Head-to-head comparison of FNA cytology vs. calcitonin measurement in FNA washout fluids (FNA-CT) to diagnose medullary thyroid carcinoma. A systematic review and meta-analysis

Pierpaolo Trimboli,Jacopo Giannelli,Maurilio Deandrea,Bernardo Marques,Arnoldo Piccardo,Anna Crescenzi

doi:10.1007/s12020-021-02892-x

Abstract

PurposeThe sensitivity of cytology after fine needle aspiration (FNA-cytology) in detecting medullary thyroid carcinoma (MTC) is low. To overcome this problem, measuring calcitonin (CT) in washout fluid of FNA (FNA-CT) has been largely diffused and showed good performance. However, no evidence-based study exists comparing systematically the sensitivity of FNA-cytology and FNA-CT. This study aimed to systematically review the literature and collect data allowing a head-to-head comparison meta-analysis between FNA-cytology and FNA-CT in detecting MTC lesions.MethodsThe online databases of PubMed/MEDLINE and Scopus were searched until June 2021. Original articles reporting the use of both FNA-cytology and FNA-CT in the same series of histologically proven MTC lesions were included They were extracted general features of each study, number of MTC lesions (nodule and neck lymph nodes), and true positive and false negatives of both FNA-cytology and FNA-CT.ResultsSix studies were included. The sensitivity of FNA-cytology varied from 20% to 86% with a pooled value of 54% (95% CI 35–73%) and significant heterogeneity. The sensitivity of FNA-CT was higher than 95% in almost all studies with a pooled value of 98% (95% CI 96–100%) without heterogeneity. The sensitivity of FNA-CT was significantly higher than that of FNA-cytology.ConclusionsFNA-CT is significantly more sensitive than FNA-cytology in detecting MTC. Accordingly, FNA-CT represents the standard method to use in patients with suspicious MTC lesions, combined with cytology.

Highlights

Medullary thyroid carcinoma (MTC) is an infrequent thyroid malignancy originating from C-cells and occurring as a familial disorder in about one in five cases [1, 2]
The technical approach used in the six studies to prepare samples for FNA-cytology and FNA-CT is summarized in the Table 3
As reported in a meta-analysis published in 2015 [6], only 56% of histologically proven MTC lesions can be correctly detected by cytological evaluation

Summary

Introduction

Medullary thyroid carcinoma (MTC) is an infrequent thyroid malignancy originating from C-cells and occurring as a familial disorder in about one in five cases [1, 2]. Even if the cytological evaluation after fine needle aspiration (FNA-cytology) is recognized as the most reliable tool for the assessment of thyroid nodules, its sensitivity in detecting MTC is concerning [6, 7]. In this context, the Endocrine measurement of calcitonin (CT), the most sensitive circulating marker of MTC, can be interfered by several factors and its routine use in all patients with nodular thyroid disease has not been generally accepted [1, 2]. Several original papers have been published on this topic but no evidence-based study exists comparing systematically the sensitivity of FNA-cytology and FNA-CT

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