Diagnostic Accuracy of Lymph Node Metastasis Depends on Metabolic Activity of the Primary Lesion in Thoracic Squamous Esophageal Cancer

Abstract

The metabolic activity of the primary tumor is an important variable in 18 F-FDG PET interpretation for presurgical staging, because this activity is likely to affect the possibility of detection of malignant involvement in lymph nodes (LNs). The purpose of this study was to reevaluate the diagnostic accuracy of 18 F-FDG PET/CT for the presurgical staging of esophageal squamous cell carcinoma (SCC) in correlation with the 18 F-FDG avidity of the primary lesions. Methods: One hundred fifty-six patients (mean age 6 SD, 61.4 6 8.0 y) underwent 18 F-FDG PET/CT before surgical esophagectomy and LN dissection. LN metastasis was identified using the fusion of PET and CT images with increased 18 F-FDG uptake greater than the background activity of the adjacent structures. The results of the patients' 18 F-FDG PET/CT examinations for LN involvement were compared with the histopathologic results to investigate the diagnostic accuracy of 18 F-FDG PET/CT for tumor staging. In addition, we examined the correlation between the diagnostic accuracy of 18 F-FDG PET/CT for LN involvement and the 18 F-FDG avidity of the primary lesions, to investigate the effect of tumor aggressiveness on the diagnosis of LN metastasis. Results: The diagnostic accuracy of 18 F-FDG PET/CT for LN metastasis showed a low sensitivity, ranging from 29.3% to 53.3%, whereas the specificity was higher than 89.8% in regional thoracic nodes and in remote areas of the cervical and abdominal regions. The 18 F-FDG uptake of the primary lesions positively correlated with that of the metastatic LNs in the thoracic field (R 5 0.52, P , 0.05). As a result, our receiver-operatingcharacteristic analyses demonstrated an area under the curve value of 0.73, with the optimal cutoff value at a maximum standardized uptake value of 3.3 in patients with mid to high 18 F-FDG avidity in the primary lesions (maximum standardized uptake value $ 5). Conclusion: This study showed that the avidity of the primary esophageal SCCs affected the detectability of lymph nodal metastases. If primary lesions of esophageal SCC present with a low 18 F-FDG uptake, PET/CT may have a limited role for initial staging because of low sensitivity to detect lymph node metastases.

Combination of FDG PET/CT and Contrast-Enhanced MSCT in Detecting Lymph Node Metastasis of Esophageal Cancer

“…Compared with previous literatures (Manabe et al, 2013;Li et al, 2014), both the sensitivity and the specificity of FDG PET/CT are higher in this study. The reason may be related with detecting method and poor imaging based on PET with common CT or monolayer spiral CT. Additionally, the scanning slice thickness of conventional CT is 5 mm~10 mm, and the image quality is easy to be affected by partial volume effect.…”

A study about different findings of PET-CT between neoadjuvant and non-neoadjuvant therapy: SUVmax is not a reliable predictor of lymphatic involvement after neoadjuvant therapy for esophageal cancer

“…However, if the tumor SUV max was ≤2.5, it could not provide an appropriate diagnosis value for LN metastases. We attribute this result to the assumption that FDG uptake in more advanced esophageal cancers provides better diagnostic accuracy because FDG uptake of the primary lesion is positively correlated with that of LN (10,13).…”

“…Many studies have investigated the effects of NT in terms of predicting LN metastases based on the SUV max of the primary lesions and have shown success in conditions such as hepatocellular carcinoma, breast cancer, and lung cancer (10). We showed that when LN SUV max was higher than tumor SUV max , the LN was considered to be benign regardless of SUV max in non-NT and that predicting LN metastases based on the SUV max of primary lesions was possible only in non-NT.…”

“…Thus, preoperative evaluation using PET-CT might provide unreliable information and influence the management plan for esophageal cancer (4,5,10). No definitive findings or established guidelines have been published for the evaluation of esophageal tumors (tumor) and regional LN using PET-CT in patients with esophageal cancer (2,7,8,10). In addition, it remains unclear whether PET-CT findings vary between patients treated with and without NT (2,11).…”

“…However, discrepancies between PET-CT and pathologic findings are common, especially in regional LN status. Thus, preoperative evaluation using PET-CT might provide unreliable information and influence the management plan for esophageal cancer (4,5,10). No definitive findings or established guidelines have been published for the evaluation of esophageal tumors (tumor) and regional LN using PET-CT in patients with esophageal cancer (2,7,8,10).…”