Safe implementation of robotic gastrectomy for gastric cancer under the requirements for universal health insurance coverage: a retrospective cohort study using a nationwide registry database in Japan

Impact of a board certification system and adherence to the clinical practice guidelines for gastric cancer on risk-adjusted surgical mortality after distal and total gastrectomy in Japan: a questionnaire survey of departments registered in the National Clinical Database

PURPOSE

The relationship between board certification, clinical guideline implementation, and quality of gastric cancer surgery remains unclear.

METHODS

A web-based questionnaire survey was administered to departments registered in the National Clinical Database (NCD) of Japan between October 2014 and January 2015. Quality indicators (QIs) based on the Donabedian model were evaluated. Structural QIs (e.g., affiliations with academic societies and board certifications) and process QIs (adherence to clinical practice guidelines for gastric cancer) were assessed using risk-adjusted odds ratios (AORs) for surgical mortality. Multivariable logistic regression models with a generalized estimating equation were used.

RESULTS

A total of 835 departments performing 40,992 distal gastrectomies and 806 departments performing 19,618 total gastrectomies responded. Some certified institutions and physicians showed significant associations, with lower AORs for surgical mortality. Important process QIs included pre- and postoperative abdominal CT scanning, endoscopic resection based on progression, curative resection with D2 dissection for advanced gastric cancer, laparoscopic surgery, and HER2 testing for patients with unresectable recurrent gastric cancer.

CONCLUSIONS

Multiple structural and process QIs are associated with surgical mortality after gastrectomy in Japan. Measuring and visualizing QIs may enhance healthcare improvements.

Short-term outcomes of laparoscopic and robotic distal gastrectomy for gastric cancer: Real-world evidence from a large-scale inpatient database in Japan

BACKGROUND AND OBJECTIVES

Robotic distal gastrectomy (RDG) has been widely performed throughout Japan since it became insured in 2018. This study aimed to evaluate the short-term outcomes of RDG and laparoscopic distal gastrectomy (LDG) for gastric cancer using real-world data.

METHODS

A total of 4161 patients who underwent LDG (n = 3173) or RDG (n = 988) for gastric cancer between April 2018 and October 2022 were identified through the Japanese Diagnosis Procedure Combination Database, which covers 42 national university hospitals. The primary outcome was postoperative in-hospital mortality rate. The secondary outcomes were postoperative complication rates, time to diet resumption, and postoperative length of stay (LOS).

RESULTS

In-hospital mortality and postoperative complication rates in the RDG group were comparable with those in the LDG group (0.1% vs. 0.0%, p = 1.000, and 8.7% vs. 8.2%, p = 0.693, respectively). RDG was associated with a longer duration of anesthesia (325 vs. 262 min, p < 0.001), similar time to diet resumption (3 vs. 3 days, p < 0.001), and shorter postoperative LOS (10 vs. 11 days, p < 0.001) compared with LDG.

CONCLUSIONS

RDG was performed safely and provided shorter postoperative LOS, since it became covered by insurance in Japan.

First clinical experiences of robotic gastrectomy for gastric cancer using the hinotori™ surgical robot system

BACKGROUND

Although the da Vinci™ Surgical System is the most predominantly used surgical robot worldwide, other surgical robots are being developed. The Japanese surgical robot hinotori™ Surgical Robot System was launched and approved for clinical use in Japan in November 2022. We performed the first robotic gastrectomy for gastric cancer using hinotori in the world. Here, we report our initial experience and evaluation of the feasibility and safety of robotic gastrectomy for gastric cancer using hinotori.

METHODS

A single-institution retrospective study was conducted. Between November 2022 and October 2023, 24 patients with gastric cancer underwent robotic gastrectomy with hinotori. Five ports, including one for an assistant, were placed in the upper abdomen, and gastric resection with standard lymphadenectomy and intracorporeal reconstruction were performed. The primary endpoint was the postoperative complication rate within 30 days after surgery. The secondary outcomes were surgical outcomes, including intraoperative adverse events, operative time, blood loss, and the number of dissected nodes.

RESULTS

Of the 24 patients, 16 (66.7%) were male. The median age and body mass index were 73.5 years and 22.9 kg/m2, respectively. Twenty-three patients (95.8%) had tumors in the middle to lower stomach. Sixteen (66.7%) and seven (29.2%) patients had clinical stage I and II diseases, respectively. Twenty-three (95.8%) patients underwent distal gastrectomy. No patient had postoperative complications of Clavien-Dindo classification IIIa or higher, whereas two (8.3%) had the grade II complications (enteritis and pneumonia). No intraoperative adverse events, including conversion to other approaches, were observed. All patients received R0 resection. The median operative and console times were 400 and 305 min, respectively. The median blood loss was 14.5 mL, and the number of lymph nodes dissected was 51.5.

