Early phase II study of robot-assisted distal gastrectomy with nodal dissection for clinical stage IA gastric cancer

The artificial intelligence revolution in gastric cancer management: clinical applications

Nowadays, gastric cancer has become a significant issue in the global cancer burden, and its impact cannot be ignored. The rapid development of artificial intelligence technology is attempting to address this situation, aiming to change the clinical management landscape of gastric cancer fundamentally. In this transformative change, machine learning and deep learning, as two core technologies, play a pivotal role, bringing unprecedented innovations and breakthroughs in the diagnosis, treatment, and prognosis evaluation of gastric cancer. This article comprehensively reviews the latest research status and application of artificial intelligence algorithms in gastric cancer, covering multiple dimensions such as image recognition, pathological analysis, personalized treatment, and prognosis risk assessment. These applications not only significantly improve the sensitivity of gastric cancer risk monitoring, the accuracy of diagnosis, and the precision of survival prognosis but also provide robust data support and a scientific basis for clinical decision-making. The integration of artificial intelligence, from optimizing the diagnosis process and enhancing diagnostic efficiency to promoting the practice of precision medicine, demonstrates its promising prospects for reshaping the treatment model of gastric cancer. Although most of the current AI-based models have not been widely used in clinical practice, with the continuous deepening and expansion of precision medicine, we have reason to believe that a new era of AI-driven gastric cancer care is approaching.

Identification of Biomarkers for Assessing Treatment Efficacy of Chemotherapy plus Nivolumab as the First Line in Patients with Unresectable Advanced or Recurrent Gastric Cancer: A Multicenter Study

INTRODUCTION

In this study, we aimed to identify biomarkers for predicting treatment outcomes and efficacy of chemotherapy plus nivolumab, as well as predict immune-related adverse events (irAEs) characteristics of immune checkpoint inhibitors.

METHODS

This multicenter study included 104 patients who received chemotherapy plus nivolumab as the primary treatment for unresectable advanced recurrent gastric cancer. Blood test results were collected before the start and after two courses of treatment. The neutrophil-lymphocyte ratio, prognostic nutritional index, and lactate dehydrogenase/albumin ratio (LAR) were examined after treatment in each case to determine changes compared to values before the start of treatment.

RESULTS

A total of 57 (54.8%) patients experienced a complete or partial response. The LAR of the stable disease/progressive disease group significantly increased (p = 0.018). An examination of the presence of grade ≥3 irAEs and changes in related factors showed that the LAR of all patients increased.

CONCLUSION

The LAR was correlated with the best therapeutic response; therefore, it may be a potential biomarker of treatment outcomes and efficacy.

Application of artificial intelligence for improving early detection and prediction of therapeutic outcomes for gastric cancer in the era of precision oncology

Gastric cancer is a leading contributor to cancer incidence and mortality globally. Recently, artificial intelligence approaches, particularly machine learning and deep learning, are rapidly reshaping the full spectrum of clinical management for gastric cancer. Machine learning is formed from computers running repeated iterative models for progressively improving performance on a particular task. Deep learning is a subtype of machine learning on the basis of multilayered neural networks inspired by the human brain. This review summarizes the application of artificial intelligence algorithms to multi-dimensional data including clinical and follow-up information, conventional images (endoscope, histopathology, and computed tomography (CT)), molecular biomarkers, etc. to improve the risk surveillance of gastric cancer with established risk factors; the accuracy of diagnosis, and survival prediction among established gastric cancer patients; and the prediction of treatment outcomes for assisting clinical decision making. Therefore, artificial intelligence makes a profound impact on almost all aspects of gastric cancer from improving diagnosis to precision medicine. Despite this, most established artificial intelligence-based models are in a research-based format and often have limited value in real-world clinical practice. With the increasing adoption of artificial intelligence in clinical use, we anticipate the arrival of artificial intelligence-powered gastric cancer care.

Advantages of a robotic approach compared with laparoscopy gastrectomy for patients with high visceral fat area

BACKGROUND

Gastric cancer surgery for obese patients is regarded as a technically challenging procedure. The morbidity after gastrectomy has been reported to be significantly higher in patients with high visceral fat area (VFA). Robotic gastrectomy (RG) is expected to be advantageous for complicated operations. However, whether RG is superior to conventional laparoscopic gastrectomy (LG) for patients with visceral fat obesity remains unclear. The present study aimed to clarify the impact of RG on the short- and long-term outcomes of patients with high VFAs.

METHODS

This study included 1306 patients with clinical stage I/II gastric cancer who underwent minimally invasive gastrectomy between January 2012 and December 2020. The patients were subclassified according to VFA. The short- and long-term outcomes of RG were compared with those of LG in two VFA categories.

