Can increased tumoral vascularity be a quantitative predicting factor of lymph node metastasis in papillary thyroid microcarcinoma?

The aim of the present study was to evaluate the clinical implications of the vascular index (VI) as a predicting factor for central and lateral lymph node metastasis (LNM) in patients with papillary thyroid microcarcinoma (PTMC). From January 2011 to October 2011, 588 patients (495 females, 93 males) who were diagnosed with PTMC were included. Clinicopathologic characteristics of patients and ultrasound (US) features of the lesions including VI were evaluated retrospectively. The VI was measured with QLAB 7.0 quantification software using preoperative Doppler US images. Univariate and multivariate analysis were used to assess predictive factors of LNM. From 588 patients, 140 patients (23.8 %) had central LNM and 26 patients (4.4 %) had lateral LNM on pathologic results. The presence of lateral LNM [odds ratio (OR) 5.46; 95 % confidence interval (CI) = 2.19-13.64], bilaterality (OR 2.16; 95 % CI 1.17-4.01), and increased tumor size (OR 1.15; 95 % CI 1.04-1.28) were significant independent factors for predicting central LNM. The presence of central LNM (OR 5.58; 95 % CI 2.22-14.04), upper third location of malignancy (OR 2.50; 95 % CI 1.01-6.21), and tumor size (OR 1.34; 95 % CI 1.03-1.73) were significant independent factors for predicting lateral LNM. However, the VI was not a significant predicting factor for both central and lateral LNM. Therefore, the VI of PTMC may not be useful for predicting central and lateral LNM in patients with PTMC.