• Korean Journal of Head & Neck Oncology
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• v.25 no.1
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• pp.8-11
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• 2009

Background and Objectives : In the TNM 6th classification system, extrathyroidal invasion of differentiated thyroid carcinoma has been classified into T3(minimal invasion), T4a(extended invasion), and T4b(more extensive unresectable invasion) according to the degree and it has been recognized as an important prognostic factor. In this study, we investigated the prognostic significances of minimal extrathyroidal invasion in papillary thyroid carcinoma(PTC). Material and Methods : We retrospectively studied 221 patients who are underwent thyroidectomy due to PTC from September 2003 to December 2006. Fifty-four(24.4%) patients had a PTC with minimal extrathyroidal invasion(Group A) and 167(75.6%) patients had a PTC without extrathyroidal invasion(Group B). The existence of minimal extrathyroidal invasion was based on operative and pathological findings. Results : Minimal extrathyroidal invasion in PTC was related to tumor size, lymph node metastasis, and operative method(p<0.001). But, there is no significant difference in age, gender, and multifocality between Group A and B. Hashimoto's thyroiditis was observed more frequently in Group B(p=0.019). Conclusion : These findings suggest that minimal extrathyroidal invasion is related to poor prognostic factors in PTC. Therefore, aggressive surgical approach is required when there is evidence of minimal extrathyroidal invasion in preoperative radiologic examination or operative finding.