Yoo Min Kim

Robotic versus Laparoscopic versus Open Gastrectomy: A Meta-Analysis

Purpose To define the role of robotic gastrectomy for the treatment of gastric cancer, the present systematic review with meta-analysis was performed. Materials and Methods A comprehensive search up to July 2012 was conducted on PubMed, EMBASE, and the Cochrane Library. All eligible studies comparing robotic gastrectomy versus laparoscopic gastrectomy or open gastrectomy were included. Results Included in our meta-analysis were seven studies of 1,967 patients that compared robotic (n=404) with open (n=718) or laparoscopic (n=845) gastrectomy. In the complete analysis, a shorter hospital stay was noted with robotic gastrectomy than with open gastrectomy (weighted mean difference: -2.92, 95% confidence interval: -4.94 to -0.89, P=0.005). Additionally, there was a significant reduction in intraoperative blood loss with robotic gastrectomy compared with laparoscopic gastrectomy (weighted mean difference: -35.53, 95% confidence interval: -66.98 to -4.09, P=0.03). These advantages were at the price of a significantly prolonged operative time for both robotic gastrectomy versus laparoscopic gastrectomy (weighted mean difference: 63.70, 95% confidence interval: 44.22 to 83.17, P<0.00001) and robotic gastrectomy versus open gastrectomy (weighted mean difference: 95.83, 95% confidence interval: 54.48 to 137.18, P<0.00001). Analysis of the number of lymph nodes retrieved and overall complication rates revealed that these outcomes did not differ significantly between the groups. Conclusions Robotic gastrectomy for gastric cancer reduces intraoperative blood loss and the postoperative hospital length of stay compared with laparoscopic gastrectomy and open gastrectomy at a cost of a longer operating time. Robotic gastrectomy also provides an oncologically adequate lymphadenectomy. Additional high-quality prospective studies are recommended to better evaluate both short and long-term outcomes.

Clinical implication of an insufficient number of examined lymph nodes after curative resection for gastric cancer

The seventh edition of the tumor, lymph node (LN), metastasis (TNM) staging system increased the required number of examined LNs in gastric cancer from 15 to 16. However, the same staging system defines lymph node‐negative gastric cancer regardless of the number of examined LNs. In this study, the authors evaluated whether gastric cancer can be staged properly with fewer than 15 examined LNs.

Vitamin B12 deficiency after gastrectomy for gastric cancer: An analysis of clinical patterns and risk factors

Objective: To identify risk factors for postgastrectomy vitamin B12 deficiency and the time course of its development. Background: Postgastrectomy vitamin B12 deficiency worsens the quality of life of gastric cancer survivors, and vitamin B12–related neuropathy is irreversible if recognized late. However, the clinical pattern of vitamin B12 deficiency development after gastrectomy remains unclear. Methods: We reviewed 645 patients with gastric cancer who underwent distal subtotal gastrectomy (DG; n = 469) or total gastrectomy (TG, n = 176) between 2003 and 2010. Univariate and multivariate analyses were performed to identify risk factors for vitamin B12 deficiency and time to deficiency. Results: Cumulative vitamin B12 deficiency rates were 100% for TG and 15.7% for DG 4 years after surgery (P < 0.001). The median time to vitamin B12 deficiency was 15 months after TG, whereas the median time was not reached after DG. Preoperative vitamin B12 level was the only risk factor for vitamin B12 deficiency after TG, whereas both preoperative vitamin B12 level and age were risk factors after DG. There was positive linear correlation between preoperative vitamin B12 levels and the time to vitamin B12 deficiency after either TG (P < 0.001) or DG (P = 0.017). Conclusions: Vitamin B12 deficiency is an inevitable and rather early metabolic sequela after TG. Elderly patients with low preoperative vitamin B12 levels are more likely to experience vitamin B12 deficiency after DG. Thus, preoperative measurement and regular postoperative monitoring of vitamin B12 levels are necessary for early detection and treatment of postgastrectomy vitamin B12 deficiency.

Method of reconstruction governs iron metabolism after gastrectomy for patients with gastric cancer

Objective: Anemia after gastrectomy is commonly neglected by clinicians despite being an important and frequent long-term metabolic sequela. We hypothesized that the incidence and timing of the occurrence of iron deficiency after gastrectomy is closely associated with the extent of gastrectomy and the reconstruction method, and we investigated the treatment outcomes of iron supplementation to understand iron metabolism and determine the optimal reconstruction method after gastrectomy. Patients and Methods: Using a prospective gastric cancer database, we identified 381 patients with early gastric cancer with complete hematologic parameters who underwent gastrectomy between January 2004 and May 2008. Kaplan-Meier methods, Cox regression, and logistic regression were used to evaluate the associations of the extent of gastrectomy and reconstruction method with iron metabolism. Results: The prevalence of iron deficiency 3 years after gastrectomy was 69.1%, and iron-deficiency anemia was observed in 31.0% of patients. Iron deficiency developed in 64.8% and 90.5% of patients after distal gastrectomy and total gastrectomy within 3 years after surgery (P < 0.0001), respectively. Iron deficiency was significantly more frequent in women than in men (P < 0.0001) and after gastrojejunostomy than after gastroduodenostomy (P < 0.0001). Serum ferritin levels were different according to the extent of gastrectomy and reconstruction method. The proportion of patients treated for iron-deficiency anemia was also significantly different according to the extent of gastrectomy (P = 0.020). Conclusions: Iron deficiency occurs in most patients with gastric cancer after gastrectomy, and its incidence was different according to the extent of gastrectomy and reconstruction method. To improve iron metabolism after distal gastrectomy, gastroduodenostomy would be the method of reconstruction whenever possible.

