ScholarWorks@중앙대학교

초록

Differentiated thyroid cancer (DTC) has a favorable prognosis. As indeterminate nodes are common, distinguishing recurrent and persistent DTC remains challenging. Previous studies have not specifically focused on prognosis between recurrent and persistent DTC. Thus, we aimed to compare prognosis and oncologic characteristics of two groups. This retrospective cohort study was conducted at a single tertiary care institution, enrolling 265 patients (recurrent: 109, persistent: 156) who underwent re-operation from November 1, 1999 to August 31, 2018 due to structural diseases. Those with distant metastasis at the time of initial diagnosis were excluded. Clinical and oncologic characteristics, patterns of lymph node (LN) metastasis, disease-free survival (DFS), and overall survival (OS) were compared between two groups. The time zero used for DFS is the time of the second operation. Recurrent DTC exhibited higher incidence of central LN metastasis (p-value = 0.003), infield recurrence (p-value < 0.001), and distant metastasis (p-value < 0.001). In contrast, persistent DTC showed more lateral LN metastasis (p-value = 0.003) and outfield recurrence (p-value < 0.001). The most common site of neck LN metastasis was ipsilateral level VI/VII (51.4%) for recurrent DTC and ipsilateral level IV (43.0%) for persistent DTC. Ten-year DFS was significantly lower for recurrent DTC (41.0%) than for persistent DTC (67.9%) (p-value < 0.001). Recurrent DTC, older age, higher total metastatic LN at the second operation (first re-operation), and R1/R2 resection at the second operation were associated with decreased DFS. OS isn't significantly different between recurrent and persistent DTC (p-value = 0.160). : Recurrent DTC has poorer DFS than persistent DTC, although OS isn't significantly different.

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