RESULTS

This study included 394 (high-VFA, 151; low-VFA, 243) and 882 patients (high-VFA, 366; low-VFA, 516) in the RG and LG groups, respectively. RG was associated with a significantly longer operative time than LG (high-VFA, P < 0.001; low-VFA, P < 0.001). The incidence rates of overall and intra-abdominal infectious complications in the high-VFA patients were lower in the RG group than in the LG group (P = 0.019 and P = 0.048, respectively) but not significantly different from those in the low-VFA patients. In the multivariate analysis, LG was identified as the only independent risk factor of overall (odds ratio [OR] 3.281; P = 0.012) and intra-abdominal infectious complications (OR 3.462; P = 0.021) in the high-VFA patients. The overall survival of high-VFA patients was significantly better in the RG group than in the LG group (P = 0.045).

CONCLUSIONS

For patients with visceral fat obesity, RG appears to be advantageous to LG in terms of reducing the risk of complications and better long-term survival.

Comparisons of surgical outcomes between robotic and laparoscopic total gastrectomy in patients with clinical stage I/IIA gastric cancer

BACKGROUND

The robotic approach is especially promising for challenging surgeries, such as total gastrectomy. However, it remains unclear whether robotic total gastrectomy (RTG) is superior to conventional laparoscopic total gastrectomy (LTG). The present study aimed to clarify the impact of RTG on short- and long-term outcomes for patients with clinical stage I/IIA gastric cancer.

METHODS

This study included 98 patients with clinical stage I/IIA gastric cancer who underwent minimally invasive total gastrectomy from October 2013 to December 2020 at the Shizuoka Cancer Center. The short- and long-term outcomes of RTG were compared with those of LTG.

RESULTS

This study included 36 RTG and 58 LTG patients. RTG was associated with a significantly longer operative time than LTG (p = 0.023). All complications tended to be lower in the RTG group than in the LTG group (2.8% and 15.5%, respectively; p = 0.083). There were no patients with anastomotic leakage in the RTG group. The multivariate analysis identified LTG as the only independent risk factor for postoperative complications (odds ratio, 6.620; 95% confidence interval, 1.132-126.4; p = 0.034). The survival of the RTG and LTG groups was equivalent.

CONCLUSIONS

RTG reduced the risk of complications compared to LTG. Patients treated using the two approaches showed equivalent survival.

Current Status and Trends of Minimally Invasive Gastrectomy in Korea

Since its introduction in the early 1990s, laparoscopic gastrectomy has been widely accepted for the treatment of gastric cancer worldwide. In the last decade, the Korean Laparoendoscopic Gastrointestinal Surgery Study group performed important clinical trials and exerted various efforts to enhance the quality of scientific knowledge and surgical techniques in the field of gastric cancer surgery. Laparoscopic gastrectomy has shifted to a new era in Korea due to recent advances and innovations in technology. Here, we discuss the recent updates of laparoscopic gastrectomy—namely, reduced-port, single-incision, robotic, image-guided, and oncometabolic surgery.

Hybrid Robotic and Laparoscopic Gastrectomy for Gastric Cancer: Comparison with Conventional Laparoscopic Gastrectomy

Purpose

The benefits of robotic gastrectomy remain controversial. We designed this study to elucidate the advantages of a hybrid robot and laparoscopic gastrectomy over conventional laparoscopic surgery.

Materials and Methods

A total of 176 patients who underwent gastrectomy for gastric cancer were included in this study. We compared 88 patients treated with hybrid robotic and laparoscopic gastrectomy (HRLG) and 88 patients who underwent conventional laparoscopic gastrectomy (CLG). In HRLG, suprapancreatic lymph node (LN) dissection was performed in a robotic setting. Clinicopathological characteristics, operative details, and short-term outcomes were analyzed for the patients.

Results

The number of LNs retrieved from the suprapancreatic area was significantly greater in the HRLG group (11.27±5.46 vs. 9.17±5.19, P=0.010). C-reactive protein levels were greater in the CLG group on both postoperative day (POD) 1 (5.11±2.64 vs. 4.29±2.38, P=0.030) and POD 5 (9.86±6.51 vs. 7.75±5.17, P=0.019). In addition, the neutrophil-to-lymphocyte ratio was significantly greater in the CLG group on both POD 1 (7.44±4.72 vs. 6.16±2.91, P=0.031) and POD 5 (4.87±3.75 vs. 3.81±1.87, P=0.020). Pulmonary complications occurred only in the CLG group (4/88 [4.5%] vs. 0/88 [0%], P=0.043).

Conclusions

HRLG is superior to CLG in terms of suprapancreatic LN dissection and postoperative inflammatory response.

