Feasibility of Non-Exposure Simple Suturing Endoscopic Full-Thickness Resection in Comparison with Laparoscopic Endoscopic Cooperative Surgery for Gastric Subepithelial Tumors: Results of Two Independent Prospective Trials.

Recently, nonexposure simple suturing endoscopic full-thickness resection (NESS-EFTR) method was developed to avoid tumor exposure to the peritoneal cavity. The aim of this study is to compare the short-term outcomes of the NESS-EFTR method with those of laparoscopic and endoscopic cooperative surgery (LECS) for gastric subepithelial tumors (SETs). A prospective single-center trial of LECS for gastric SETs was performed from March 2012 to October 2013 with a separate prospective trial of NESS-EFTR performed from August 2015 to June 2017, enrolling 15 patients each. Among the 30 enrolled patients, 14 who underwent LECS and 11 who underwent NESS-EFTR were finally included in the analysis. The rate of complete resection and successful closure was 100% in both groups. The operating time was longer for NESS-EFTR group than for LECS (110 vs. 189 min; p < 0.0001). There were no postoperative complications except one case of transient fever in the NESS-EFTR group. One patient in the LECS group had peritoneal seeding of gastrointestinal stromal tumor at 17 months postoperatively, and there was no other recurrence. Although NESS-EFTR had long operating and procedure times, it was feasible for patients with gastric SETs requiring a nonexposure technique.

Non-exposure Simple Suturing Endoscopic Full-thickness Resection with Sentinel Basin Dissection in Patients with Early Gastric Cancer: the SENORITA 3 Pilot Study.

PURPOSE: Recently, non-exposure simple suturing endoscopic full-thickness resection (NESS-EFTR) was developed to prevent tumor exposure to the peritoneal cavity. This study aimed to evaluate the feasibility of NESS-EFTR with sentinel basin dissection for early gastric cancer (EGC). MATERIALS AND METHODS: This was the prospective SENORITA 3 pilot. From July 2017 to January 2018, 20 patients with EGC smaller than 3 cm without an absolute indication for endoscopic submucosal dissection were enrolled. The sentinel basin was detected using Tc99m-phytate and indocyanine green, and the NESS-EFTR procedure was performed when all sentinel basin nodes were tumor-free on frozen pathologic examination. We evaluated the complete resection and intraoperative perforation rates as well as the incidence of postoperative complications. RESULTS: Among the 20 enrolled patients, one dropped out due to large tumor size, while another underwent conventional laparoscopic gastrectomy due to metastatic sentinel lymph nodes. All NESS-EFTR procedures were performed in 17 of the 18 other patients (94.4%) without conversion, and the complete resection rate was 83.3% (15/18). The intraoperative perforation rate was 27.8% (5/18), and endoscopic clipping or laparoscopic suturing or stapling was performed at the perforation site. There was one case of postoperative complications treated with endoscopic clipping; the others were discharged without any event. CONCLUSIONS: NESS-EFTR with sentinel basin dissection is a technically challenging procedure that obtains safe margins, prevents intraoperative perforation, and may be a treatment option for EGC after additional experience. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03216174.

Current status and challenges in sentinel node navigation surgery for early gastric cancer.

Although a number of feasibility studies for sentinel node (SN) concepts in gastric cancer have been conducted since 2000, there remains a debate regarding detailed detection techniques and oncological safety. Two important multicenter phase II clinical trials were performed in Japan that used different methods and reached different conclusions; one confirmed acceptable results with a false-negative rate of 7%, and the other showed an unacceptably high false-negative rate of 46.4%. The Sentinel Node Oriented Tailored Approach (SENORITA) trial is a multicenter randomized controlled phase III trial being performed in Korea. Patient enrollment is now complete and the long-term results are currently awaited. Recently, an image-guided SN mapping technique using infrared ray/fluorescence was introduced. This method might be a promising technology because it allows the clear visualization of SNs. With regard to the primary tumor, the non-exposed endoscopic wall-inversion surgery technique and non-exposure endolaparoscopic full-thickness resection with simple suturing technique have been reported. These methods prevent abdominal infection and tumor seeding and can be good alternatives to conventional laparoscopic gastric wedge resection. For indications, SN navigation surgery can be extended to patients who underwent non-curative endoscopic resection. Although a few studies have been performed on these patients, sentinel concepts may be beneficial to patients as they omit the need for additional gastrectomy. SN navigation surgery can lead to actual organ-preserving surgery and plays a key role in improving the quality of life of patients with early gastric cancer in the future.

Practical intraoperative pathologic evaluation of sentinel lymph nodes during sentinel node navigation surgery in gastric cancer patients - Proposal of the pathologic protocol for the upcoming SENORITA trial.

Over the last decade, as the number of patients with early gastric cancer increased and the subsequent survival rate improved, there has been a consistent effort to verify the applicability of the sentinel node concept in gastric cancer in a bid to improve postoperative quality of life in these patients. During sentinel node navigation surgery in gastric cancer patients, intraoperative pathologic examination of the retrieved sentinel nodes plays a critical role in determining the extent of surgery, but the optimal method is still under debate. Currently, a multicenter, phase III clinical trial is underway to compare laparoscopic sentinel basin dissection with stomach preserving surgery and standard laparoscopic gastrectomy in terms of oncologic outcomes in patients with clinical stage T1N0 gastric cancer. Herein, the currently available intraoperative pathologic techniques are reviewed and their clinical significance and applicability are appraised based on the published literature. The proper pathologic examination of the sentinel lymph nodes in an upcoming clinical trial (SENORITA trial) is also proposed here based on this review.

