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CLN Metastasis with Papillary Thyroid Cancer in the Isthmus

Objective: To investigate the patterns and predictive factors of central lymph node metastasis in patients with papillary thyroid cancer located in the isthmus. Method: Retrospective chart review. We evaluated 447 cases with solitary nodule out of 1257 patients with papillary thyroid cancer who underwent total thyroidectomy with bilateral central lymph node compartment dissection. The patients were analyzed in 2 groups: group I, patients with cancer located in the isthmus (n = 35) and group II, patients with cancer in other regions (n = 412). We evaluated the clinicopathological characteristics and predictive factors and compared the 2 groups. Results: The frequency of central lymph node(CLN) involvement was 52.1% (233 cases) in the patients with single nodule of papillary thyroid cancer. The frequency of papillary thyroid cancer located in the isthmus was 7.8% (35 cases). Mean age at diagnosis in group I and II was 45.3 years and 46.2 years, respectively (P = .892). Size, sex, extrathyroidal extension, and ultrasound findings (eg, marked hypoechoic, taller than wide) showed no significant difference between the 2 groups. CLN metastasis in group I and group II was 62.5% and 56.5%, respectively (P = .228). Bilateral CLN metastasis was 18.8% in group I and 11.5% in the group II (P = .067). Conclusion: Papillary thyroid cancer located in the isthmus showed a tendency to involve bilateral CLN. In conclusion, it is recommended that bilateral central compartment neck dissection is needed as an appropriate surgical option for papillary thyroid cancer with single nodule located in the isthmus.