Papillary Thyroid Microcarcinoma : A Report of Impact of Initial Therapy in 2035 Patients

1. Papillary Thyroid Microcarcinoma: A Report of Impact of Initial Therapy in 2035 Patients Jeonghun Lee, Su Han Seo, Euy Young Soh Department of Surgery, Ajou University

2. Introduction Introduction Papillary thyroid carcinoma ① accounts for up to 80% of thyroid cancer ② papillary microcarcinoma : 36~60% of papillary thyroid cancer Discrepancy of treatment strategies ① geographical discrepancy : Western vs. Japan a. total thyroidectomy vs. lobectomy b. therapeutic vs. prophylactic CCND c. radioiodine therapy ② temporal discrepancy : at Mayo Clinic (Hay et al) a. 1940~54 - most lobectomy and no RAI b. 1985~ - most total thyroidectomy and 50% RAI therapy

3. Introduction Prognostic factors for recurrence - different among the institutions • Buffet et al ( Europ J endo 2012 ) : LN metastasis, multifocality, male, total size of multifocal tumor>20mm) • Kim TY et al ( BMC cancer 2008 ) : male, lateral cervical LN metastasis • Chow et al ( Cancer 2003 ) : multifocality, limited surgery • Hay et al ( Surgery 1992 ) : LN metastasis, limited surgery

4. Purpose : To investigate the prognostic factors for recurrence in PTMC patients.

5. Materials and Methods Periods : Jan.1994 ~ Oct. 2010 Patients : 2035 PTMC patients who underwent thyroidectomy at Ajou University Hospital Inclusion criteria ① papillary thyroid microcarcinoma ② underwent primary surgical therapy at Ajou University Hospital

6. Materials and Methods • Strategy for papillary thyroid cancer at Ajou University Hospital ① Lobectomy : papillary thyroid caner < 1cm, no familial history, no capsular invasion, no multifocality and no LN metastasis. ② Central compartment LN dissection(CCND) : if malignancy on FNA cytology or frozen section biopsy  prophylactic CCND was performed ③ Lateral compartment LN dissection : therapeutic LN dissection

7. Materials and Methods • Mean follow-up duration : 33.8 months WIFTC : wide invasive FTC, MIFTC : minimal invasive FTC MTC : medullary thyroid cancer, HCC : Hurthle cell cancer

8. Clinicopathologicfeatures

9. Univariate statistical analysis for recurrence

10. Univariate statistical analysis for recurrence

11. Univariate statistical analysis for recurrence RAI therapy 97.9% 74.3%

12. Univariate statistical analysis for recurrence N stage 98.1% 92.6% 90.5% 67.3%

13. Multivariate statistical analysis for recurrence

14. Summary • Prognostic factors for recurrence ① Extent of thyroidectomy : no significant factor ② RAI therapy : no significant factor in multivariate analysis ③ N stage : only significant factor for recurrence in multivariate analysis - N1a : 2 riskier than N0 ( p= 0.01) - N1b : 6.7 riskier than N0 (p< 0.01) • Complication ① postoperative hoarseness : 1.9% ② permanent hypoparathyroidism : 4.5% (2.7%*~12%#) *Caliskan et al 2012 Endocrine J #Mitra et al 2011 J LaryngolOtol

15. Conclusion • Limited thyroidectomy : maybe sufficient for initial surgery for PTMC patients • Prophylactic central LN dissection : can be performed for PTMC patients for predicting prognosis accurately, : however, performed by skilled surgeon because of higher incidence of permanent hypoparathyroidism • Limitation of study : short-term follow-up duration