Risk Factor Analysis for Central Lymph Node Metastasis in Papillary Thyroid Microcarcinoma

Abstract

Purpose

Although the prognosis of papillary thyroid microcarcinoma (PTMC) is excellent, cervical lymph node metastasis (CLNM) is commonly observed in PTMC. This study aimed to investigate the incidence and risk factors for CLNM in PTMC.

Patients and Methods

Altogether, 687 patients with PTMC who initially underwent unilateral thyroidectomy with unilateral central lymph node dissection or bilateral thyroidectomy with bilateral central lymph node dissection between January 2014 and June 2018 at our hospital were included. The patients were divided into two groups: PTMC with CLNM and PTMC with no CLNM. The clinicopathologic characteristics and ultrasound features were compared between the groups. Univariate and multivariate logistic regression analyses were used to identify the risk factors for CLNM.

Results

CLNM was observed in 121/687 (17.6%) patients with PTMC. PTMC patients aged <55 years exhibited a greater incidence of CLNM (87.6% vs 12.4%) than those aged ≥55 years. PTMC patients with CLNM were more likely to have capsular extension (24.0% vs 15.4%) and extension to the adjacent structures (9.9% vs 4.2%). Patients with microcalcification on ultrasound images were more likely to have CLNM (66.1% vs 47.9%). Multivariate logistic regression analysis revealed that microcalcification (odds ratio [OR]: 2.066, 95% confidence interval [CI]: 1.361–3.135, P<0.001), age <55 years (OR: 2.341, 95% CI: 1.309–4.187, P=0.004), capsular invasion (OR: 1.772, 95% CI: 1.082–2.879, P=0.023), and invasion of the adjacent tissues (OR: 2.872, 95% CI: 1.355–4.187, P=0.004) were significant risk factors for CLNM.

Conclusion

Microcalcification, age <55 years, capsular invasion, and invasion of the adjacent tissues were significant risk factors for CLNM in PTMC.

Graphical Abstract

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Keywords:

• risk factors
• papillary thyroid microcarcinoma
• microcalcification
• age
• invasion

Abbreviations

PTMC, papillary thyroid microcarcinoma; PTC, papillary thyroid carcinoma; US, ultrasound; CLNM, central lymph node metastasis; AJCC, American Joint Committee on Cancer; OR, odds ratio; CI, confidence interval.

Code Availability

The code used or analyzed during the current study are available from the corresponding author on reasonable request.

Data Sharing Statement

The datasets used or analyzed during the current study are available from the corresponding author on reasonable request.

Ethics Statement

This study was conducted with the approval of the Ethics Committee of Shanghai Jiao Tong University Affiliated Sixth People’s Hospital and in accordance with the declaration of Helsinki. Written informed consent was obtained from all participants.

Acknowledgments

The authors would like to thank all the reviewers who participated in the review.

We would like to thank Editage (www.editage.com) for English language editing.

Disclosure

The authors report no conflicts of interest.

Additional information

Funding

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.