Application of robots in general surgery

Background: Application of robotic surgery in the field of general surgery has been increasing. This paper is an overview of the current uses and future perspectives of robotic surgery in four major divisions—endocrine, upper gastrointestinal, hepato-biliary-pancreatic (HBP), and colorectal surgery.Current Concepts: In endocrine surgery, cosmetic advantage is the highest priority when selecting a surgical approach for thyroidectomy. Currently, the transaxillary route is the most common approach. The introduction of the single-port system could maximize the advantages of this technique. In upper gastrointestinal surgery, the use of robots has the advantage of better retrieval of lymph nodes, less bleeding, earlier discharge, and less complications than the laparoscopic approach. However, a more prospective comparative trial is required to confirm those findings. In the HBP field, the indications of robotic surgery have expanded, starting with cholecystectomy to more challenging procedures, such as donor hepatectomy and pancreaticoduodenectomy. Meticulous dissection using robots could provide benefits to patients. In colorectal surgery, robotic surgery is an excellent technical tool for minimally invasive surgeries for rectal cancers, especially in male patients with narrow, deep pelvises. However, further studies are required to confirm the impact of robotic surgery on rectal cancers.Discussion and Conclusion: Robots are used to provide optimal surgical outcomes. Investigating new technologies and innovative surgical procedures is the highly important for a surgeon in the era of minimally invasive surgery.

The 140 years' journey of gastric cancer surgery: From the two hands of Billroth to the multiple hands of the robot

After the initial achievement by Billroth in 1881, surgery for gastric cancer has become increasingly extended. However, it turned out to be limited in Western countries after the publication that denied the role of extended surgery in the 1960s. While surgeons in Japan were still enthusiastic about extended surgery, the Japan Clinical Oncology Group (JCOG) conducted clinical trials to validate the role of extended surgery. Contrary to expectations, the efficacy of extended surgery was not demonstrated. In gastric cancer surgery, postoperative complications were reported to be associated with poor survival. A survival benefit could not be obtained by extended surgery, with high morbidity. Therefore, the paradigm had been changed from extended surgery to minimally invasive surgery (MIS). As an MIS for gastric cancer, laparoscopic surgery has been considered a practical method. Initial laparoscopic gastrectomy (LG) was first performed by Kitano in 1991. Thereafter, LG became increasingly common. Several clinical trials demonstrated the noninferiority of LG to open gastrectomy. LG is now regarded as the standard for cStage I gastric cancer, and the indication is expanding to advanced cancer. However, LG has some drawbacks owing to the restriction of movement caused by straight-shaped forceps. Robotic gastrectomy (RG) is considered a major breakthrough to circumvent the drawbacks in LG using articulated devices. However, the solid evidence demonstrating the advantage of RG has not been proved yet. The JCOG is now conducting a randomized controlled trial to evaluate the superiority of RG to LG in terms of reducing morbidity.

Clinical outcomes and functional analysis of third space robotic and endoscopic cooperative surgery versus laparoscopic wedge resection for gastric submucosal tumours: a propensity score-matched study

Third space robotic and endoscopic cooperative surgery (TS-RECS) is a novel minimally invasive surgery for resecting gastric submucosal tumours (GSMTs), which could accomplish the completely oncological curability and maximal functional preservation. This study investigated the clinical outcomes and gastrointestinal function after TS-RECS versus laparoscopic wedge resection (LWR) for GSMTs. This was a single-centre retrospective study that included 130 patients with GSMTs who underwent LWR or TS-RECS from 2013 to 2019. To overcome selection biases, we performed propensity score matching (1:1) using seven covariates that could impact the group assignment and outcomes. Then, the clinical outcomes and gastrointestinal function in the LWR and TS-RECS groups were compared in a matched cohort. Among the 130 enrolled patients, 96 patients underwent LWR, and 34 underwent TS-RECS and were matched into 30 patients for each group. There was no significant difference in the operation time between the two groups (P = 0.543). However, the TS-RECS group had significantly less blood loss (20,5–100 vs 95,10–310 ml, P < 0.0001) and better postoperative recovery in terms of time to oral intake (2,2–4 vs 3,2–6 days, P < 0.0001) and postoperative hospital stay (5,4–10 vs 8.5,5–16 days, P < 0.0001) than the LWR group. The severity and frequency scores of postoperative gastrointestinal symptoms in the TS-RECS group were significantly lower than those in the LWR group. The median follow-up period was 24 months (10–60 months) in the LWR group and 18 months (10–27 months) in the TS-RECS group, and there was in total a single recurrence in the LWR group. TS-RECS appears to be a technically safe and effective surgery with preservation of gastrointestinal function for resection of GSMT resection.

Robotic Gastrectomy Compared with Laparoscopic Gastrectomy for Clinical Stage I/II Gastric Cancer Patients: A Propensity Score-Matched Analysis

BACKGROUND

Robotic gastrectomy (RG) has been developed to address the drawbacks of laparoscopic gastrectomy (LG); however, whether or not RG is superior to conventional LG remains to be seen. The present study aimed to clarify the impact of RG on clinical stage I/II gastric cancer patients.

