Usefulness of shear-wave elastography for detection of lymph node metastasis in esophageal and gastric cancer

Abstract

BACKGROUND

Tissue hardness is closely related to disease pathophysiology. Shear-wave elastography (SWE) is a simple and noninvasive ultrasound technique that has been used to evaluate the presence of lymph node metastases and differentiate between benign and malignant tumors.

AIM

To investigate SWE usefulness in measuring lymph node hardness to predict metastasis presence or absence in surgically removed lymph nodes.

METHODS

This observational study obtained data from patients who underwent surgery for esophageal or gastric cancer at Nippon Medical School Hospital. The hardness of the surgically removed lymph nodes was measured using SWE. The lymph nodes with hardness values ≥ 2.2 m/s were considered clinically positive for metastasis, whereas those with lower hardness values were considered clinically negative. The lymph nodes subsequently underwent pathological examination to determine the presence of metastasis, and the SWE results and pathological assessments were compared.

RESULTS

A total of 1077 lymph nodes were evaluated; 18 and 15 cases of esophageal and gastric cancer were identified, respectively. The optimal cutoff value for lymph node size was calculated to be 5.1 mm, and the area under the curve value was 0.74 (95% confidence interval: 0.69-0.84). When limited to a lymph node larger than the cut off value, the SWE sensitivity and specificity for metastasis identification were 0.76 and 0.82, respectively.

CONCLUSION

SWE was useful in detecting lymph node metastases in the upper gastrointestinal tract.

Keywords: Lymph node metastasis; Shear-wave elastography; Esophageal cancer; Gastric cancer; Tissue hardness; Ultrasonography

Core Tip: Evaluating lymph node metastasis from malignant tumors is crucial because it significantly influences treatment planning and prognosis. Shear-wave elastography is a simple, noninvasive, and objective ultrasound method for measuring tissue stiffness. In this study, the hardness of lymph nodes removed during surgery for esophageal and gastric cancer was measured using shear-wave elastography and compared with the pathological examination. The sensitivity and specificity were 0.76 and 0.82, respectively, whereas the area under the curve was 0.74 (95% confidence interval: 0.69-0.84). Shear-wave elastography was useful in detecting lymph node metastases in the upper gastrointestinal tract.