Comment on "Mapping of Lymph Node Metastasis From Esophagogastric Junction Tumors".

Abstract

To the Editor: We read the article titled “Mapping of Lymph Node Metastasis From Esophagogastric Junction Tumors” by Kurokawa et al1 published in Annals of Surgery with great interest. It is the first prospective nationwide multicenter study about Esophagogastric Junction (EGJ) tumors in the world, which may have a significant impact on treatment of EGJ tumors. We congratulate the authors on reporting a national experience on such an important issue. We would like to thank the authors for their well-designed and pioneering study. However, we still have some questions about this study. In terms of eligibility criteria, one is that tumor epicenter located within 2.0 cm of the EGJ, which is known as Nishi classification in Japan.2 But Siewert type II tumor located 1 cm above to 2 cm below the EGJ,3,4 which is universally accepted in many other countries. There is a discrepancy between 2 classification. Is Siewert classification compatible with Nishi classification for EGJ adenocarcinoma (AC)? Which classification is more reasonable? Why authors choose the Nishi classification but not Siewert classification? It is hoped that Nishi classification can be integrated with Siewert classification in the future, so as to better carry out international multicenter clinical studies and horizontally compare the clinicopathological features and efficacy of EGJ tumors. Another question is that whether it is rational that both Patients with cT2-T4 AC or squamous cell carcinoma (SSC) located within 2.0 cm of the EGJ were enrolled in the study. AC and SSC are diseases with different clinical and histological features. They originated from cardiac mucosa and squamous epithelium respectively. SCC had more invasive characteristics than AC, including more extensive esophageal invasion, deeper tumor invasion, and more advanced pathological stages.5 Due to the different histological types, locations, and esophageal invasion, the surgical treatment strategies, including surgical approach and lymph node dissection, are often different. From the data in this study, we find that 2 histological types have different metastasis rates of Lymph Node Station in both abdominal nodes and mediastinal nodes. Different extent of lymphadenectomy of AC and SSC were also recommended by the Japanese Gastric Cancer Association and Japan Esophageal Society based on the tumor location, histology and T-categories in the Japanese gastric cancer treatment guidelines 2018.6 So, it is believed that the study by Kurokawa et al would be improved by studying AC and SSC respectively. Regarding neoadjuvant treatment or not, the metastasis rates in both the abdominal nodes and mediastinal nodes are different. For example, 11d (5.2% vs 2.5%), 20 (5.2% vs 4.2%), 107 (10% vs 0%) 109L (10% vs 0%), 109R (6.7% vs 0.0%). This means those lymph nodes will be included in the category-2 nodes, which will result in different recommendation to dissect lymph nodes. Meanwhile, No. 10 lymph nodes is not involved in this study. One retrospective study has reported a high incidence (a metastasis rate of 7.6%) of EGJ tumor metastasis to No. 10 lymph nodes.7 It is still a controversial issue whether dissect No. 10 lymph nodes or not in the EGJ tumors and gastric cancer.7–9 Also, we think that the inclusion criteria of age for the enrolled patients were not entirely reasonable, because the maximum patient age is 90 years, which means that lots of elderly patients were also included in this trial. Of course, there are different definitions of elderly in different countries and areas. The range of enrolled patients’ age is 27–90, which may indicates that the long-term effect of lymph node dissection for EGJ cancer might therefore not be evaluable for such elderly patients. There are still too many disputes about the classification of EGJ tumor, Tumor, Node, Metastasis (TNM) staging, the choice of surgical approach, the scope of lymph node dissection, digestive tract reconstruction and perioperative adjuvant therapy. We are looking forward to combine with the database analysis of large samples of eastern and western cases can provide us with more accurate recommendation and standards in the future.