Korean J Endocr Surg.  2015 Sep;15(3):67-72. 10.16956/kaes.2015.15.3.67.

The Prognostic Significance of the Metastatic Lymph Node Ratio in Patients with Papillary Thyroid Carcinoma

• Kang SY
• Kim SK
• Youn HJ
• Jung SH

• KMID: 2233903
• DOI: http://doi.org/10.16956/kaes.2015.15.3.67

Abstract

PURPOSE
Metastatic lymph node ratio (MLNR) is known as an important prognostic factor in many solid carcinomas; however, the role of MLNR in papillary thyroid carcinoma (PTC) is unclear. The purpose of this study was to determine whether MLNR has prognostic significance for recurrence in patients with pathological N1a PTC.
METHODS
A retrospective analysis was conducted of 1,198 patients with PTC who underwent total thyroidectomy with central neck dissection between 2006 and 2011. Only patients with central lymph node metastasis were included in this study. Patients with lateral neck lymph node metastasis or extrathyroidal involvement were excluded. Finally, this study included 282 patients with N1a patients. MLNR was defined as the number of metastatic lymph nodes divided by the number of removed lymph nodes.
RESULTS
Median age was 47.3 years (17~73 years). There were 209 female patients and 41 male patients, respectively. Median follow-up period was 53 months (36~114 months). Median value of MLNR was 0.36 (0.04~1.000). Of 250 patients, 20 patients (8.0%) developed recurrent disease. MLNR independently predicted PTC recurrence (odds ratio [OR], 6.385; 95% confidence interval [CI], 2.523-16.158; P < 0.001). In receiver operating characteristic curve analysis, 0.47 was significantly meaningful for recurrence when three or more lymph nodes were collected.
CONCLUSION
MLNR is an independent predictor of PTC recurrence in patients with pathological N1a PTC. Therefore, N1a patients with MLNR > 0.47 should be monitored closely for recurrence.

Keyword

Thyroid carcinoma; Lymph node; Ratio; Recurrence

MeSH Terms

Female
Follow-Up Studies
Humans
Lymph Nodes*
Male
Neck
Neck Dissection
Neoplasm Metastasis
Recurrence
Retrospective Studies
ROC Curve
Thyroid Gland*
Thyroid Neoplasms*
Thyroidectomy

Figure

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  Fig. 1 Description of study cohort. A total of 250 patients were enrolled in this study.

• 

  Fig. 2 Recurrence-free survival curves according to metastatic lymph node ration (MLNR) in patients with pN1a papillary thyroid carcinoma. There was a significant difference between patients with MLNR 0.47 and ≥ 0.47 (P<0.001).

• 

  Fig. 3 In tumor size ≤1 cm group and 1 cm 2 cm group (P=0.386) (C).

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