May 2018. Journal Articles that reported series of MTC patients undergone ProCT during postoperative follow-up were searched. A random-effects model was used for statistical pooling of the data. The I² index was used to quantify the consistency among the studies. The Egger test evaluated the possible presence of significant publication bias. Quality assessment of the studies was performed according to Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2).

Results: According to inclusion and exclusion criteria five papers, reporting 296 MTC patients undergone ProCT evaluation, were finally selected. The number of MTC with recurrence was 140. The pooled sensitivity of ProCT in detecting recurrence was 96% (95% confidence interval [CI], 92% to 99%), with neither heterogeneity (I²=0%) nor publication bias (Egger test, 3.16; P=0.99). The pooled specificity was 96% (95% CI, 87% to 100%) with mild heterogeneity (I²=66.6%), while Egger test was not calculable.

Conclusion: The present meta-analysis provides evidence that ProCT is reliable to manage MTC patients during their postoperative follow-up.

Keywords: Calcitonin; Procalcitonin; Thyroid cancer, medullary; Thyroid nodule.

Fig. 1. Flow-chart of search and selection of papers. ProCT, procalcitonin; MTC, medullary thyroid carcinoma.

Fig. 2. Pooled sensitivity of procalcitonin in detecting REC MTC (random effect). REC, recurrent MTC; MTC, medullary thyroid carcinoma; CI, confidence interval.

Fig. 3. Pooled specificity of procalcitonin in identifying NED MTC (random effect). NED, no evidence of disease; MTC, medullary thyroid carcinoma; CI, confidence interval.