Robot-assisted gastrectomy for early gastric cancer: is it beneficial in viscerally obese patients compared to laparoscopic gastrectomy?

BACKGROUND: The adoption of robotic systems for gastric cancer surgery has been proven feasible and safe; however, a benefit over the laparoscopic approach has not yet been well-documented. We aimed to investigate the surgical outcomes of robotic versus laparoscopic gastrectomy for gastric cancer, according to the extent of surgery and patients' obesity status. METHODS: Between January 2009 and July 2011, 770 patients were enrolled in this retrospective analysis. All had stage IA/IB gastric cancer preoperatively and underwent either laparoscopic (n = 622) or robotic (n = 148) gastrectomy. Patients were classified into obese and non-obese groups on the basis of visceral fat area (VFA). The extent of surgery was defined by whether patients underwent distal or total gastrectomy. RESULTS: The surgical outcomes following distal gastrectomy were similar between the robotic and laparoscopic groups regardless of the obesity status. After total gastrectomy, the number of total and N2-area lymph nodes were significantly higher in the robotic group than in the laparoscopic group in non-obese patients with VFA < 100 cm(2) (total, 38.8 vs. 46.5; p = 0.018; N2 area, 9.0 vs. 12.4; p = 0.041), but no significant differences were observed in obese population. Robotic group developed less severe complications after total gastrectomy compared to laparoscopic group in non-obese patients (p = 0.036). CONCLUSION: Robotic assistance did not improve surgical outcomes over the laparoscopic approach in obese patients undergoing distal gastrectomy. However, non-obese patients with low VFA may benefit from robotic assistance during total gastrectomy in terms of radical D2 lymphadenectomy with fewer serious complications.

Robot-assisted total gastrectomy is comparable with laparoscopically assisted total gastrectomy for early gastric cancer.

BACKGROUND: Laparoscopically assisted total gastrectomy (LATG) is technically difficult. Robot surgery has theoretical advantages such as increased degrees of freedom of instruments and a three-dimensional view. The current study aimed to determine whether a robot-assisted total gastrectomy (RATG) has a real benefit over LATG in terms of surgical and oncologic outcomes. METHODS: A single-center case-control study was conducted. The study included 36 patients who underwent RATG and 65 patients who underwent LATG at the National Cancer Center in Korea between February 2009 and May 2011. No patients were excluded from the analysis within the study period. Clinicopathologic data, operative data, postoperative morbidity, and pathologic data were analyzed by Student's t-tests and Chi-square tests, as indicated. RESULTS: The mean age of the patients was 53.9 ± 11.7 years in the RATG group and 56.9 ± 12.3 years in the LATG group (P = 0.236). The mean BMI was 23.2 ± 2.5 kg/m(2) in the RATG group and 23.6 ± 3.4 kg/m(2) in the LATG group (P = 0.494). The mean postoperative hospital stay was 8.8 ± 3.3 days in the RATG group and 10.3 ± 10.8 days in the LATG group (P = 0.416). The mean operative time was 305.8 ± 115.8 min in the RATG group and 210.2 ± 57.7 min in the LATG group (P < 0.001). The mean number of dissected lymph nodes was 42.8 ± 12.7 in the RATG group and 39.4 ± 13.4 in the LATG group (P = 0.209). Postoperative complications were experienced by 6 patients (16.7%) in the RATG group and 10 patients (15.4%) in the LATG group (P = 0.866). CONCLUSION: Despite early experiences, RATG was shown to be comparable with LATG in terms of surgical and oncologic outcomes. However, no apparent benefit is associated with RATG to date.

Effects of ATP and LTC4 on hypoxic pulmonary vasoconstriction in isolated rat lungs.

BACKGROUND: Hypoxic pulmonary vasoconstriction (HPV) is unique to pulmonary circulation but the mechanism remains elusive. Red blood cells (RBCs) are known to augment HPV and to release more ATP as oxygen content falls. Leukotrienes constrict smooth muscle and could be important for the regulation of the pulmonary circulation. Hence we hypothesized that ATP and leukotrienes are mediators of HPV produced during acute alveolar hypoxia. METHODS: In forty Sprague-Dawley rats, lungs were isolated and perfused. We administered ATP (10 micrometer) to the ATP group (n = 8), the ATP antagonist, suramin (100 micrometer) to the suramin group (n = 8), leukotriene C4 (LTC4, 5 microgram) to the LTC4 group (n = 8), the LTC4 antagonist, LY171883 (20 micrometer) to the LY171883 group (n = 8), and LTC4 (5 microgram) + ATP (10 micrometer) to the LTC4 + ATP group (n = 8) during normoxic ventilation. HPV responses were induced by three hypoxic challenges for 5 minutes separated by 5 minutes of ventilation with a normoxic gas mixture. Baseline pulmonary artery pressure change after exposure to each drug and hypoxic pressor response between a period 21% normoxic gas ventilation and that of 3% hypoxic gas ventilation were measured. RESULTS: ATP and LTC4 + ATP increased baseline pulmonary artery pressures but LTC4 did not alter it. ATP did not affect hypoxic pressor response. Suramin, LY171883 and LTC4 + ATP inhibited the pressor response to hypoxia. LTC4 increased hypoxic pressor response. CONCLUSIONS: In isolated rat lungs, HPV may be mediated by ATP and LTC4 appears more likely to be a modulator than a mediator of HPV.