갑상선 미세유두상암에서 0.5 cm를 기준으로 한 크기에 따른 예후인자와의 관계와 수술 전 세침흡인세포검사 횟수 분석

Analysis of Relationship between Prognostic Factors and Number of Fine-Needle Aspiration Cytology (FNAC) Prior to Surgery for Papillary Thyroid Microcarcinoma According to Size

Purpose: Papillary thyroid microcarcinoma (PTMC) is defined as a papillary thyroid carcinoma ＜10 mm in greatest dimension without palpation. In general, prognosis of PTMC is very favorable. PTMC can present with advanced features like papillary thyroid carcinoma ＞10 mm. Indication of FNAC based only on tumor size is still in debate. Some favor the criteria of a size ＜5 mm without FNAC and some argue for more study of the indication of FNAC according to tumor size. We analyzed the relationship of prognostic factors and number of FNACs prior to surgery for PTMC according to 5 mm size criterion. Methods: Three hundred seven patients diagnosed with PTMC after surgery were enrolled. Based on tumor size, patients were divided into group 1 (≤5 mm, n=151) and group 2 (＞5 mm, n=156) and the prognostic factors and number of pre-surgical FNAC procedures were compared. Results: There were no significant differences in gender, age, site, accompanying benign disease, multifocality and bilaterality. Group 2 patients displayed more advanced features than group 1 patients concerning capsular invasion, lymph node metastasis and tumor stage. The number of FNAC procedures prior to the decision of surgery was not different in the two groups. Conclusion: PTMC exceeding 5 mm in size showed advanced features than smaller tumors. Further study about the use of FNAC according only to the size of thyroid nodules is warranted. (Korean J Endocrine Surg 2011;11: 152-157)