Recently, the results of EUS-ELTI have been reported in many papers. Although many advantages are expected from this procedure, some procedure-related adverse events and postprocedural inflammatory processes, including severe pancreatitis and severe inflammatory adhesions can develop on surrounding organs such as the stomach, colon, spleen, and blood vessels. These inflammatory processes make the subsequent surgery after EUS-ELTI treatment difficult, requiring extensive resection, disabling the preservation of the pancreatic parenchyma or adjacent organs. Finally, it makes it difficult to perform minimally invasive surgery. The advantages of minimally invasive laparoscopic pancreatectomy, such as distal pancreatectomy and pancreaticoduodenectomy for benign and low-grade malignant diseases, are well-known, including reports based on our center.[12, 14, 15] However, no study has been reported on the surgical outcomes after the failure of EUS-ELTI treatment.
Among the 23 patients who underwent surgical resection after EUS-ELTI treatment, 18 patients had operative findings of severe adhesion and inflammation. These findings made the operation difficult and caused many postoperative adverse events. In fact, almost all patients had procedure-induced pancreatitis and underwent open surgery for the treatment of lesions after EUS-ELTI. In general, pancreatic cystic tumors are usually suitable for minimally invasive surgery irrespective of the location of the lesions. Among the 23 patients in this series, however, only 12 patients (52.1%) could undergo laparoscopic surgery. In addition, all patients with pancreatic head lesions underwent an open pancreaticoduodenectomy. If patients chose surgical resection as the initial treatment of cystic tumors in the pancreas, they could undergo laparoscopic surgery in all cases, irrespective of the location of the lesion.
When distal pancreatectomy is performed in benign cystic lesions, spleen preservation is very important for the patient. The prevalence of overwhelming post-splenectomy infections in adults was reported to be 0.8–1.9%, and this significant rate cannot be ignored, especially in old or immunocompromised patients. Many studies reported that spleen preservation decreased the rate of surgical site infection and improved short-term prognosis.[1, 13] In the present study, among 15 patients who underwent distal pancreatectomy (open or laparoscopic), the spleen could be preserved in only two patients (13.3%). Among 12 patients who underwent LDP, the spleen could be preserved in only one patient (8.3%). In our data on laparoscopic pancreatectomy, the spleen could be preserved in 72% (587 of 815) of the patients with benign pancreatic lesions. If the patients chose a minimally invasive surgery as the initial treatment, the spleen could have a higher chance of preservation.
Interestingly, in the present study, when the lesions were in the far tail of the pancreas, the possibility of additional surgery was higher (20%, 5 of 20) than when they were in other locations of the pancreas. This may have been due to the difficulty of accessing the lesions with EUS or the complicated vasculature around the splenic hilum, possibly resulting in incomplete EUS-ELTI. There are many important structures around the head of the pancreas, including the portal vein and superior mesenteric vessels, and injuring these vessels during the EUS-ELTI procedure can lead to severe adverse events. Massive portal vein thrombosis developed after EUS-ELTI in one patient whose lesion was located in the pancreatic head, near the portal vein. This study focused mainly on comparing the lesions in the body and tail of the pancreas; it obtained meaningful results since minimally invasive pancreatic resection of the pancreatic head lesion has not yet been accepted as a standard procedure. A comparative study of the lesions on the head of the pancreas will be conducted in the future.
Among the pathologic outcomes of 23 patients, two patients were diagnosed with cancer (8.7%). Among these two patients, one patient underwent EUS-ELTI to treat a neuroendocrine tumor, but the final pathology was hepatoid carcinoma. The other patient underwent EUS-ELTI to treat IPMN, but the final pathology was pancreatic ductal adenocarcinoma arising from IPMN with lymph node metastasis (One lymph node was reported as a metastatic lymph node among 11 harvested lymph nodes). Before performing EUS-ELTI, the initial diagnosis was always based on radiologic images. However, the initial diagnosis with radiologic images is not always precise, and an increased risk of oncologic safety can occur when the lesion includes malignancies like in this study.
Thus, an EUS guided chemo-ablation procedure should be considered very cautiously because of its suboptimal clinical data, often inaccurate of diagnosis, and compromised surgical outcomes. Although the present study has some limitations, including a small participant number, this study is significant because it is the first report presenting the surgical results after EUS-ELTI for physicians dealing with the endoscopic treatment of pancreatic cystic neoplasms.
In conclusion, surgical outcomes can be compromised or suboptimal after EUS-ELTI in pancreatic cystic tumors. Further investigations are needed for the efficacy and safety of the EUS-ELTI in the era of minimally invasive surgery.