Risk factors for skip metastasis in patients with papillary thyroid microcarcinoma

Background: Lymph node metastasis (LNM) is prevalent in papillary thyroid microcarcinoma (PTMC) and is essential when determining tumor stage and prognosis. Positive lateral LNM with negative central LNM is defined as skip metastasis. Thyroid carcinoma's risk factors for skip metastasis remain controversial, especially in PTMC. This study aimed to determine the clinical features as well as the risk factors of skip metastasis among patients with PTMC. Methods: We conducted retrospective research among patients with PTMC who were subjected to treatment at our Hospital between January 2018 and December 2019 by reviewing their medical records. A database containing demographic characteristics, ultrasonography features, blood test outcomes, operation information, pathology details, and follow-up information was constructed. The link between skip metastasis and clinicopathological features of PTMC was evaluated using univariate as well as multivariate analyses. Results: Overall, 293 patients diagnosed with PTMC and lateral LNM were included. There were 91 men (31.1%) and 202 women (68.9%). The median age was 38 (31-47) years. Fifty patients were diagnosed with skip metastases. Levels III and II + III were the most prevalent in single-level and two-level metastasis, correspondingly. Univariate and multivariate analyses detected two independent factors linked to skip metastasis in PTMC: female sex (odds ratio = 2.609, 95% confidence interval (CI): 1.135-6.000; p = 0.024) and location of the tumor (upper portion) (odds ratio = 2.959, 95% CI: 1.552-5.639; p = 0.001). Conclusions: Skip metastasis is prevalent in thyroid carcinoma. Female sex and tumor location (upper portion) are independently linked to skip metastasis in PTMC. Patients who have these two risk factors should undergo a meticulous preoperative and intraoperative evaluation of lymph node status.