Thyroid cancer (TC) is one of the most common endocrine tumors in the head and neck. In recent years, the incidence rate of TC has increased year by year. Papillary thyroid carcinoma (PTC) is the most common pathological type, which accounts for 80% [
A total of 844 patients with PTC, who were surgically treated and diagnosed by histopathology at the First People’s Hospital of Foshan and People’s Hospital of Nanhai District, Foshan, between January 2016 and February 2021, were enrolled. They consisted of 268 (31.8%) males and 576 (68.2%) females aged from 11 to 84 years with an average of 41.98 ± 12.77 years. The maximum diameter of the nodules was 16.43 ± 11.07 mm (range: 3–94 mm). This study was approved by the First People’s Hospital of Foshan and People’s Hospital of Nanhai district, Foshan. An informed consent form was signed by all the patients, and patients who had relative contraindications were excluded. Inclusion criteria were as follows: (i) thyroid surgery was performed for the first time, and the postoperative pathology was PTC, (ii) central lymph node dissection was performed, and (iii) there was no history of other malignant tumors.
Ultrasonic examinations were performed with Yum MyLab Class C and GE Logiq 9 sonographic scanners equipped with high-frequency, 5e12-MHz linear probes. Data were collected about the sex and age of the patients and size and location of the thyroid nodules. The ultrasound images were analyzed retrospectively by two doctors with more than 5 years of experience in thyroid diagnosis.
According to the TI-RADS classification, the following ultrasound features of the nodule were recorded: composition, echo, aspect ratio, margin, and calcification. Scores were assigned according to the degree of each ultrasound feature. The final scores were added to calculate the total TI-RADS score, and in case of disagreements, the results were approved after discussion.
Statistical analyses were performed using SPSS version 22.0. Mean ± standard deviation was used to express normal distribution of measurement data (age, maximum diameter, and TI-RADS score). Two independent-sample
844 patients with PTC were divided into the CLNM and nonmetastasis group by postoperative histopathology. 439 patients in the CLNM group had a metastasis rate of 52% (439/844) and consisted of 166 (37.8%) males and 273 (62.2%) females. The mean TI-RADS score was 9.42 ± 2.262, which was higher than that in the group without CLNM (
Single-factor analysis of lymph node metastasis in the central area of PTC.
Term | CLNM | |||
---|---|---|---|---|
Positive ( | Negative ( | |||
Gender | 15.502 | <0.001 | ||
Male | 166 | 102 | ||
Female | 273 | 303 | ||
Age (years) | 3.045 | 0.069 | ||
≤45 | 292 | 245 | ||
>45 | 147 | 160 | ||
Location | 28.972 | <0.001 | ||
Upper | 51 | 96 | ||
Middle | 236 | 219 | ||
Lower | 242 | 90 | ||
Mulifocality | 19.322 | <0.001 | ||
Solitary | 247 | 287 | ||
Multifocal | 192 | 118 | ||
Maximum diameter of the nodule | 18.42 ± 12.057 | 14.28 ± 9.458 | −5.572 | <0.001 |
TI-RADS total score | 9.42 ± 2.262 | 8.32 ± 2.819 | −6.211 | <0.001 |
CLNM: central lymph node metastasis.
Sex, location, multifocality, shape, margin, calcification, maximum diameter of the nodule, TI-RADS total score, and CLNM had a significant relationship (
Single-factor analysis of lymph node metastasis in the central area of PTC.
Term | CLNM | |||
---|---|---|---|---|
Positive ( | Negative ( | |||
Composition | 1.09 | 0.58 | ||
Cystic | 0 | 1 | ||
Spongy nodules | 0 | 0 | ||
Mixed nodules | 20 | 18 | ||
Substantial or almost substantial | 419 | 386 | ||
Echo | 4.431 | 0.219 | ||
No echo | 1 | 0 | ||
Highly echoic | 26 | 18 | ||
Low echo | 323 | 370 | ||
Very low echo | 55 | 51 | ||
Shape | 15.25 | <0.001 | ||
Wider than tall | 294 | 218 | ||
Taller than wide | 145 | 187 | ||
Margin | 83.186 | <0.001 | ||
Smooth | 3 | 31 | ||
Owed | 102 | 170 | ||
Irregular/lobed | 107 | 98 | ||
External invasion | 227 | 106 | ||
Calcification (multiple choice) | 55.164 | <0.001 | ||
Without or with comet tail sign | 82 | 166 | ||
Coarse | 25 | 25 | ||
Peripheral (circular) | 9 | 11 | ||
Punctate echo | 308 | 191 | ||
Coarse + surrounding | 1 | 1 | ||
Coarse + punctate strong echo | 14 | 11 |
Eight factors with statistical significance in the univariate analysis were included in the multivariate logistic regression analysis. The results showed that the larger the nodule diameter and the higher the TI-RADS score, the higher the risk of CLNM, which was statistically significant (OR = 1.022, 95% CI 1.006–1.038,
Multivariate analysis of lymph node metastasis in the central area of PTC.
