title: Analysis of the clinicopathologic features of papillary thyroid microcarcinoma based on 7-mm tumor size.
abstract: BACKGROUND
  We examined the clinicopathologic features of papillary thyroid microcarcinomas (PTMCs) measuring≤7 mm and compared them with those of PTMCs>7 mm.
  
  
  METHODS
  Between 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.
  
  
  RESULTS
  Total 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.
  
  
  CONCLUSIONS
  A 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.
authors.affiliation: Department of Surgery, College of Medicine, The Catholic University of Korea, Daejeon St. Mary's Hospital, 520-2, Daeheung-dong, Jung-gu, Daejeon, South Korea. leekj@catholic.ac.kr
authors.forename: Kwan Ju
authors.initials: KJ
authors.lastname: Lee
authors.forename: Yun Jung
authors.initials: YJ
authors.lastname: Cho
authors.forename: Say Jun
authors.initials: SJ
authors.lastname: Kim
authors.forename: Sang Chul
authors.initials: SC
authors.lastname: Lee
authors.forename: Jeong Goo
authors.initials: JG
authors.lastname: Kim
authors.forename: Chang Joon
authors.initials: CJ
authors.lastname: Ahn
authors.forename: Dong Ho
authors.initials: DH
authors.lastname: Lee
mesh_terms: D000328:Adult; D002277:Carcinoma; D002291:Carcinoma, Papillary; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000473:pathology