Oncology · Medical Literature
[Fine-needle aspiration cytology and fine-needle aspirate calci-tonin measurement for diagnosing medullary thyroid carci-noma: a meta-analysis].
Abstract
To systematically evaluate the diagnostic value of fine-needle aspiration cytology (FNAC) and fine-needle aspirate calcitonin (FNA-CT) measurement in medullary thyroid carcinoma (MTC). This study has been registered in the International Prospective Register of Systematic Reviews (PROSPERO, CRD420251243288) and was conducted and reported in accordance with the Preferred Reporting Items for a Systematic Review and Meta-analysis of Diagnostic Test Accuracy Studies (PRISMA-DTA) 2018. Relevant studies evaluating FNAC and FNA-CT for the diagnosis of MTC were systematically searched in Chinese and English databases from January 1, 1995 to December 31, 2024. The methodological quality of the included studies was assessed using the QUADAS-2, and meta-analysis was performed using Stata 16.0. The threshold effect was evaluated using the Spearman correlation test, and heterogeneity was assessed using Cochran's Q test and the I² statistic. A fixed-effects or random-effects model was selected according to the degree of heterogeneity. The pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were calculated, and summary receiver operating characteristic (SROC) curves and forest plots were generated to evaluate diagnostic performance. Meta-regression analysis was further conducted to explore potential sources of heterogeneity. Deeks' funnel plot was used to assess publication bias, while Fagan nomogram and the likelihood ratio scattergram were used to evaluate clinical utility. A total of 13 studies involving 937 patients with 444 MTC lesions were finally included. The Spearman correlation test showed no obvious threshold effect for FNAC in diagnosing MTC, whereas a potential threshold effect was observed for FNA-CT. Heterogeneity analysis revealed varying degrees of heterogeneity across the diagnostic performance indicators of both FNAC and FNA-CT; therefore, random-effects models were used for pooled analysis. For FNAC, the pooled sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic odds ratio were 0.56 (95%CI: 0.51-0.61), 0.98 (95%CI: 0.94-1.00), 34.25 (95%CI: 8.98-130.62), 0.45 (95%CI: 0.39-0.51), and 76.97 (95%CI: 18.72-316.52), respectively. For FNA-CT, the corresponding values were 0.98 (95%CI: 0.94-0.99), 0.97 (95%CI: 0.94-0.99), 37.42 (95%CI: 16.91-82.80), 0.02 (95%CI: 0.01-0.06), and 1891.55 (95%CI: 351.09-10 191.13), respectively. The SROC AUCs of FNAC and FNA-CT for diagnosing MTC were 0.65 and 1.00, respectively. Meta-regression analysis suggested that the heterogeneity of FNAC might be related to study design and detection method, whereas no significant source of heterogeneity was identified for FNA-CT. Possible publication bias was detected for both methods. Both Fagan nomogram analysis and likelihood ratio scattergram analysis showed that FNA-CT had high clinical value for both confirming and excluding MTC, whereas FNAC had good value for confirming MTC but limited value for excluding it. FNA-CT demonstrates high diagnostic value for MTC, with overall diagnostic efficacy superior to that of FNAC.
