A Comparison of Two Operation Methods Revealed the Risk Factors and the Necessity of LN-prRLN Dissection in Papillary Thyroid Carcinoma: A Retrospective Cohort Study in FUSCC

Abstract

Background. Although the American Thyroid Association (ATA) guidelines indicate that central lymph nodes posterior to the right recurrent laryngeal nerve (LN-prRLN) should be routinely dissected, pr-RLN dissection is often neglected due to the high risk of injury to the recurrent laryngeal nerve (RLN). The purpose of this study was to investigate the risk factors associated with LN-prRLN metastasis in patients with papillary thyroid carcinoma (PTC) by preoperative examination and the indications for LN-prRLN dissection. Methods. A total of 1487 consecutive patients with PTC who underwent total thyroidectomy or right lobectomy plus isthmic resection with central LN dissection (CLND) were divided into two groups: patients with LN-prRLN dissection (group A) and patients without LN-prRLN dissection (group B). Clinicopathologic data were reviewed of the patients who were operated on by the same thyroid surgery team in the Department of Head Neck Surgery, Fudan University Shanghai Cancer Center (FUSCC) between August 2011 and May 2019. The relationships of LN-prRLN metastasis with clinicopathologic characteristics were analyzed by univariate and multivariate logistic regression. Results. The incidence of LN-prRLN metastasis was 34.1% (129/378). Univariate analysis showed that sex (P≤0.001), tumor size (P≤0.001), extrathyroidal extension (P=0.002), concurrent Hashimoto’s thyroiditis (P=0.009), cLNMa (central lymph nodes anterior to the right recurrent laryngeal nerve) (P≤0.001), cLNMa number (P≤0.001), and lateral LN metastasis (LLNM) (P≤0.001) were significantly associated with LN-prRLN metastasis in PTC. Multivariate logistic regression analysis revealed that tumor size (P=0.039), cLNMa (P=0.001), and LLNM (P=0.025) were independent risk factors for LN-prRLN metastasis in patients with PTC. Although there was no significant difference between the two groups in recurrence, we found that 4 cases relapsed in the LN-prRLN compartment in group B, while none relapsed in group A. Conclusion. LN-prRLN metastasis is often identified in patients with PTC. Patients with large tumor sizes, cLNMa and LLNM are at a high risk of LN-prRLN metastasis and should be recommended for careful LN-prRLN dissection.

Prediction and applications of lymph nodes posterior to the right recurrent laryngeal nerve metastasis in patients with papillary thyroid carcinoma

“…Tumor size played an important role in LN-prRLN metastasis and was indicated as an independent risk factor of LN-prRLN metastasis in almost all reported models [12,22,23,[25][26][27]. In our study, we found that tumor size is positively correlated with LN-prRLN metastasis, and tumor size > 10mm was an independent predictor for LN-prRLN metastasis.…”

Metastasis of cN0 Papillary Thyroid Carcinoma of the Isthmus to the Lymph Node Posterior to the Right Recurrent Laryngeal Nerve

“…The safety of LN-prRLN dissection is a point of concern. Wang et al (11) divided 1487 patients into two groups: the 378 patients who underwent CND with LN-prRLN dissection were defined as group A and the 1109 patients who underwent CND without LN-prRLN dissection as group B. Although group A had a higher incidence of hypocalcemia (7.4% vs. 4.0%, P=0.012), the two groups had similar rates of persistent hypocalcemia, transient and permanent recurrent laryngeal nerve palsies, chyle leakages, hematomas, and wound infections.…”

“…However, there is increasing evidence that LN-prRLN metastases can occur in up to 26.6% of cN0 PTCs and that an additional removal procedure is not associated with an increased possibility of transient or permanent hypoparathyroidism or vocal cord paralysis (9)(10)(11)(12)(13)(14)(15). Common risk factors for LN-prRLN metastases include multiple foci, extrathyroidal extensions (ETE), right lobe tumors, tumor size, LN-arRLN metastases, and the number of positive LNs in the central neck.…”

“…Common risk factors for LN-prRLN metastases include multiple foci, extrathyroidal extensions (ETE), right lobe tumors, tumor size, LN-arRLN metastases, and the number of positive LNs in the central neck. However, these finding were based on studies that included only patients with PTCs located in the right lobe (9) or with PTC, irrespective of tumor site (7,(10)(11)(12). Studies on patients with PTCs located in the isthmus had very limited sample sizes (13)(14)(15).…”

Carbon nanoparticle-guided intraoperative lymph node biopsy predicts the status of lymph nodes posterior to right recurrent laryngeal nerve in cN0 papillary thyroid carcinoma

“…According to published studies, the incidence of LN-prRLN metastasis was 17. predictors such as age, male gender, tumor diameter, capsular invasion, comorbid adenoma, Hashimoto's thyroiditis, and VIa compartment lymph nodes metastasis were considered to be significantly associated with LN-prRLN metastasis (15)(16)(17)(18)(19)(20)(21)(22). Our center's data revealed that the incidence of LN-prRLN metastasis was 15.9%, but our multivariate analysis suggested that none of the indicators mentioned above were good predictors for the status of LN-prRLN.…”