Threshold size criterion to suspect malignant supraclavicular lymph node < 10 mm in esophageal cancer.

OBJECTIVES

To determine the threshold size for predicting metastasis of supraclavicular lymph nodes (SCLNs) < 10 mm on axial and multiplanar reconstruction CT in esophageal squamous cell carcinoma (ESCC).

METHODS

This retrospective, multicenter study received approval from three institutional review boards, which waived informed consent. Patients with ESCC had ultrasound-guided fine-needle aspiration biopsy (US-FNAB) for SCLNs, with contrast-enhanced CT performed within 2 weeks prior to US-FNAB. A CT and ultrasound radiologist jointly analyzed images to identify and mark biopsied SCLNs < 10 mm on CT, followed by two blinded radiologists who independently measured short-axis diameter (SAD), long-axis diameter (LAD), short diameter of multiplanar reconstruction (SD-MPR), long diameter of multiplanar reconstruction (LD-MPR) and the intra-class correlation coefficient (ICC) was analyzed. Center 1 included 220 SCLNs as the training set, and Centers 2 + 3 included 75 SCLNs as the validation set. The optimal cutoff value was determined using receiver operating characteristic (ROC) curves.

RESULTS

In the training and validation sets, 31.8% (70/220) and 32.0% (24/75) of SCLNs were positive. ICC for SAD was excellent (ICC = 0.847). The area under the receiver operating characteristic curve of SAD was 0.832 in the training set, higher than others, with a cutoff value of > 6 mm, resulting in sensitivity, specificity, positive predictive value, negative predictive value, accuracy of 77.1%, 80.7%, 65.0%, 88.3%, 79.1%, respectively. In the validation set, these metrics were 87.5%, 74.5%, 61.8%, 92.7%, 81.0%, respectively.

CONCLUSION

SAD on CT can suspect metastasis of SCLN < 10 mm in ESCC patients, with a threshold size of > 6 mm.

CLINICAL RELEVANCE STATEMENT

Determining the threshold size criterion on CT images may enhance the prediction of supraclavicular lymph node metastasis in esophageal squamous cell carcinoma patients, thereby benefiting diagnostic and therapeutic strategies.

KEY POINTS

Supraclavicular lymph nodes < 10 mm in esophageal carcinoma are indeterminate for malignancy. Supraclavicular lymph nodes > 6 mm are highly suspicious for malignancy. The metastasis status of supraclavicular lymph nodes is critical for staging esophageal carcinoma.