METHODS

The present study included 1208 patients with clinical stage I/II gastric cancer who had minimally invasive gastrectomy from January 2012 to March 2020 at the Shizuoka Cancer Center. The short- and long-term outcomes of RG and LG were compared after propensity score matching.

RESULTS

This study involved 835 LG and 345 RG patients. After propensity score matching, there were 342 patients each in the RG and LG groups, with an improved balance of confounding factors between the two groups. RG was associated with a significantly longer operative time and lower amylase concentration in the drainage fluid on the first postoperative day than LG. Furthermore, the incidence of intra-abdominal infectious complications in the RG was lower than that in the LG (4.4% vs. 9.4%; P = 0.015). The survival of the RG and LG groups was equivalent.

CONCLUSIONS

RG reduced the risk of intra-abdominal infectious complications in comparison with LG in the propensity score-matched analysis. Patients treated by the two approaches showed equivalent survival.

Pooled analysis of the oncological outcomes in robotic gastrectomy versus laparoscopic gastrectomy for gastric cancer

Aim:

Robotic gastrectomy (RG) is more and more widely used in the treatment of gastric cancer. However, the long-term oncological outcomes of RG have not been well evaluated. The aim of this study was to evaluate the long-term oncological outcomes of RG and laparoscopic gastrectomy (LG) in the treatment of gastric cancer.

Materials and Methods:

PubMed, China National Knowledge Infrastructure, Cochrane Library and EMBASE electronic databases were searched until August 2019. Eligible studies were analysed for comparison of oncological outcomes between RG and LG in patients with gastric cancer.

Results:

Eleven retrospective comparative studies, which included 1347 (32.52%) patients in the RG group and 2795 (67.48%) patients in the LG group, were selected for the analysis. Meta-analysis of the 11 included studies showed that there was no statistically significant difference in the OS between the RG and LG groups (hazard ratios [HRs] = 0.97, 95% confidence intervals [CIs] = 0.80–1.19, P = 0.80). Six studies evaluated disease-free survival (DFS), and pooled analysis showed that there was no statistically significant difference in DFS between RG group and LG group (HR = 0.94, 95% CIs = 0.72–1.23, P = 0.65). According to the odds ratio (OR) analysis, there was no significant difference in 3-year OS, 5-year OS, 3-year DFS and 5-year DFS between the RG and LG groups. Nine articles reported the recurrence rate, and the meta-analysis showed that there was no statistically significant difference between the RG and LG groups (OR = 0.88, 95% CIs = 0.69–1.12, P = 0.31).

Conclusions:

This meta-analysis indicated that the long-term oncological outcomes in the RG group were similar to that in the LG group.

Does three-dimensional surgery affect recurrence patterns in patients with gastric cancer after laparoscopic R0 gastrectomy? Results from a 3-year follow-up phase III trial

BACKGROUND

Numerous studies have shown that the short-term efficacy of three-dimensional (3D) laparoscopic radical gastrectomy (LG) is comparable to that of two-dimensional (2D)-LG. Whether 3D-LG affects the recurrence patterns of gastric cancer (GC) patients has not been investigated.

METHODS

From January 2015 to April 2016, a total of 419 patients were recruited for a phase III clinical trial (NCT02327481), which compared the short-term outcomes between the 2D and 3D groups. The long-term efficacy including recurrence patterns was compared between the 2D and 3D groups in this retrospective study. Multivariate analyses were performed to determine whether 3D-LG affects the recurrence patterns.

RESULTS

Ultimately, 401 patients were analyzed (197 in the 2D-LG group and 204 in the 3D-LG group), and no differences were observed in the clinicopathological data between the two groups. There were no significant differences between the two groups in the recurrence types, first recurrence time or recurrence-free survival (RFS) (all p > 0.05). According to the 7th American Joint Committee on Cancer tumor-node-metastasis (TNM) staging system, both groups were stratified into pathological stages I, II, and III. The stratified analysis showed no significant differences in RFS or overall survival (OS) among patients in each subgroup (all p > 0.05). The multivariate analysis of RFS showed that tumor diameter, pTNM stage, lymphovascular invasion, and adjuvant chemotherapy were independent factors (all p < 0.05). The multivariate analysis of post-recurrence survival (PRS) showed that adjuvant chemotherapy was an independent protective factor (p = 0.043).

CONCLUSIONS

3D-LG for GC did not differ significantly from 2D-LG in the effects on 3-year recurrence patterns, RFS and OS, which provides more tumor-related evidence for 3D technology. And due to the technological similarity, it may have certain reference value for robotic-assisted gastrectomy. Further multicenter, large-scale clinical trials are warranted.

