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Comment on "Randomized Controlled Trial to Evaluate Splenectomy in Total Gastrectomy for Proximal Gastric Carcinoma".

To the Editor: We read with great interest the excellent research titled ‘‘Randomized Controlled Trial to Evaluate Splenectomy in Total Gastrectomy for Proximal Gastric Carcinoma’’ by Sano et al published in Annals of Surgery. The authors evaluated the long-term survival and surgical outcomes between splenectomy and spleen preservation in total gastrectomy for proximal gastric cancer. They showed that in total gastrectomy for proximal gastric cancer that does not invade the greater curvature, splenectomy should be avoided as it increases operative morbidity without improving survival. We would like to thank the authors for their well-designed and pioneering study. However, we have several concerns regarding some key points that should be detailed to fully understand the reported results and their interpretation. First, this study includes tumors invading the esophagus if the invasion was 3 cm or shorter. In their opinion, that was because the RCT (JCOG 9502) had shown that these tumors should be treated not by thoracotomy but by an abdominal approach, which was standard in this splenectomy trial. However, in Japanese gastric cancer treatment guidelines 2014 (ver. 4), these tumors invading the esophagus less than 3 cm could be classified as junctional cancer, which the No. 10 lymph nodes (LN) is not the extent of lymphadenectomy for junctional cancer. On the other hand, in the guidelines for tumors invading the esophagus, D2 lymphadenectomy should include Nos. 19, 20, 110, and 111. So the treatments of these patients with tumors invading the esophagus were different with proximal gastric cancer without esophagus invading. Second, as shown in the clinicopathological features, the pathological T category and histology type were different in splenectomy and spleen preservation groups. The splenectomy group has less pT1 patients and more T3 cases (tumor penetration of serosa in this study according to the 6th edition of UICC/TNM system), and moreover, more undifferentiated type. These unfavorable factors may affect the survival of splenectomy group. The knowledge of comparison between these factors, and matching them for some balance would be beneficial. Third, in spleen preservation group D2 lymphadenectomy was performed except the No. 10 dissection (some were dissected if judged easily removable in lean patients). However, in the splenectomy group, the No. 10 LNs were dissected during the splenectomy. In total, 8 of 312 patients who with No.10 lymphadenectomy had histological metastasis in No.10 nodes (the metastasis rate was only 2.6%). Lastly, the overall survival and relapse-free survival showed a similar result. Does this mean that it is not necessary to perform No.10 lymphadenectomy for proximal gastric cancer without involving the greater curvature? Overall, this is a well-written randomized controlled trial regarding an important clinical problem. Clarifying above concerns would provide useful and valuable data to the readers.