OncoTargets and Therapy (Aug 2016)

Tumor size interpretation for predicting cervical lymph node metastasis using a differentiated thyroid cancer risk model

  • Shi RL,
  • Qu N,
  • Yang SW,
  • Ma B,
  • Lu ZW,
  • Wen D,
  • Sun GH,
  • Wang Y,
  • Ji QH

Journal volume & issue
Vol. Volume 9
pp. 5015 – 5022

Abstract

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Rong-liang Shi,1–3,* Ning Qu,1,2,* Shu-wen Yang,1,2 Ben Ma,1,2 Zhong-wu Lu,1,2 Duo Wen,1,2 Guo-hua Sun,1,2 Yu Wang,1,2 Qing-hai Ji1,2 1Department of Head and Neck Surgery, Fudan University Shanghai Cancer Center, 2Department of Oncology, Shanghai Medical College, Fudan University, 3Department of General Surgery, Minhang Hospital, Fudan University, Shanghai, People’s Republic of China *These authors contributed equally to this work Abstract: Lymph node metastasis (LNM) is common in differentiated thyroid cancer (DTC), but management of clinically negative DTC is controversial. This study evaluated primary tumor size as a predictor of LNM. Multivariate logistic regression analysis was used for DTC patients who were treated with surgery between 2002 and 2012 in the Surveillance, Epidemiology, and End Results (SEER) database, to determine the association of tumor size at 10 mm increments with LNM. A predictive model was then developed to estimate the risk of LNM in DTC, using tumor size and other clinicopathological characteristics identified from the multivariate analysis. We identified 80,565 eligible patients with DTC in the SEER database. Final histology confirmed 9,896 (12.3%) cases affected with N1a disease and 8,194 (10.2%) cases with N1b disease. After the patients were classified into subgroups by tumor size, we found that the percentages of male sex, white race, follicular histology, gross extrathyroidal extension, lateral lymph node metastasis, and distant metastasis gradually increased with size. In multivariate analysis, tumor size was a significant independent prognostic factor for LNM; in particular, the odds ratio for lateral lymph node metastasis continued to increase by size relative to a 1–10 mm baseline. The coefficient for tumor size in the LNM predictive model was ~0.20, indicating extra change in log(odds ratio) for LNM as 0.2 per unit increment in size relative to baseline. In conclusion, larger tumors are likely to have aggressive features and metastasize to a cervical compartment. Multistratification by size could provide more precise estimates of the likelihood of LNM before surgery. Keywords: differentiated thyroid cancer, size, lymph node metastasis, risk, SEER

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