Long-term outcomes of robotic gastrectomy for clinical stage I gastric cancer: a single-center prospective phase II study

INTRODUCTION

The outcomes of robotic gastrectomy (RG) for gastric cancer remain unclear due to a lack of prospective studies. We had previously designed and conducted a prospective phase II study of RG that showed favorable short-term outcomes. Herein, we aimed to determine the long-term outcomes of RG for clinical stage I gastric cancer.

PATIENTS AND METHODS

This single-center, prospective phase II study enrolled patients with clinical stage I gastric cancer undergoing RG. The survival outcomes, which were the secondary endpoints of the study, were evaluated.

RESULTS

Between December 2012 and April 2015, 120 patients were enrolled in this study. The 5-year overall survival (OS) was 96.7% (95% confidence interval [CI] 91.5-98.7%). The 5-year recurrence-free (RFS) and disease-specific survival (DSS) rates were 96.7% (95% CI 91.5-98.7%) and 99.2% (95% CI 94.3-99.9%), respectively. When confining the analysis to distal and pylorus-preserving gastrectomy, the 5-year OS, RFS, and DSS were 98.1% (95% CI 92.7-99.5%), 98.1% (95% CI 92.7-99.5%), and 100%, respectively. Only one patient died due to relapse of gastric cancer, while three died from other causes.

CONCLUSIONS

Long-term outcomes of RG was comparable to those of open and laparoscopic gastrectomy when the surgeries were performed by experienced surgeons in a high-volume center.

Obesity is a risk factor for internal hernia after laparoscopic or robot-assisted gastrectomy with mesenteric defect closure for gastric cancer

BACKGROUND

Internal hernia (IH) is a life-threatening complication after gastrectomy. The increase in the frequency of minimally invasive surgery is considered to be related to the increase in the frequency of IH, and mesenteric defect closure has been recommended to reduce this complication. However, IH can occur even when mesenteric defects are closed, so the risk of IH in the patients with mesenteric closure remains uncertain. We attempted to clarify the risk factors for IH in these patients.

METHODS

From 2013 to 2017, we retrospectively reviewed 310 patients with gastric cancer who underwent laparoscopic or robot-assisted gastrectomy with Roux-en-Y (RY) or double-tract (DT) reconstruction with mesenteric defect closure. Univariate and multivariate analyses were performed to identify the risk factors.

RESULTS

The incidence of IH was 1.3% (n = 4). A preoperative body mass index (BMI) ≥ 25 kg/m² (p = 0.044), postoperative chemotherapy (p = 0.034), and body weight loss rate at 6 months ≥ 15% (p = 0.045) were risk factors for IH on a univariate analysis. A multivariate analysis showed that a BMI at the time of surgery of ≥ 25 kg/m² was an independent risk factor for IH (odds ratio = 11.9, p = 0.049).

CONCLUSIONS

Preoperative obesity is an independent risk factor for IH after minimally invasive gastrectomy followed by RY or DT reconstruction with mesenteric defect closure. We need to conduct vigilant follow-up for IH, especially in these patients.

Robotic radical lymphadenectomy without touching the pancreas during gastrectomy for gastric cancer

Laparoscopic lymph node dissection around the peripancreatic area for gastric cancer (GC) remains challenging because of drawbacks in laparoscopic surgery including the limited range of movement, amplification of hand tremors, and inconvenient surgical positioning. In some cases of laparoscopic gastrectomy (LG), therefore, postoperative pancreatic fistula (POPF) occurs. Robotic surgery, on the other hand, plays an essential role in ergonomics and offers advantages, such as motion scaling, less fatigue, tremor filtering, 7 degrees of motion in the robotic instruments assisted by the wrist-like instruments tips, and three-dimensional vision. Robotic gastrectomy (RG) may enable surgeons to overcome the drawbacks associated with laparoscopic surgery. This study compares the safety and feasibility of short-term surgical outcomes of RG and LG for patients with GC.This was a single-center retrospective study of 659 consecutive patients with GC who received minimally invasive surgery. LG (n = 639) was performed between 2013 and 2017 and RG (n = 20) was performed in 2017. Lymphadenectomy without touching the pancreas was basically performed during RG using assisting articulating forceps.Overall incidence of postoperative complications higher than Clavien-Dindo grade 2 was not significantly different (LG group 5.9%, RG group 5.0%). In RG group, POPF, intra-abdominal abscess, and anastomotic leakage were not found, but postoperative bleeding requiring interventional catheter embolization occurred in 1 patient. In LG, POPF was found in 4.7%. Amylase levels in drainage fluid on postoperative day 1 were significantly lower in the RG group (238.5 IU/L) than in the LG group (884.5 IU/L) (P = .028).Regarding short-term surgical outcomes, RG is feasible, safe, and ideal treatment procedure for GC. Our robotic procedure without touching the pancreas may be associated with decreased incidence of POPF.

