Early clinical esophageal adenocarcinoma (cT1): Utility of CT in regional nodal metastasis detection and can the clinical accuracy be improved?

Introduction: Treatment of early esophageal cancer depends on the extent of the primary tumor and presence of regional lymph node metastasis.(RNM). Short axis diameter>10mm is typically used to detect RNM. However, clinical determination of RNM is inaccurate and can result in inappropriate treatment. Purpose of this study is to evaluate the accuracy of a single linear measurement (short axis>10mm) of regional nodes on CT in predicting nodal metastasis, in patients with early esophageal cancer and whether using a mean diameter value (short axis+long axis/2) as well as nodal shape improves cN designation.

Methods: CTs of 49 patients with cT1 adenocarcinoma treated with surgical resection alone were reviewed retrospectively. Regional nodes were considered positive for malignancy when round or ovoid and mean size>5mm adjacent to the primary tumor and>7mm when not adjacent. Results were compared with pN status after esophagectomy.

Results: 18/49 patients had pN+ at resection. Using a single short axis diameter>10mm on CT, nodal metastasis (cN) was positive in 7/49. Only 1 of these patients was pN+ at resection (sensitivity 5%, specificity 80%, accuracy 53%). Using mean size and morphologic criteria, cN was positive in 28/49. 11 of these patients were pN+ at resection (sensitivity 61%, specificity 45%, accuracy 51%). EUS with limited FNA of regional nodes resulted in 16/49 patients with pN+ being inappropriately designated as cN0.

Conclusions: Evaluation of size, shape and location of regional lymph nodes on CT improves the sensitivity of cN determination compared with a short axis measurement alone in patients with cT1 esophageal cancer, although clinical utility is limited.