Clinical relevance
In patients with thyroid nodules suspected for medullary thyroid carcinoma (MTC), what are the pooled diagnostic performance characteristics (sensitivity, specificity, likelihood ratios, and diagnostic odds ratio) of fine-needle aspiration cytology (FNAC) alone and fine-needle aspirate calcitonin measurement (FNA-CT) alone, as determined by a systematic review and meta-analysis of studies published between 1995 and 2024? __SNAPSHOT__ {"studyDesign":"Systematic review and meta-analysis of diagnostic test accuracy studies (PRISMA-DTA 2018 compliant; PROSPERO registered: CRD420251243288)","setting":"International; systematic search of Chinese and English databases; no single clinical institution","sampleSize":"not reported (number of included studies and total patients not provided in the available abstract excerpt)","population":"Patients with thyroid nodules evaluated for medullary thyroid carcinoma using FNAC and/or FNA-CT; specific inclusion/exclusion criteria not fully detailed in the available abstract","intervention":"Fine-needle aspiration cytology (FNAC) and fine-needle aspirate calcitonin measurement (FNA-CT) for diagnosis of MTC","comparator":"Implicit head-to-head comparison between FNAC and FNA-CT; reference standard assumed to be histopathological confirmation (not explicitly stated in the available abstract excerpt)","primaryOutcome":"Pooled diagnostic performance metrics: sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and summary receiver operating characteristic (SROC) area under the curve (AUC) for FNAC and FNA-CT in diagnosing MTC","followUp":"not applicable (cross-sectional diagnostic accuracy design)","fundingSource":"not reported"}
Key findings
The abstract excerpt provided is truncated and does not include the numerical results of the meta-analysis. Specifically, pooled sensitivity, specificity, positive and negative likelihood ratios, diagnostic odds ratios, SROC AUC values, confidence intervals, p-values, and heterogeneity statistics (I² from Cochran's Q test) are not available from the supplied text. Subgroup analyses, threshold effect evaluation (Spearman correlation), and publication bias assessments are described as planned methodological components but their results are not reported in the available abstract. No NNT or NNH is calculable. No adverse event data are applicable to a diagnostic accuracy study of this type. All quantitative findings are therefore designated: not reported.
Practice implications
IMPORTANT LIMITATION: Only a truncated abstract was provided; the results, conclusions, and discussion sections of this meta-analysis are unavailable. Accordingly, no quantitative conclusions about the diagnostic accuracy of FNAC or FNA-CT for MTC can be drawn from this specific paper. What can be established from the methodology is that the authors conducted a rigorous, PROSPERO-registered, PRISMA-DTA 2018-compliant meta-analysis searching both Chinese and English databases over a 30-year window (1995–2024), employed QUADAS-2 for quality appraisal, applied fixed- or random-effects modeling based on heterogeneity, and planned SROC analysis — all considered appropriate methods for diagnostic accuracy meta-analyses. The clinical relevance of the research question is well established in the existing literature: FNAC alone is known to have suboptimal sensitivity for MTC (approximately 50–65%), while FNA-CT measurement has demonstrated higher sensitivity (89–100%) and specificity in prior independent meta-analyses. Whether this new analysis, incorporating recent studies and Chinese-language literature, alters existing estimates or provides new subgroup insights cannot be determined without the full results. The findings are expected to be most applicable to patients with thyroid nodules and elevated or borderline serum calcitonin levels; patients with purely incidental nodules and no calcitonin elevation may not be adequately represented. Practice implications cannot be assessed without the complete data. __LIMITATIONS__ 1. Only a truncated abstract is available; results, conclusions, and full methodological details cannot be evaluated. 2. The number of included studies and total patient population are not reported in the excerpt, preventing assessment of statistical power or precision of pooled estimates. 3. Heterogeneity in calcitonin assay platforms, cutoff values, and cytologic classification systems across included studies is expected to be substantial and may limit the validity of pooled estimates. 4. The reference standard (histopathology) is assumed but not confirmed in the available text, raising potential verification bias concerns. 5. Threshold effect (evaluated by Spearman correlation) is a recognized source of heterogeneity in diagnostic accuracy meta-analyses that could inflate or deflate SROC AUC. 6. Inclusion of Chinese-language studies, while a methodological strength for comprehensiveness, may introduce reporting quality heterogeneity. 7. Funding source is not reported, precluding assessment of potential sponsorship bias. 8. Applicability to sporadic versus hereditary MTC, microcarcinoma versus macroinvasive disease, and lymph node versus primary nodule assessment cannot be evaluated from the available abstract. __BOTTOM_LINE_CATEGORY__ low_certainty __BOTTOM_LINE__ This PROSPERO-registered, PRISMA-DTA 2026 meta-analysis systematically evaluates the diagnostic accuracy of FNAC and FNA-CT for medullary thyroid carcinoma across 30 years of Chinese and English literature, using rigorous QUADAS-2 quality appraisal and SROC analysis. The abstract provided is truncated and no quantitative results are available; therefore, no evidence-based practice recommendation can be derived from this specific publication at this time. Clinicians should await full publication to determine whether the pooled estimates confirm, refine, or challenge current guideline recommendations favoring FNA-CT supplementation when FNAC is inconclusive or suspicious for MTC.