Comparison of Surgical Outcomes Between Robotic and Laparoscopic Distal Gastrectomy for cT1 Gastric Cancer

BACKGROUND

Increasing numbers of patients are treated by robotic distal gastrectomy (RDG); however, it remains unclear whether RDG is clinically comparable with conventional laparoscopic distal gastrectomy (LDG). This study aimed to clarify the feasibility of RDG from safety aspects.

METHODS

The study included 109 cT1 gastric cancer patients who underwent RDG at Shizuoka Cancer Center from January 2012 to April 2015. Short-term outcomes were compared with 160 cT1 gastric cancer patients who underwent LDG during the same period.

RESULTS

Patient characteristics were well matched. The RDG patients experienced longer operative times (323 min) than LDG patients (285 min; P < 0.001), although all other surgical outcomes were comparable between the groups. Drain amylase levels on POD 1 were significantly lower in the RDG group compared to LDG cases (median 452 U/L and 892 U/L; P < 0.001). The incidence of all complications was similar across the study patients, although intra-abdominal infectious complications tended to be lower in the RDG group than in the LDG group (2.8 and 8.1%; P = 0.112).

CONCLUSIONS

RDG was comparable to LDG in terms of feasibility for cT1 gastric cancer. RDG has the potential to reduce pancreas damage and thus to decrease intra-abdominal infectious complications.

Robotic oesophago-gastric cancer surgery

A postoperative complications rate of nearly 50% has compelled oesophago-gastric practice to adopt minimally invasive techniques such as robotic surgery

Long-term oncologic outcomes of robotic gastrectomy for gastric cancer compared with laparoscopic gastrectomy

BACKGROUND

Initial experiences with robotic gastrectomy (RG) for gastric cancer have demonstrated favorable short-term outcomes, suggesting that RG is an effective alternative to laparoscopic gastrectomy (LG). However, data on long-term survival and recurrence after RG for gastric cancer have yet to be reported. The objective of this study was to assess long-term outcomes after RG compared with LG.

METHODS

We retrospectively evaluated 313 and 524 patients who underwent RG or LG, respectively, for gastric cancer between July 2005 and December 2009. We compared long-term outcomes using the entire and a propensity-score matched cohort.

RESULTS

The entire cohort analysis revealed no statistically significant differences in 5-year overall survival(OS) or relapse-free survival(RFS) (p = 0.4112 and p = 0.8733, respectively): 93.3% [95% confidence interval (CI) 89.9-95.6] and 90.7% (95% CI, 86.9-93.5) after RG and 91.6% (95% CI 88.9-93.7) and 90.5% (95% CI 87.6-92.7) after LG, respectively; hazard ratios for death and recurrence in the robotic group were 0.828 (95% CI, 0.528-1.299; p = 0.4119) and 0.968 (95% CI, 0.649-1.445; p = 0.8741), respectively. The propensity-matched cohort analysis demonstrated no statistically significant differences for 5-year OS or RFS (p = 0.5207 and p = 0.2293, respectively): 93.2% and 90.7% after RG and 94.2% and 92.6% after LG, respectively; hazard ratios for death and recurrence in the robotic group were 1.194 (95% CI, 0.695-2.062; p = 0.5214) and 1.343 (95% CI, 0.830-2.192; p = 0.2321), respectively.

CONCLUSION

The potential technical superiority of robotic system over laparoscopy did not improve oncological outcomes after gastrectomy. Long-term oncological outcomes were not different between RG and LG. Nevertheless, robotic applications in minimally invasive gastric cancer surgery may be an oncologically safe alternative.

Impact of an Ultrasonically Activated Device in Robot-Assisted Distal Gastrectomy

Objective

Robot-assisted gastrectomy is increasingly used for the treatment of gastric cancer, although it remains a time-consuming procedure. An ultrasonically activated device might be useful to shorten operation times. This study therefore assessed the effect of ultrasonically activated device use on procedural times and on other early surgical outcomes.

Methods

Consecutive patients (N = 42) who underwent robot-assisted distal gastrectomy for gastric cancer were included. Clinicopathological characteristics and early surgical outcomes were compared between robotic-assisted gastrectomy procedures using an ultrasonically activated device (U group, n = 21) and those without it (NU group, n = 21).

Results

There were no significant differences in patient characteristics between the groups; however, the median operation time was significantly less in the U group than in the NU group (291 vs 351 minutes, P = 0.006). In detail, the median duration of console time until dividing the duodenum was less in the U group (70 vs 102 minutes, P < 0.001). Estimated blood loss, incidence of postoperative morbidity, and duration of postoperative hospital stay were not different between the groups.

