The stratification of patient risk depending on the size and ratio of metastatic lymph nodes in papillary thyroid carcinoma

Abstract

Abstract Background The aims of this study were to identify the clinical significances of the size of metastatic lymph node (mLN) and LN ratio (LNR) and to attempt to create a risk stratification for papillary thyroid carcinoma (PTC) patients. Methods We investigated the 435 PTC patients who underwent radioactive iodine (RAI) ablation treatment following thyroid surgery. The patients were classified into two groups (micrometastasis (pN1mic) ≤ 0.2 cm and macrometastasis (pN1mac) > 0.2 cm) and were stratified into the following three risk groups: group I (pN1mic, LNR ≤ 0.5); group II (pN1mic, LNR > 0.5 or pN1mac, LNR ≤ 0.5); and group III (pN1mac with LNR > 0.5). And then we investigated the association of the classified groups and variable clinicopathologic factors. Results The clinical characteristics such as large tumor size, extrathyroidal extension, higher T stage, and greater number of mLN or LNR were significantly associated with pN1mac. The mean stimulated thyroglobulin levels were increased with the patient risk groups (p = 0.02). The recurrence-free survivals were significantly different between the stratified groups (p = 0.001). Conclusions The patient groups I, II, and III may be referred to as low-, intermediate-, and high-risk groups. Clinicians should consider the possibility of recurrence, and the decisions about the application of RAI ablation based on the size of mLN and the patient’s risk groups.

Keywords

• Risk stratification
• Prognosis
• Lymph node size
• Ratio of lymph node
• Papillary thyroid carcinoma