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 >10 mm 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 > 10 mm) 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 >5 mm adjacent to the primary tumor and >7 mm 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 >10 mm 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.