Conclusions

An ultrasonically activated device reduced the operation time of robot-assisted gastrectomy without increasing blood loss and morbidity.

Robotic versus laparoscopic Gastrectomy for gastric cancer: a systematic review and updated meta-analysis

Background

Advanced minimally invasive techniques including robotic surgery are being employed with increasing frequency around the world, primarily in order to improve the surgical outcomes of laparoscopic gastrectomy (LG). We conducted a systematic review and meta-analysis to evaluate the feasibility, safety and efficacy of robotic gastrectomy (RG).

Methods

Studies, which compared surgical outcomes between LG and RG, were retrieved from medical databases before May 2017. Outcomes of interest were estimated as weighted mean difference (WMD) or risk ratio (RR) using the random-effects model. The software Review Manage version 5.1 was used for all calculations.

Results

Nineteen comparative studies with 5953 patients were included in this analysis. Compared with LG, RG was associated with longer operation time (WMD = −49.05 min; 95% CI: -58.18 ~ −39.91, P < 0.01), less intraoperative blood loss (WMD = 24.38 ml; 95% CI: 12.32 ~ 36.43, P < 0.01), earlier time to oral intake (WMD = 0.23 days; 95% CI: 0.13 ~ 0.34, P < 0.01), and a higher expense (WMD = −3944.8 USD; 95% CI: -4943.5 ~ −2946.2, P < 0.01). There was no significant difference between RG and LG regarding time to flatus, hospitalization, morbidity, mortality, harvested lymph nodes, and cancer recurrence.

Conclusions

RG can be performed as safely as LG. However, it will take more effort to decrease operation time and expense.

Robotic gastrectomy for gastric cancer

The number of robotic gastrectomy (RG) performed per year has been increasing, particularly in East Asia where the incidence of gastric cancer is high and approximately half of the cases are diagnosed as early gastric cancer. With articulated devices of RG, surgeons are able to perform every procedure more meticulously, which can result in less bleeding and damage to organs. There are many single arm and comparative studies, and these study showed similar trends, which included relatively less estimated blood loss and longer operation time following RG than laparoscopic gastrectomy (LG), equivalent number of harvested lymph nodes and similar length of postoperative hospital stay between RG and LG. Considering the results of these retrospective comparative studies, RG seems to be as feasible as LG in terms of early surgical outcomes. However, medical expense of RG is approximately twice as much as that of LG. Lack of solid evidence in terms of long-term outcomes is another problem. Considering the higher medical expenses associated with RG, its superiority in terms of long-term survival outcomes needs to be confirmed in the future for it to be accepted more widely.

Status and Prospects of Robotic Gastrectomy for Gastric Cancer: Our Experience and a Review of the Literature

Since the first report of robotic gastrectomy, experienced laparoscopic surgeons have used surgical robots to treat gastric cancer and resolve problems associated with laparoscopic gastrectomy. However, compared with laparoscopic gastrectomy, the superiority of robotic procedures has not been clearly proven. There are several advantages to using robotic surgery for gastric cancer, such as reduced estimated blood loss during the operation, a shorter learning curve, and a larger number of examined lymph nodes than conventional laparoscopic gastrectomy. The increased operation time observed with a robotic system is decreasing because surgeons have accumulated experience using this procedure. While there is limited evidence, long-term oncologic outcomes appear to be similar between robotic and laparoscopic gastrectomy. Robotic procedures have a significantly greater financial cost than laparoscopic gastrectomy, which is a major drawback. Recent clinical studies tried to demonstrate that the benefits of robotic surgery outweighed the cost, but the overall results were disappointing. Ongoing studies are investigating the benefits of robotic gastrectomy in more complicated and challenging cases. Well-designed randomized control trials with large sample sizes are needed to investigate the benefits of robotic gastrectomy compared with laparoscopic surgery.

