Do radioiodine-avid lymph nodes from differentiated thyroid cancer on the initial posttherapy scan need repeated 131I therapy?

Yongji Jiang; Simin Liu; Xiaotong Qiu; Yanlei Huo; Xiaoying Zhang; Haidong Cai; Zhongwei Lv; Chao Ma

doi:10.3389/fendo.2023.1099449

Do radioiodine-avid lymph nodes from differentiated thyroid cancer on the initial posttherapy scan need repeated ¹³¹I therapy?

Front Endocrinol (Lausanne). 2023 May 30:14:1099449. doi: 10.3389/fendo.2023.1099449. eCollection 2023.

Authors

Yongji Jiang¹, Simin Liu¹, Xiaotong Qiu¹, Yanlei Huo¹, Xiaoying Zhang¹, Haidong Cai¹, Zhongwei Lv¹, Chao Ma¹

Affiliation

¹ Department of Nuclear Medicine, Shanghai Tenth People's Hospital, School of Medicine, Tongji University, Shanghai, China.

Abstract

Background: Residual/recurrent lymph node metastase (LNM) is often found after differentiated thyroid cancer (DTC) surgery. This study aimed to investigate whether patients complicated with radioiodine-avid (¹³¹I+) lymph nodes from DTC on the initial posttherapy scan (PTS) need repeated ¹³¹I therapy.

Methods: From June 2013 to August 2022, DTC patients with ¹³¹I+ lymph nodes on the initial PTS who received at least two cycles of ¹³¹I therapy were retrospectively enrolled. They were divided into a complete response (CR) group and an incomplete response (IR) group according to their response to the initial ¹³¹I therapy based on the 2015 American Thyroid Association (ATA) guidelines.

Results: A total of 170 DTC patients with ¹³¹I+ lymph nodes on the initial PTS were included; 42/170 (24.7%) patients were classified into the CR group and 128/170 (75.9%) were classified into the IR group according to their response to the initial ¹³¹I therapy. None of the 42 CR patients had disease progression at the subsequent follow-up, and 37/170 (21.8%) IR patients improved after repeated therapy. Univariate analysis showed that N stage (P=0.002), stimulated thyroglobulin (sTg) level before initial ¹³¹I therapy (P<0.001), LNM size (P<0.001), number of total residual/recurrent LNM (P=0.021), radioiodine-nonavid (¹³¹I-) LNM (P=0.002) and ultrasound features (P<0.001) were related to the initial treatment response. On multivariate analysis, sTg level (OR=1.186, P<0.001) and LNM size (OR=1.533, P=0.004) were independent risk factors for IR after initial ¹³¹I therapy. The optimal sTg level and LNM size cutoff value for predicting the treatment response after initial ¹³¹I therapy were 18.2 µg/l and 5mm.

Conclusion: This study suggested that approximately one-quarter of patients with ¹³¹I+ lymph nodes on initial PTS, especially those with N0 or N1a stage, lower sTg level, smaller LNM size, ≤2 residual/recurrent LNMs, negative ultrasound features and no ¹³¹I- LNM, remain stable after one cycle of ¹³¹I therapy and do not need repeated therapy.

Keywords: 131I therapy; differentiated thyroid cancer (DTC); lymph node metastasis; posttherapy scan; treatment response.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adenocarcinoma* / pathology
Humans
Iodine Radioisotopes / therapeutic use
Lymph Nodes / diagnostic imaging
Lymph Nodes / pathology
Retrospective Studies
Thyroid Neoplasms* / diagnostic imaging
Thyroid Neoplasms* / pathology
Thyroid Neoplasms* / radiotherapy

Substances

Iodine Radioisotopes

Grants and funding

This work was supported by the National Natural Science Fund (grant number: 82171974), the Shanghai Health Bureau Fund (grant number: 202040085), Shenkang medical enterprise integration innovation collaboration special Fund (grant number: SHDC2022CRT023), and Shanghai Shenkang Three-year Action Project (grant number: SHDC2020CR2054B).