CONCLUSIONS

This study found that robotic gastrectomy with standard lymphadenectomy for gastric cancer using hinotori can be safely performed.

Automatic surgical phase recognition-based skill assessment in laparoscopic distal gastrectomy using multicenter videos

BACKGROUND

Gastric surgery involves numerous surgical phases; however, its steps can be clearly defined. Deep learning-based surgical phase recognition can promote stylization of gastric surgery with applications in automatic surgical skill assessment. This study aimed to develop a deep learning-based surgical phase-recognition model using multicenter videos of laparoscopic distal gastrectomy, and examine the feasibility of automatic surgical skill assessment using the developed model.

METHODS

Surgical videos from 20 hospitals were used. Laparoscopic distal gastrectomy was defined and annotated into nine phases and a deep learning-based image classification model was developed for phase recognition. We examined whether the developed model's output, including the number of frames in each phase and the adequacy of the surgical field development during the phase of supra-pancreatic lymphadenectomy, correlated with the manually assigned skill assessment score.

RESULTS

The overall accuracy of phase recognition was 88.8%. Regarding surgical skill assessment based on the number of frames during the phases of lymphadenectomy of the left greater curvature and reconstruction, the number of frames in the high-score group were significantly less than those in the low-score group (829 vs. 1,152, P < 0.01; 1,208 vs. 1,586, P = 0.01, respectively). The output score of the adequacy of the surgical field development, which is the developed model's output, was significantly higher in the high-score group than that in the low-score group (0.975 vs. 0.970, P = 0.04).

CONCLUSION

The developed model had high accuracy in phase-recognition tasks and has the potential for application in automatic surgical skill assessment systems.

Advantages of robotic gastrectomy for overweight patients with gastric cancer: a comparison study of robotic gastrectomy and conventional laparoscopic gastrectomy

PURPOSE

A high body mass index (BMI) generally increases the risk of postoperative complications because of the intraperitoneal adipose tissue. Robotic gastrectomy (RG) decreases the surgical difficulty of conventional laparoscopic gastrectomy (LG) for these patients. We conducted the present study to identify the advantages of RG over LG for overweight patients.

METHODS

We reviewed clinical data on patients who underwent either LG or RG at the National Cancer Center Hospital East between January, 2014 and May, 2022.

RESULTS

The 1298 patients eligible patients were divided into a non-overweight cohort (n = 996) (LG, n = 818; RG, n = 178) and an overweight cohort (n = 302) (LG, n = 250; RG, n = 52) according to a BMI cut-off of 25 kg/m2. In the overweight cohort, the RG group had a lower incidence of grade ≥ III postoperative complications (0.0 vs. 8.8%, p = 0.01) and grade ≥ II postoperative complications (11.5 vs. 22.0%, p = 0.12) than the LG group. Multivariate analysis identified that RG was significantly associated with a lower incidence of grade ≥ II postoperative complications in the overweight cohort (odds ratio, 0.33; 95% confidence interval, 0.12-0.87; p = 0.02).

CONCLUSIONS

RG may reduce the risk of postoperative complications, compared with conventional LG, in overweight patients.

Essential updates 2021/2022: Perioperative and surgical treatments for gastric and esophagogastric junction cancer

In recent years, important clinical trials for gastric cancer (GC) and esophagogastric junction cancer (EGJC) have been reported, changing the strategies of surgical and perioperative treatment. Although laparoscopic gastrectomy has already been shown to be effective for early-stage cancer, recent evidence from both Asia (JLSSG0901, CLASS-01 and KLASS-02) and Europe (LOGICA and STOMACH trials) has demonstrated that it is useful for advanced GC. Robotic surgery has been rapidly gaining popularity in recent years, and randomized controlled trials are ongoing to evaluate its efficacy. A prospective nationwide multicenter study mapped sites with frequent metastasis and revealed lymphatic flow specific to EGJC, thus establishing the optimal lymph node dissection area and surgical approach based on esophageal involvement. Perioperative chemotherapy, the mainstay of treatment in Europe, also has been established in Asia by the PRODIGY and RESOLVE studies. New clinical trials have been conducted to evaluate the efficacy of combining immunotherapy or molecular-targeted therapy with perioperative chemotherapy or chemoradiotherapy. In this review, we present important recent clinical trials regarding the treatment of GC and EGJC published in 2021 or 2022.

