목적: Papillary thyroid carcinoma (PTC) is generally an indolent tumor indicative of favorable prognosis. However, invasive PTC may be relatively recurrent after treatment and its management has not been firmly established. We therefore evaluated treatment outcomes after definitive surgery for locally invasive well-differentiated PTC. 방법:This study included 62 consecutive patients who underwent definitive surgery and radioactive iodine therapy or radiotherapy for non-distant metastatic invasive PTC. Clinical factors, operative and pathologic findings, surgical morbidity, and recurrences were examined.Univariate and multivariate analyses were performed to identify factors associated with recurrence-free survival (RFS) and overall survival (OS) after treatment. 결과:Invasion to the recurrent laryngeal nerve (RLN), trachea, esophagus, and larynx were found in 42 (68%), 40 (65%), 14 (23%), and 7 (3%) patients, respectively, and lymph node metastasis were found in 51 (81%) patients. Biochemical complete remission(stimulated thyroglobulin < 1 ng/mL) was achieved in 53 (85%) patients after treatment. Permanent vocal fold paralysis (of patients without preoperative paralysis) and hypoparathyroidism developed in 13/41 (32%) and 5/62 (8%) patients, respectively. During a median follow-up of 63 months, 14 (22.5%) patients had recurrences including 7 (11%) distant recurrences. Univariate analyses showed that lateral cervical nodal metastasis (P = 0.001), macroscopic extranodal extension (ENE, P< 0.001), as well as stimulated (P =0.001) and unstimulated (P =0.005) serum thyroglobulin were significant predictors of RFS. Multivariate analyses showed that macroscopic ENE and biochemical remissionindependently predicted RFS (P<0.005). 결론:Our data suggest locally-invasive PTC is associated with high rate of metastasis and recurrence, leading to poor survival outcomes. Macroscopic ENE and postoperative thyroglobulin levels may guide to select the patients requiring intensive surveillance.