Research Article| Volume 165, ISSUE 3, P652-656, March 2019

The definition of lymph node micrometastases in pathologic N1a papillary thyroid carcinoma should be revised

Published:October 29, 2018DOI:



      The aim of this study was to identify the risk factors for structural recurrence with a focus on lymph node–related factors and to determine the optimal cutoff size of lymph node micrometastases in patients with pathologic N1a classical papillary thyroid carcinoma.


      We included patients who underwent total thyroidectomy with central compartment lymph node dissection for classic papillary thyroid carcinoma with pathologic N1a classification.


      A total of 398 patients were followed up for a median of 131 months. Structural recurrence occurred in 17.3% of patients (69/398). The multivariate analysis reported the following independent risk factors for structural recurrence: tumor size >1.95 cm, bilaterality, lymphatic and/or vascular invasion, a maximum diameter of the metastatic lymph node focus >3.5 mm, distribution of metastatic lymph node foci size >3.0 mm, and ≥4 metastatic lymph nodes.


      The newly proposed cutoff of 3.5 mm for a definition of lymph node micrometastasis in pathologic N1a papillary thyroid carcinoma patients can reclassify the risk estimates of structural recurrence, thus modifying postoperative management plans and follow-up strategies.
      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'


      Subscribe to Surgery
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect


        • Edge S.B.
        • Compton C.C.
        The American Joint Committee on Cancer: the 7th edition of the AJCC cancer staging manual and the future of TNM.
        Ann Surg Oncol. 2010; 17: 1471-1474
        • Haugen B.R.
        • Alexander E.K.
        • Bible K.C.
        • et al.
        2015 American Thyroid Association Management Guidelines for adult patients with thyroid nodules and differentiated thyroid cancer: the American Thyroid Association Guidelines Task Force on thyroid nodules and differentiated thyroid cancer.
        Thyroid. 2016; 26: 1-133
        • Cranshaw I.M.
        • Carnaille B.
        Micrometastases in thyroid cancer. An important finding.
        Surg Oncol. 2008; 17: 253-258
        • Ito Y.
        • Kudo T.
        • Kobayashi K.
        • Miya A.
        • Ichihara K.
        • Miyauchi A.
        Prognostic factors for recurrence of papillary thyroid carcinoma in the lymph nodes, lung, and bone: analysis of 5,768 patients with average 10-year follow-up.
        World J Surg. 2012; 36: 1274-1278
        • Kim S.J.
        • Park S.Y.
        • Lee Y.J.
        • et al.
        Risk factors for recurrence after therapeutic lateral neck dissection for primary papillary thyroid cancer.
        Ann Surg Oncol. 2014; 21: 1884-1890
        • Leboulleux S.
        • Rubino C.
        • Baudin E.
        • et al.
        Prognostic factors for persistent or recurrent disease of papillary thyroid carcinoma with neck lymph node metastases and/or tumor extension beyond the thyroid capsule at initial diagnosis.
        J Clin Endocrinol Metab. 2005; 90: 5723-5729
        • Lee C.W.
        • Roh J.L.
        • Gong G.
        • et al.
        Risk factors for recurrence of papillary thyroid carcinoma with clinically node-positive lateral neck.
        Ann Surg Oncol. 2015; 22: 117-124
        • Randolph G.W.
        • Duh Q.Y.
        • Heller K.S.
        • et al.
        The prognostic significance of nodal metastases from papillary thyroid carcinoma can be stratified based on the size and number of metastatic lymph nodes, as well as the presence of extranodal extension.
        Thyroid. 2012; 22: 1144-1152
        • Schneider D.F.
        • Chen H.
        • Sippel R.S.
        Impact of lymph node ratio on survival in papillary thyroid cancer.
        Ann Surg Oncol. 2013; 20: 1906-1911
        • Yip J.
        • Orlov S.
        • Orlov D.
        • et al.
        Predictive value of metastatic cervical lymph node ratio in papillary thyroid carcinoma recurrence.
        Head Neck. 2013; 35: 592-598
        • Sugitani I.
        • Kasai N.
        • Fujimoto Y.
        • Yanagisawa A.
        A novel classification system for patients with PTC: addition of the new variables of large (3 cm or greater) nodal metastases and reclassification during the follow-up period.
        Surgery. 2004; 135: 139-148
        • Lee Y.M.
        • Sung T.Y.
        • Kim W.B.
        • Chung K.W.
        • Yoon J.H.
        • Hong S.J.
        Risk factors for recurrence in patients with papillary thyroid carcinoma undergoing modified radical neck dissection.
        Br J Surg. 2016; 103: 1020-1025
      1. NCCN. National Comprehensive Cancer Network (NCCN) clinical practice guidelines in oncology, thyroid carcinoma; version 1. 2017. Available from: Accessed October 21, 2017.

        • Huvos A.G.
        • Hutter R.V.
        • Berg J.W.
        Significance of axillary macrometastases and micrometastases in mammary cancer.
        Ann Surg. 1971; 173: 44-46
        • Siegel R.J.
        Surgical pathology of lymph nodes in cancer staging: routine and specialized techniques.
        Surg Oncol Clin N Am. 1996; 5: 25-31
        • Sung T.Y.
        • Yoon J.H.
        • Song D.E.
        • et al.
        Prognostic value of the number of retrieved lymph nodes in pathological Nx or N0 classical papillary thyroid carcinoma.
        World J Surg. 2016; 40: 2043-2050
        • Chang Y.W.
        • Kim H.S.
        • Jung S.P.
        • et al.
        Pre-ablation stimulated thyroglobulin is a better predictor of recurrence in pathological N1a papillary thyroid carcinoma than the lymph node ratio.
        Int J Clin Oncol. 2016; 21: 862-868
        • Lee S.G.
        • Ho J.
        • Choi J.B.
        • et al.
        Optimal cut-off values of lymph node ratio predicting recurrence in papillary thyroid cancer.
        Medicine (Baltimore). 2016; 95: e2692
        • Wu M.H.
        • Shen W.T.
        • Gosnell J.
        • Duh Q.Y.
        Prognostic significance of extranodal extension of regional lymph node metastasis in papillary thyroid cancer.
        Head Neck. 2015; 37: 1336-1343
        • Lee J.H.
        • Lee E.S.
        • Kim Y.S.
        Clinicopathologic significance of BRAF V600E mutation in papillary carcinomas of the thyroid: a meta-analysis.
        Cancer. 2007; 110: 38-46