Intraoperative performance and outcomes of robotic and laparoscopic total gastrectomy for gastric cancer: A high-volume center retrospective propensity score matching study

BACKGROUND

Studies on robotic total gastrectomy (RTG) are currently limited. This study aimed to compare the intraoperative performance as well as short- and long-term outcomes of RTG and laparoscopic total gastrectomy (LTG).

METHODS

A total of 969 patients underwent robotic (n = 161) or laparoscopic (n = 636) total gastrectomy between October 2014 and October 2021. The two groups of patients were matched 1:3 using the propensity score matching (PSM) method. The intraoperative performance as well as short- and long-term outcomes of the robotic (n = 147) and the laparoscopic (n = 371) groups were compared.

RESULTS

After matching, the estimated intraoperative blood loss was lower (80.51 ± 68.77 vs. 89.89 ± 66.12, p = 0.008), and the total number of lymph node dissections was higher (34.74 ± 12.44 vs. 29.83 ± 12.22, p < 0.001) in the RTG group compared with the LTG group. More lymph node dissections at the upper edge of the pancreas were performed in the RTG group than in the LTG (12.59 ± 4.18 vs. 10.33 ± 4.58, p = 0.001). Additionally, postoperative recovery indicators and laboratory data were greater in the RTG group than those in the LTG group, while postoperative complications were comparable between the two groups (19.0% vs. 18.9%, p = 0.962). For overweight or obese patients with body mass indexes (BMIs) ≥25, certain clinical outcomes of the RTG remained advantageous, and no significant differences in three-year overall survival (OS) or relapse-free survival (RFS) were observed.

CONCLUSIONS

Robotic total gastrectomy demonstrated better intraoperative performance, could improve the short-term clinical outcomes of patients, and was more conducive to patient recovery. However, the long-term efficacies of the two approaches were similar. Robotic surgical systems may reduce surgical stress responses in patients, allowing them to receive postoperative chemotherapy sooner.

Robotic gastrectomy for gastric cancer: systematic review and future directions

BACKGROUND

Robotic gastrectomy (RG) using the da Vinci Surgical System for gastric cancer was approved for national medical insurance coverage in Japan in April 2018, and its number has been rapidly increasing since then.

AIM

We reviewed and compared current evidence on RG and conventional laparoscopic gastrectomy (LG) to identify the differences in surgical outcomes.

METHODS

Three independent reviewers systematically reviewed the data collected from a comprehensive literature search by an independent organization, focusing on the following nine endpoints: mortality, morbidity, operative time, estimated blood loss volume, length of postoperative hospital stay, long-term oncologic outcome, quality of life, learning curve, and cost.

RESULTS

Compared to LG, RG has lower intraoperative blood loss volume, shorter length of hospital stay, and shorter learning curve, but both procedures have similar mortality. Contrarily, its disadvantages include longer procedural time and higher costs. Although the morbidity rate and long-term outcomes are almost comparable, RG showed superior potentials. Currently, the outcomes of RG are considered comparable to or better than LG.

CONCLUSION

RG might be applicable to all gastric cancer patients who fulfill the indication of LG at institutions that meet specific criteria and are approved to claim the National Health Insurance costs for the use of the surgical robot in Japan.

The comparison of short-term outcomes between robotic and laparoscopic radical distal gastrectomy

PURPOSE

The study's objectives were to compare the short-term outcomes of robotic radical distal gastrectomy (RDG) with laparoscopic radical distal gastrectomy (LDG) for patients with gastric cancer and investigate the learning curve of RDG.

METHODS

The cumulative sum (CUSUM) method was used to retrospectively analyze consecutive gastric cancer patients undergoing RDG between January 2019 and October 2021. The duration of surgery, clinical-pathological characteristics, and short-term outcomes were evaluated according to the two phases of the learning curve (learning period versus mastery period). We also compared the clinical-pathological characteristics and short-term outcomes between cases in the mastery period and LDG.

RESULTS

Data from 290 patients were included in this analysis, 135 RDG and 155 LDG cases. The learning period was 20 cases. There were no significant differences in clinical-pathological characteristics between the learning period and mastery period. Compared with the learning period, the mastery period had a significant reduction in total operation time, docking time, pure operation time, and estimated blood loss, and a significant increase in hospital costs (P=0.000, 0.000, 0.000, 0.003, and 0.026, respectively). Compared with LDG, robotic cases in mastery period had a longer operative time, shorter first postoperative flatus time, and more hospital costs (P=0.000, 0.005, and 0.000, respectively).