B | S. E | Wals | Sig. | Exp (B) | 95% CI | ||
---|---|---|---|---|---|---|---|
Sex | Male | 0.609 | 0.172 | 12.575 | 0.01 | 1.839 | 1.313–2.575 |
Female | |||||||
Location | Upper | 21.147 | 0.01 | ||||
Middle | −1.115 | 0.243 | 21.100 | 0.01 | 0.328 | 0.204–0.528 | |
Lower | −0.396 | 0.184 | 4.606 | 0.032 | 0.673 | 0.469–0.966 | |
Maximum diameter | 0.022 | 0.008 | 7.643 | 0.006 | 1.022 | 1.006–1.038 | |
Shape | 1.491 | 0.241 | 38.307 | 0.01 | 4.443 | 2.771–7.125 | |
Margin | Smooth | 7.017 | 0.071 | ||||
Owed | −1.555 | 0.679 | 5.250 | 0.022 | 0.211 | 0.056–0.799 | |
Irregular/lobed | −0.269 | 0.241 | 1.250 | 0.264 | 0.764 | 0.477–1.225 | |
External invasion | −0.341 | 0.200 | 2.912 | 0.088 | 0.711 | 0.480–1.052 | |
TI-RADS score | 0.307 | 0.056 | 30.543 | 0.01 | 1.359 | 1.219–1.516 | |
Multifocality | 0.507 | 0.165 | 9.373 | 0.002 | 1.660 | 1.200–2.296 |
The central area of the lymph nodes is the first area of PTC metastasis. It has been reported that the metastasis rate is 20%–90% [
The metastasis rate of CLNM in this study was 52%, which was consistent with the previously reported metastasis rate of 38%–60.9% [
The incidence rate of PTC in females is higher than that in males, but males are more likely to develop CLNM [
This study included more females (62.2%) than males (37.8%) in CLNM (
A considerable number of studies have confirmed that CLNM is closely related to the size of nodules and the risk of metastasis increases with the increase in its size [
Our study observed that extranodal invasion was 51.7% (227/439) and irregular/lobular shape was 24.4% (107/439) in the CLNM group. Different manifestations of nodular margins have a statistically significant effect on CLNM, which is consistent with relevant studies [
The central lymph nodes are located between the hyoid bone and sternum, over the trachea close to the thyroid. Owing to their deep location, the sensitivity and specificity of ultrasound for the diagnosis of CLNM are low [
Papillary thyroid carcinoma with central lymph node metastasis. The tumor is located in the middle and lower poles of the left thyroid lobe. The maximum diameter is 40 mm. It is solid and very hypoechoic with an aspect ratio <1, external invasion, internal visible hyperechoic small calcification, and American College of Radiology Thyroid Imaging Reporting and Data System (ACT TI-RADS) score of 11 points. (a) Transverse section and (b) longitudinal section.
Ultrasonography of the nodules in papillary thyroid carcinoma (PTC) without central lymph node metastasis. The tumor is located in the middle of the left thyroid lobe, with a maximum diameter of 8 mm, solid and very hypoechoic, aspect ratio >1, and unclear margin. The American College of Radiology Thyroid Imaging Reporting and Data System (ACT TI-RADS) score was 8 points. (a) Transverse section; (b) longitudinal section.
This study had some limitations. Since it was a retrospective analysis, there were some confounding factors. Scoring and classification based on static two-dimensional images of the nodules reduced the accuracy to a certain extent, leading to possible deviations in the results.
In summary, the results of this study indicated that female, maximum diameter of the nodule, multifocality, a taller-than-wide shape, and high TI-RADS score were the independent risk factors for CLNM. When scoring the nodule with TI-RADS during ultrasonic examination, we can predict whether there is CLNM or not in combination with size, shape, multifocality, etc., which can provide the clinicians with the reference basis for a surgical approach.
The data used to support the findings of this study are available from the corresponding author upon request.
Minying Zhong and Zhaoming Zhang are the first authors. Weijun Huang and Liping Lu are the corresponding authors.
The authors declare no conflicts of interest.
Minying Zhong and Liping Lu designed the study. WeiJun Huang, Yongyu Chen, and Liping Lu provided the databases. Minying Zhong, Yisheng Xiao, and Yanping He assembled and analyzed the data. Minying Zhong, WeiJun Huang, and Zhaoming Zhang drafted the article, and Minying Zhong and Zhaoming Zhang critically revised the article for important intellectual content. WeiJun Huang gave final approval of the version to be published. All authors read and approved the final manuscript. Liping Lu and WeiJun Huang contributed equally to this work.