Clinical application of image-enhanced minimally invasive robotic surgery for gastric cancer: a prospective observational study.

BackgroundThis study was performed to validate the feasibility and role of image-guided robotic surgery using preoperative computed tomography (CT) images for the treatment of gastric cancer.MethodsTwelve patients scheduled to undergo robotic gastrectomy for gastric cancer were registered. Vessels encountered during gastrectomy were reconstructed using 3D software and their anatomical variation was evaluated using preoperatively performed CT-angiography. The vascular information was transferred to a robot console using a multi-input display mode. Radiologic findings acquired from preoperative CT by the radiologist were compared with intraoperative findings of the surgeon. This study is registered with www.clinicaltrials.gov as NCT01338948.ResultsAll 12 robotic gastrectomies were performed without any problems. All anatomical data acquired using 3D software were transferred successfully during surgery. Intraoperative vascular images depicted vasculatures around the stomach and could identify important vascular variations. During surgery, relevant vascular information led the surgeon to branch sites and facilitated lymphadenectomy around the vessels. Image-guidance during the operation provided a vascular map and enabled the surgeon to avoid accidental bleeding and damage to other organs by preventing vascular injuries.ConclusionImage-guided robotic surgery for gastric cancer using preoperative CT-angiography reconstructed during operation by a surgically trained radiologist who could adjust the images by anticipating the operative procedure was feasible and improved the efficiency of surgery by eliminating the possibility of vascular injuries.

Fluorescent Iodized Emulsion for Pre- and Intraoperative Sentinel Lymph Node Imaging: Validation in a Preclinical Model

PURPOSE To validate the usefulness of a newly developed tracer for preoperative gastric sentinel lymph node (LN) (SLN) mapping and intraoperative navigation after a single preoperative submucosal injection in rat and beagle models. MATERIALS AND METHODS This study was approved by the Experimental Animal Ethical Committee of Yonsei University College of Medicine according to the eighth edition of the Guide for the Care and Use of Laboratory Animals published in 2011. An emulsion was developed that contained indocyanine green in iodized oil, which can be visualized with both computed tomography (CT) and near-infrared (NIR) optical imaging and has the property of delayed washout. This emulsion was injected into the footpad of rats (n = 6) and the gastric submucosa of beagles (n = 8). CT lymphography was performed. The degree of enhancement of popliteal LNs was measured in rats, and the enhancing LNs were identified and the degree of enhancement of the enhancing LNs was measured in beagles. Next, NIR imaging was performed in beagles during open, laparoscopic, and robotic surgery to identify LNs containing the fluorescent signals of indocyanine green. The enhanced LNs detected with CT lymphography and NIR imaging were matched to see if they corresponded. RESULTS Preoperative CT lymphography facilitated SLN mapping, and 26 SLNs were identified in eight beagles. NIR imaging enabled high-spatial-resolution visualization of both SLNs and the intervening lymphatic vessels and was useful for intraoperative SLN navigation. CONCLUSION SLN mapping with fluorescent iodized oil emulsion is effective and feasible for both CT and NIR imaging.

Image-based Approach for Surgical Resection of Gastric Submucosal Tumors

Purpose This study was done to evaluate the usefulness of preoperative computed tomography (CT) and intraoperative laparoscopic ultrasound to facilitate treatment of gastric submucosal tumors. Materials and Methods The feasibility of laparoscopic wedge resection as determined by CT findings of tumor size, location, and growth pattern was correlated with surgical findings in 89 consecutive operations. The role of laparoscopic ultrasound for tumor localization was analyzed. Results Twenty-three patients were considered unsuitable for laparoscopic wedge resection because of large tumor size (N=13) or involvement of the gastroesophageal junction (N=9) or pyloric channel (N=1). Laparoscopic wedge resection was not attempted in 11 of these patients because of large tumor size. Laparoscopic wedge resection was successfully performed in 65 of 66 (98.5%) patients considered suitable for this procedure. Incorrect interpretation of preoperative CT resulted in a change of surgery type in seven patients (7.9%): incorrect CT diagnosis on gastroesophageal junction involvement (N=6) and on growth pattern (N=1). In 18 patients without an exophytic growth pattern, laparoscopic ultrasound was necessary and successfully localized all lesions. Conclusions Preoperative CT and laparoscopic ultrasound are useful for surgical planning and tumor localization in laparoscopic wedge resection.