CONCLUSIONS

RGD may fasten to recover gastrointestinal function faster after the operation, can be mastered easily after a reasonable number of cases, and was associated with safe and satisfactory short-term outcomes before and after the learning curve.

Short-Term and Textbook Surgical Outcomes During the Implementation of a Robotic Gastrectomy Program

BACKGROUND

Whether gastric cancer patients derive greater benefit from robotic gastrectomy (RG), or open gastrectomy (OG) is unknown. We initiated a RG program in 2018, with prospective short-term outcome monitoring to ensure safety. We hypothesized that the RG program for gastric cancer can be safely implemented with equivalent safety and oncological textbook outcomes (TOs) to conventional open gastrectomy (OG).

METHODS

The study included patients who underwent curative-intent OG or RG for gastric adenocarcinoma between January 2018 and December 2021. TO metrics were negative surgical margins, ≥ 15 lymph nodes examined, no severe (Clavien-Dindo grade ≥ IIIa) postoperative complications, no reinterventions within 90 days after surgery, no ICU admission, no prolonged length of stay (LOS; > 10 days), no 90-day postoperative mortality, and no readmission within 90 days after surgery. Overall TO was achieved when all these metrics were met.

RESULTS

Of 161 patients, 120 underwent OG, and 41 underwent RG. The two groups' demographic and disease characteristics did not differ significantly. Compared with OG patients, RG patients had a longer median surgery time (348 vs. 282 min), smaller median blood loss volume (50 vs. 150 mL), lower mean prescribed opioid dose at discharge (12 vs. 45 mg), and shorter median LOS (4 vs. 7 days; all p < 0.001). The groups' postoperative complication rates (10% vs. 17%) did not differ significantly (p = 0.283). The overall TO rate of the RG group (73%) was higher than that of the OG group (60%), but the difference was not significant (p = 0.131).

CONCLUSION

We were able to implement the RG program safely, without compromising safety or oncological outcomes.

Evaluation of surgical complexity by automated surgical process recognition in robotic distal gastrectomy using artificial intelligence

BACKGROUND

Although radical gastrectomy with lymph node dissection is the standard treatment for gastric cancer, the complication rate remains high. Thus, estimation of surgical complexity is required for safety. We aim to investigate the association between the surgical process and complexity, such as a risk of complications in robotic distal gastrectomy (RDG), to establish an artificial intelligence (AI)-based automated surgical phase recognition by analyzing robotic surgical videos, and to investigate the predictability of surgical complexity by AI.

METHOD

This study assessed clinical data and robotic surgical videos for 56 patients who underwent RDG for gastric cancer. We investigated (1) the relationship between surgical complexity and perioperative factors (patient characteristics, surgical process); (2) AI training for automated phase recognition and model performance was assessed by comparing predictions to the surgeon-annotated reference; (3) AI model predictability for surgical complexity was calculated by the area under the curve.

RESULT

Surgical complexity score comprised extended total surgical duration, bleeding, and complications and was strongly associated with the intraoperative surgical process, especially in the beginning phases (area under the curve 0.913). We established an AI model that can recognize surgical phases from video with 87% accuracy; AI can determine intraoperative surgical complexity by calculating the duration of beginning phases from phases 1-3 (area under the curve 0.859).

CONCLUSION

Surgical complexity, as a surrogate of short-term outcomes, can be predicted by the surgical process, especially in the extended duration of beginning phases. Surgical complexity can also be evaluated with automation using our artificial intelligence-based model.

Three-year outcomes of robotic gastrectomy versus laparoscopic gastrectomy for the treatment of clinical stage I/II gastric cancer: a multi-institutional retrospective comparative study

BACKGROUND

Oncological benefits of robotic gastrectomy (RG) remain unclear. We aimed to determine and compare the 3-year outcomes of RG and laparoscopic gastrectomy (LG) for the treatment of gastric cancer.

METHODS

This was a multi-institutional retrospective study of patients who prospectively underwent RG in a previous study (UMIN000015388) and historical controls who underwent LG. Operable patients with cStage I/II primary gastric cancer were enrolled. The inverse probability of treatment weighting method based on propensity scores was used to balance patient demographic factors and surgeon volume between the RG and LG groups. The primary outcome measure was the 3-year overall survival rate (3yOS).