Robotic surgery for gastric tumor: current status and new approaches

Surgical techniques have evolved tremendously over this past century. To maximize the efficacy and minimize the invasiveness of laparoscopic surgery, researchers have sought to implement wider application of robotics. Nevertheless, both optimism without sound evidence and fear of new technology obscure the appropriate uses of robotic surgery. In the present review, we attempted to provide a balanced perspective on the current state of robotic gastrectomy, outlining evidence and opportunities for the use thereof. Although evidence is limited, the use of robotics is feasible for gastric cancer surgery, and less than 10 cases of robotic surgery are needed to become proficient therein. Compared to the clinical impact of laparoscopy on gastric cancer surgery, the additional benefits of robotic surgery to patients seem to be limited. Despite additional costs and longer surgeries, robotic surgery reportedly does not offer surgical outcomes superior to those for laparoscopic surgery, according to a recent multicenter study. Meanwhile, however, our in-depth review of retrospective and prospective reports revealed that robots could expand the indications of minimally invasive gastrectomy for patients requiring total gastrectomy and D2 lymph node dissection. Moreover, we found that robotic gastrectomy is associated with a higher number of retrieved lymph nodes, less bleeding, fewer complications, and shorter hospital stay, compared to laparoscopic gastrectomy. Accordingly, new surgical approaches using advanced technologies, such as near infrared detectors, the Tilepro^® multi-input display, dual consoles, and the Single-Site^® system, are under investigation. In conclusion, measuring the additional benefits of robotic over laparoscopic surgery would be difficult and clinically insignificant. Thus, developing new surgical procedures that extend the benefits of conventional laparoscopic surgery to patients in whom minimally invasive surgery would not be possible is necessary to justify the greater use of robotic surgery.

Robot-assisted surgery for gastric cancer

Minimally invasive surgery for gastric cancer is a relatively new research field, with convincing results mostly stemming from Asian countries. The use of the robotic surgery platform, thus far assessed as a safe procedure, which is also easier to learn, sets the background for a wider spread of minimally invasive technique in the treatment of gastric cancer. This review will cover the literature published so far, analyzing the pros and cons of robotic surgery and highlighting the remaining study questions.

Increase in Endoscopic and Laparoscopic Surgery Regarding the Therapeutic Approach of Gastric Cancer Detected by Cancer Screening in Saga Prefecture, Japan

Objective Despite recent advances in endoscopic treatment and laparoscopic surgery for gastric cancers, an increase in the uptake of these therapeutic approaches has not yet been fully demonstrated. Therefore, the present study aimed to investigate the change in therapeutic approaches regarding the treatment of gastric cancers detected by cancer screening in Saga Prefecture, Japan between April 2002 and March 2011. Methods Gastric cancer screening by X-ray was performed on 311,074 subjects between April 2002 and March 2011. In total, 534 patients were thereafter diagnosed with gastric cancer. Eighteen subjects were excluded because precise details of their treatment were not available. To evaluate the changes in the therapeutic approach, the observation period was divided into three 3-year intervals: Period I: April 2002 to March 2005; Period II: April 2005 to March 2008; Period III: April 2008 to March 2011. Results The use of open laparotomy for the treatment of gastric cancer decreased, and laparoscopic surgery and endoscopic treatment increased markedly in a time-dependent manner. A 2.5-fold increase in endoscopic treatment, and a 18.4-fold increase in laparoscopic surgery were observed in Period III compared with Period I (after adjusting for age and tumor characteristics). Conclusion Endoscopic treatment and laparoscopic surgery for gastric cancer increased during the investigation period (2002-2011), although the tumor characteristics of the gastric cancers detected through cancer screening in Saga Prefecture, Japan did not show any changes.

Robotic surgery for gastric cancer

Laparoscopic gastrectomy is a widely used minimally invasive surgery for gastric cancer. However, skillful techniques are required to perform lymph node dissection using straight shaped forceps, particularly for D2 dissection. Robotic surgery using the da Vinci surgical system is anticipated to be a powerful tool for performing difficult techniques using high-resolution three-dimensional (3D) images and the EndoWrist equipped with seven degrees of freedom. Attempts are being made to apply robotic surgery in gastrectomy procedures mainly in Japan, South Korea, and Europe. Although definite superiority to laparoscopic gastrectomy is yet to be proven, robotic surgery has been reported to have a shorter learning curve and offer more precise dissection for total gastrectomy. Hence, its oncological efficacy needs to be verified in a clinical trial.

Current status of robotic gastrectomy for gastric cancer

Although over 3000 da Vinci Surgical System (DVSS) devices have been installed worldwide, robotic surgery for gastric cancer has not yet become widely spread and is only available in several advanced institutions. This is because, at least in part, the advantages of robotic surgery for gastric cancer remain unclear. The safety and feasibility of robotic gastrectomy have been demonstrated in several retrospective studies. However, no sound evidence has been reported to support the superiority of a robotic approach for gastric cancer treatment. In addition, the long-term clinical outcomes following robotic gastrectomy have yet to be clarified. Nevertheless, a robotic approach can potentially overcome the disadvantages of conventional laparoscopic surgery if the advantageous functions of this technique are optimized, such as the use of wristed instruments, tremor filtering and high-resolution 3-D images. The potential advantages of robotic gastrectomy have been discussed in several retrospective studies, including the ability to achieve sufficient lymphadenectomy in the area of the splenic hilum, reductions in local complication rates and a shorter learning curve for the robotic approach compared to conventional laparoscopic gastrectomy. In this review, we present the current status and discuss issues regarding robotic gastrectomy for gastric cancer.