The accuracy of ultrasonography in the preoperative diagnosis of cervical lymph node metastasis in patients with papillary thyroid carcinoma: A meta-analysis

Background Ultrasonography has been proposed to enhance preoperative assessment of cervical lymph node status in patients with papillary thyroid carcinoma (PTC). Management is most controversial for patients with a clinically negative (cN0) neck. We aimed to evaluate the diagnostic properties of ultrasonography in the detection of cervical lymph node metastasis in patients with PTC. Materials and methods Studies evaluating the diagnostic accuracy of Ultrasonography in the diagnosis of cervical lymph node metastasis in patients with PTC were systematically searched for in the MEDLINE, EMBASE, Cancerlit and Cochrane Library and other database from January 1995 to November 2010. Two reviewers independently abstracted data including research design, sample size, imaging technique and technical characteristics, method of image interpretation. By patient-based and region- or node-based data analyses, we determined pooled sensitivities and specificities across studies, and constructed summary receiver operating characteristic curves, and area under summary receiver operating characteristic curves were calculated. Results The pooled patient-based sensitivity for ultrasonography was 0.72 (95% CI, 0.46–0.88), specificity was 0.98 (95% CI, 0.84–1.00), and the area under the curve (AUC) was 0.94 (95% CI, 0.92–0.0.96). The pooled region- or node-based sensitivity for ultrasonography was 0.63 (95% CI, 0.47–0.76), specificity was 0.93 (95% CI, 0.73–0.99), and the AUC was 0.81 (95% CI, 0.77–0.84). For lesion-based analysis, the subgroup of lateral compartment lymph node involvement was found to have the highest sensitivity (0.72, 95% CI 0.68–0.75) and specificity (0.97, 95% CI 0.93–0.99) among the studies (p < 0.05). Study sensitivity was not correlated with the prevalence of cervical lymph node metastasis (patient-based: R2 = 0.0196, p = 0.7915; region- or node-based: R2 = 0.3835, p = 0.1381). Conclusions We conclude that preoperative ultrasonography is a good technique for the preoperative lymph node staging of PTC and is helpful for detecting metastatic cervical lymph nodes at the lateral group. High-quality prospective studies regarding ultrasonography in the evaluation of cervical lymph node status in patients with PTC are still needed to be conducted.