Beginner Surgeon's Initial Experience with Distal Subtotal Gastrectomy for Gastric Cancer Using a Minimally Invasive Approach.

Purpose Minimally invasive gastrectomy (MIG), including laparoscopic distal subtotal gastrectomy (LDG) and robotic distal subtotal gastrectomy (RDG), is performed for gastric cancer, and requires a learning period. However, there are few reports regarding MIG by a beginner surgeon trained in MIG for gastric cancer during surgical residency and fellowship. The aim of this study was to report our initial experience with MIG, LDG, and RDG by a trained beginner surgeon. Materials and Methods Between January 2014 and February 2015, a total of 36 patients (20 LDGs and 16 RDGs) underwent MIG by a beginner surgeon during the learning period, and 13 underwent open distal subtotal gastrectomy (ODG) by an experienced surgeon in Bundang CHA Medical Center. Demographic characteristics, operative findings, and short-term outcomes were evaluated for the groups. Results MIG was safely performed without open conversion in all patients and there was no mortality in either group. There was no significant difference between the groups in demographic factors except for body mass index. There were significant differences in extent of lymph node dissection (LND) (D2 LND: ODG 8.3% vs. MIG 55.6%, P=0.004) and mean operative time (ODG 178.8 minutes vs. MIG 254.7 minutes, P<0.001). The serial changes in postoperative hemoglobin level (P=0.464) and white blood cell count (P=0.644) did not show significant differences between the groups. There were no significant differences in morbidity. Conclusions This study showed that the operative and short-term outcomes of MIG for gastric cancer by a trained beginner surgeon were comparable with those of ODG performed by an experienced surgeon.

Totally laparoscopic Roux-en-Y gastrojejunostomy after laparoscopic distal gastrectomy: analysis of initial 50 consecutive cases of single surgeon in comparison with totally laparoscopic Billroth I reconstruction.

Purpose Roux-en-Y reconstruction (RY) in laparoscopic distal gastrectomy for gastric cancer is a more complicated procedure than Billroth-I (BI) or Billroth-II. Here, we offer a totally laparoscopic simple RY using linear staplers. Materials and Methods Each 50 consecutive patients with totally laparoscopic distal gastrectomy with RY and BI were enrolled in this study. Technical safety and surgical outcomes of RY were evaluated in comparison with BI. Results In all patients, RY gastrectomy using linear staplers was safely performed without any events during surgery. The mean operation time and anastomosis time were 177.0±37.6 min and 14.4±5.6 min for RY, respectively, which were significantly longer than those for BI (150.4±34.0 min and 5.9±2.2 min, respectively). There were no differences in amount of blood loss, time to flatus passage, diet start, length of hospital stay, and postoperative inflammatory response between the two groups. Although there was no significant difference in surgical complications between RY and BI (6.0% and 14.0%), the RY group showed no anastomosis site-related complications. Conclusion The double stapling method using linear staplers in totally laparoscopic RY reconstruction is a simple and safe procedure.

The clinical implications of FDG-PET/CT differ according to histology in advanced gastric cancer

BackgroundThe prognostic impact of preoperative 18F-FDG PET/CT in advanced gastric cancer (AGC) remains a matter of debate. This study aims to evaluate the prognostic impact of SUVmax in preoperative 18F-FDG PET/CT of AGC according to histologic subtype, with a focus on the differences between tubular adenocarcinoma and signet ring cell (SRC) carcinoma.MethodsAs a discovery set, a total of 727 AGC patients from prospective database were analyzed according to histologic subtype with Cox proportional hazard model and p-spline curves. In addition, another 173 patients from an independent institution was assessed as an external validation set.ResultsIn multivariate analysis, high SUVmax in preoperative 18F-FDG PET/CT of AGC was negatively correlated with disease-free survival (DFS) and overall survival (OS) in patients with diffuse type (DFS: HR 2.17, P < 0.001; OS: HR 2.47, P < 0.001) or SRC histology (DFS: HR 2.26, P = 0.005; OS: HR 2.61, P = 0.003). This negative prognostic impact was not observed in patients with intestinal type or well or moderately differentiated histology. These findings have been consistently confirmed in a validation set. The p-spline curves also showed a gradual increase in log HR as SUVmax rises only for SRC histology and for diffuse-type AGC. Finally, a novel predictive model for recurrence of AGC with diffuse type or SRC histology was generated and validated based on the preoperative SUVmax.ConclusionsPreoperative high SUVmax of AGC is a poor prognostic factor in those with diffuse type or SRC histology. This study is the first to demonstrate the differential prognostic impact of preoperative PET/CT SUVmax in AGC according to histologic subtype and provide a clue to explain previous discrepancies in the prognostic impact of preoperative PET/CT in AGC. Prospective studies are required to validate the role of preoperative SUVmax in AGC.