RESULTS

Of the 1,127 patients in the previous study, 326 and 752 patients in the RG and LG groups, respectively, completed the study. The standardized difference of all confounding factors was reduced to 0.09 or less after weighting. In the weighted population, 3yOS was 96.3% and 89.6% in the RG and LG groups, respectively (hazard ratio [HR] 0.34 [0.15, 0.76]; p = 0.009), whereas there was no difference in 3-year recurrence-free survival rate (3yRFS) between the two groups (HR 0.58 [0.32, 1.05]; p = 0.073). Sub-analyses showed that RG improved 3yOS (HR 0.05 [0.01, 0.38]; p = 0.004) and 3yRFS (HR 0.05 [0.01, 0.34]; p = 0.003) in patients with pStage IA disease. Recurrence rates and patterns were similar between the RG and LG groups. RG did not improve the morbidity rate, however, it attenuated some of the adverse events, including anastomotic leakage and intra-abdominal abscess. RG improved estimated blood loss and duration of postoperative hospitalization.

CONCLUSION

This study showed surgical and oncological safety of RG for cStage I/II gastric cancer considering the 3-year outcomes, compared with those of LG.

Clinical advantage of standardized robotic total gastrectomy for gastric cancer: a single-center retrospective cohort study using propensity-score matching analysis

BACKGROUND

Although recent studies have shown that robotic gastrectomy offers clinical advantages over laparoscopic gastrectomy in decreasing gastric cancer (GC) morbidity, studies focusing on robotic total gastrectomy (RTG) remain limited. The current study aimed to clarify whether the use of a robotic system could clinically improve short-term outcomes.

METHODS

Between January 2009 and June 2021, 371 patients diagnosed with both clinical and pathological Stage III or lower GC and underwent RTG or laparoscopic total gastrectomy (LTG) were enrolled in this study. The primary outcome was the incidence of intra-abdominal infectious complications over Clavien-Dindo classification grade IIIa. Demographic characteristics of those who underwent the RTG and LTG were matched using propensity-score matching (PSM), after which short-term outcomes were compared retrospectively.

RESULTS

After PSM, 100 patients were included in each group. The RTG group had a significantly shorter duration of hospitalization following surgery [RTG 13 (11-16) days vs. LTG 14 (11-19) days; p = 0.032] and a greater number of dissected LNs [RTG 48 (39-59) vs. LTG 43 (35-54) mL; p = 0.025], despite having a greater total operative time [RTG 511 (450-646) min vs. LTG 448 (387-549) min; p < 0.001]. In addition, the RTG group had significantly fewer total complications (3% vs. 13%, p = 0.019) and intra-abdominal infectious complications (1% vs. 9%; p = 0.023).

CONCLUSIONS

The current study showed that robotic surgery might improve short-term outcomes following minimally invasive radical total gastrectomy by reducing intra-abdominal infectious complications.

Prognostic impact of LY6K and CDCA1 expression for patients with esophageal squamous cell carcinoma

AIM

In the present study, we investigated the relationship between the expressions of two cancer testis antigens (CTA), LY6K (lymphocyte antigen 6 complex locus K) and CDCA1 (cell division cycle associated 1), in esophageal squamous cell carcinoma (ESCC) tumors and the long-term outcomes of patients with ESCC to clarify the clinical significance of LY6K and CDCA1 expression in ESCC tumors.

METHODS

A total of 175 patients with thoracic ESCC who had undergone a thoracic esophagectomy with three-field lymphadenectomy without neoadjuvant therapy were retrospectively reviewed in this study. LY6K and CDCA1 expressions were evaluated in tumor tissues using immunohistochemical (IH) staining.

RESULTS

Median patient age was 63 years; 159 patients (90.9%) were men. Ninety-four patients (55.3%) were LY6K-positive, and 85 patients (48.6%) were CDCA1-positive. The LY6K-positive group had a significantly worse overall survival (OS) than the LY6K-negative group (P = 0.012), and the CDCA1-positive group had a significantly worse OS than the CDCA1-negative group (P = 0.010). A multivariate analysis suggested that pathological N stage, venous invasion, LK6Y-positive and CDCA1-positive were independent prognostic factors. The patients were classified into four groups according to the staining pattern combinations of the two CTA. The LY6K-positive and CDCA1-positive group was found to have a significantly poorer outcome than the other groups.

CONCLUSION

ESCC patients with a combination of LY6K and CDCA1 expression in their tumor tissues had a worse prognosis than all the other ESCC patients and it was an independent factor associated with prognosis for patients with ESCC.