Int J Thyroidol.  2016 Nov;9(2):159-167. 10.11106/ijt.2016.9.2.159.

Pathological N1b Node Metastasis Itself Can Be Still a Valid Prognostic Factor in PTC after High Dose RAI Therapy

• Kim CY
• Son SH
• Jung JH
• Lee CH
• Jeong JH
• Jeong SY
• Lee SW
• Ahn BC
• Lee J

• KMID: 2362352
• DOI: http://doi.org/10.11106/ijt.2016.9.2.159

Abstract

BACKGROUND AND OBJECTIVES
The aim of this study was to determine whether pathologically proven central or lateral lymph node (LN) metastasis (pN1a or pN1b) could affect ablation success and recurrence after high-dose radioactive iodine (RAI) ablation. We also sought to identify the risk factors for long-term recurrence in patients with papillary thyroid carcinoma (PTC).
MATERIALS AND METHODS
A total of 277 patients with pN1 disease who had undergone high-dose RAI ablation (5.55 GBq) between 2000 and 2006 were included in this retrospective study. We compared the ablation success rate and the recurrence rate between patients with pN1a and pN1b disease. Univariate and multivariate analyses were performed to identify the risk factors for recurrence.
RESULTS
The median duration of follow-up was 10.2 years. The overall ablation success rate was 64%, and the ablation success rate in the pN1b group (49%) was lower than in the pN1a group (74%). The overall recurrence rate was 23%, and the recurrence rate in the pN1b group (30%) was higher than in pN1a group (18%). A higher ratio of metastatic LNs, a higher level of pre-ablation thyroglobulin, and ablation failure were significant risk factors for recurrence by multivariate analysis.
CONCLUSION
Patients with pN1b disease experienced a lower ablation success rate and a higher recurrence rate than patients with pN1a disease. However, a higher ratio of metastatic LNs, a higher level of pre-ablation thyroglobulin, and ablation failure were stronger risk factors than the pathological N stage for long term recurrence in patients with node-positive PTC.

Keyword

Papillary thyroid carcinoma; Ablation success; Recurrence; Radioactive iodine ablation

MeSH Terms

Follow-Up Studies
Humans
Iodine
Lymph Nodes
Multivariate Analysis
Neoplasm Metastasis*
Recurrence
Retrospective Studies
Risk Factors
Thyroglobulin
Thyroid Neoplasms
Iodine
Thyroglobulin

Figure

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  Fig. 1. Comparison of ablation success rate between patients with papillary thyroid carcinoma who had pathological N1a and N1b disease.

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  Fig. 2. Comparison of recurrence rate between patients with papillary thyroid carcinoma who had pathological N1a and N1b disease.

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  Fig. 3. Kaplan-Meier survival analysis according to patholo-gical N1a and N1b disease in patients with papillary thyroid carcinoma.

Reference

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