Preoperative Prediction of Metastatic Lymph Nodes Posterior to the Right Recurrent Laryngeal Nerve in cN0 Papillary Thyroid Carcinoma

Figures & data

Table 1 Comparison of the Clinicopathologic and US Features Between the Absence and Presence of LN-prRLN Metastasis in cN0 PTC Patients

Characteristics	LN-prRLN Metastasis (N=251)		P value
	Positive (N=45)	Negative (N=206)
Age			P=0.002*
<55 years	38 (84.4%)	125 (60.7%)
≥55 years	7 (15.6%)	81 (39.3%)
Gender			P=0.817
Male	13 (28.9%)	56 (27.2%)
Female	32 (71.1%)	150 (72.8%)
Tumor size	9.93 ± 3.35 mm	10.60 ± 2.70 mm	P=0.216
≤10 mm	21 (46.7%)	75 (36.4%)	P=0.200
>10 mm	24 (53.3%)	131 (63.6%)
Multifocality			P<0.001*
Multifocal	23 (51.1%)	44 (21.4%)
Unifocal	22 (48.9%)	162 (78.6%)
Bilaterality			P=0.624
Absent	23 (51.1%)	97 (47.1%)
Present	22 (48.9%)	109 (52.9%)
Internal component			P=0.549
Solid	44 (97.8%)	203 (98.5%)
Cystic	1 (2.2%)	3 (1.5%)
Hypo-echogenicity			P=0.586
Present	37 (82.2%)	176 (85.4%)
Absent	8 (17.8%)	30 (14.6%)
Microcalcification			P<0.001*
Present	32 (71.1%)	72 (35.0%)
Absent	13 (28.9%)	134 (65.0%)
Shape			P=0.667
Irregular	22 (48.9%)	108 (52.4%)
Regular	23 (51.1%)	98 (47.6%)
Margin			P=0.117
Ill-defined	30 (66.7%)	111 (53.9%)
Defined	15 (33.3%)	95 (46.1%)
Taller than wide			P=0.694
Present	12 (26.7%)	61 (29.6%)
Absent	33 (73.3%)	145 (70.4%)
Hashimoto’s thyroiditis			P=0.925
Concomitant	11 (24.4%)	49 (23.8%)
Non-concomitant	34 (75.6%)	157 (76.2%)
Extrathyroidal extension			P=0.622
Present	4 (8.9%)	14 (6.8%)
Absent	41 (91.1%)	192 (93.2%)
BRAF mutation			P=0.001*
Positive	38 (84.4%)	120 (58.3%)
Negative	7 (15.6%)	86 (41.7%)

Note: *Statistically significant.

Abbreviations: N, number of thyroid nodules; LN-prRLN, lymph nodes posterior to the right recurrent laryngeal nerve.

Table 2 Multivariate Logistic Regression Analysis in Predicting the LN-prRLN Metastasis in cN0 PTC Patients

PTC Characteristics	β Coefficient	Odds Ratio	95% Cl	P value
Age < 55 years	1.192	3.295	1.340–8.102	0.009*
Multifocality	0.808	2.243	1.042–4.828	0.039*
Microcalcification	1.196	3.308	1.539–7.112	0.002*
BRAF mutation	0.918	2.505	1.009–6.220	0.048*

Note: *Statistically significant.

Abbreviations: LN-prRLN, lymph nodes posterior to the right recurrent laryngeal nerve; PTC, papillary thyroid carcinoma; CI, confidence interval.

Table 3 ROC Analysis of the Independent Factors and Equation for the LN-prRLN Metastasis in cN0 PTC Patients

	Az	95% CI	Cutoff Value	Sensitivity	Specificity
Overall (N=251)
Age < 55 years	0.619	0.535–0.703	Age < 55 years	0.844	0.393
Multifocality	0.649	0.555–0.743	Multifocality	0.511	0.786
Microcalcification	0.681	0.595–0.766	Microcalcification	0.711	0.650
BRAF mutation	0.631	0.548–0.714	BRAF mutation	0.844	0.417
Predictive equation	0.780	0.712–0.848	0.213	0.622	0.786

Abbreviations: LN-prRLN, lymph nodes posterior to the right recurrent laryngeal nerve; N, number of thyroid nodules; CI, confidence interval.

Figure 1 Forest plot of the independent predictors of the LN-prRLN metastasis in cN0 PTC patients.

Abbreviation: LN-prRLN, lymph nodes posterior to the right recurrent laryngeal nerve.

Figure 2 Receiver operating characteristic (ROC) curves of (a) age < 55 years old (area under the ROC curve [AUROC] = 0.619), multifocality (AUROC = 0.649), microcalcification (AUROC = 0.638), and BRAF^V600E mutation (AUROC = 0.631), respectively. (b) Equation (AUROC = 0.780) for the prediction of the LN-prRLN metastasis.

Abbreviation: LN-prRLN, lymph nodes posterior to the right recurrent laryngeal nerve.