Analysis of the Clinicopathologic Features of Papillary Thyroid Microcarcinoma Based on 7‐mm Tumor Size

• DOI: 10.1007/s00268-010-0886-5
• Publication Date: 2010-12-15T15:26:12Z
• Authors: Kwan Ju Lee; Yun Jung Cho; Say Jun Kim; Sang Chul Lee; Jeong Goo Kim; Chang Joon Ahn; Dong Ho Lee
• Keywords: Lymphovascular invasion

AbstractBackgroundWe examined the clinicopathologic features of papillary thyroid microcarcinomas (PTMCs) measuring ≤7 mm and compared them with those of PTMCs >7 mm.MethodsBetween January 2007 and June 2009, a total of 275 patients with PTMCs underwent surgery. They were divided into two groups. Group I included patients with tumors ≤7 mm, and group II included those with tumors >7 mm but ≤10 mm. We compared the two groups’ clinicopathologic features.ResultsTotal thyroidectomy was more often performed in group II (p = 0.003). Central lymph node metastases were identified in 30.6% of the patients in group I and in 47.8% of the patients in group II (p = 0.005). A statistically significant difference between the two groups was also found for capsule invasion (p < 0.0001), extrathyroidal extension (p = 0.005), and lymphovascular invasion (p = 0.025). On the multivariate analysis, central lymph node metastasis was the only independent factor associated with tumor size.ConclusionA PTMC ≤7 mm is less likely to have aggressive features, including central lymph node metastasis, capsule invasion, extrathyroidal extension, and lymphovascular invasion, than a PTMC >7 mm. Because the aggressiveness of PTMC was found mainly in the patients with tumors >7 mm, we think that a cutoff value of 7 mm may be considered the threshold of aggressiveness of PTMCs.