The sixth edition of the Japanese Gastric Cancer Treatment Guidelines was completed in July 2021, incorporating new evidence that emerged after publication of the previous edition. It consists of a ...text-based “Treatments” part and a “Clinical Questions” part including recommendations and explanations for clinical questions. The treatments parts include a comprehensive description regarding surgery, endoscopic resection and chemotherapy for gastric cancer. The clinical question part is based on the literature search and evaluation by an independent systematic review team. Consequently, not only evidence for each therapeutic recommendation was clearly shown, but it also identified the research fields that require further evaluation to provide appropriate recommendations.
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.
Background
Robotic gastrectomy (RG) for gastric cancer (GC) has been increasingly performed for a decade; however, evidence for its use as a standard treatment has not yet been established. The ...present study aimed to determine the safety, feasibility, and effectiveness of RG for GC.
Methods
This multi-institutional, single-arm prospective study, which included 330 patients from 15 institutions, was designed to compare morbidity rate of RG with that of a historical control (conventional laparoscopic gastrectomy, LG). This trial was approved for Advanced Medical Technology (“Senshiniryo”) B. The included patients were operable patients with cStage I/II GC. The primary endpoint was morbidity (Clavien–Dindo Grade ≥ IIIa). The specific hypothesis was that RG could reduce the morbidity rate to less than half of that with LG (6.4%). A sample size of 330 was considered sufficient (one-sided alpha 0.05, power 80%).
Results
Among the 330 study patients, the protocol treatment was suspended in 4 patients. Thus, 326 patients fully enrolled and completed the study. The median patient age and BMI were 66 years and 22.4 kg/m
2
, respectively. Distal gastrectomy was performed in 253 (77.6%) patients. The median operative time and estimated blood loss were 313 min and 20 mL, respectively. No 30-day mortality was seen, and morbidity showed a significant reduction to 2.45% with RG (
p
= 0.0018).
Conclusions
RG for cStage I/II GC is safe and feasible. It may be effective in reducing morbidity with LG.
Background
While endoscopic submucosal dissection (ESD) is recognized as a minimally invasive standard treatment for differentiated early gastric cancers (EGCs), it has not been indicated for ...undifferentiated EGC (UD-EGC) because of a relatively high risk of lymph node metastasis (LNM). However, patients with surgically resected mucosal (cT1a) UD-EGC ≤ 2 cm in size with no lymphovascular invasion or ulceration are reported to be at a very low risk of LNM. This multicenter, single-arm, confirmatory trial was conducted to evaluate the efficacy and safety of ESD for UD-EGC.
Methods
The key eligibility criteria were endoscopically diagnosed cT1a/N0/M0, single primary lesion, size ≤ 2 cm, no ulceration and histologically proven components of undifferentiated adenocarcinoma on biopsy. Based on the histological findings after ESD, additional gastrectomy was indicated if the criteria for curative resection were not satisfied. The subjects of the primary analysis were patients with UD-EGC as the dominant component. The primary endpoint was 5-year overall survival (OS) of patients with UD-EGC.
Results
Three hundred 46 patients were enrolled from 49 institutions. The proportion of
en bloc
resection was 99%. No ESD-related Grade 4 adverse events were noted. Delayed bleeding and intraoperative and delayed perforation occurred in 25 (7.3%), 13 (3.8%), and 6 (1.7%) patients, respectively. Among the 275 patients who were the subjects of the primary analysis, curative resection was achieved in 195 patients (71%), and 5-year OS was 99.3% (95% CI: 97.1–99.8).
Conclusions
ESD can be a curative and less invasive treatment for UD-EGC for patients meeting the eligibility criteria of this study.
Recently, immune checkpoint inhibitors such as anti-programmed cell death-1 (PD-1) or programmed cell death ligand-1 (PD-L1) monoclonal antibodies have improved the overall survival of various types ...of cancers including advanced gastric cancer (AGC). Until now, two ant-PD-1 inhibitors were approved for AGC in Japan: nivolumab as third- or later-line treatment for AGC and pembrolizumab for previously treated patients with microsatellite instability-high tumours. However, a limited number of patients achieved clinical benefit, highlighting the importance of the better selection of patients or additional treatment to overcome resistance to PD-1/PD-L1 blockade. This review focused on pivotal clinical trials, biomarkers and novel combination therapy of immune checkpoint inhibitors forAGC.
Background
Formalin-fixed, paraffin-embedded (FFPE) samples acquired and preserved adequately are expected to faithfully maintain tumor characteristics. Endoscopic biopsy tissues represent an ...attractive resource for identifying predictive biomarkers to evaluate pretreatment responses of patients with advanced gastric cancer (GC). However, whether genomic profiles obtained through next-generation sequencing (NGS) using biopsy samples match well with those gained from surgical FFPE samples remains a concern.
Methods
We collected 50 FFPE samples (26 biopsies and 24 surgical samples) from patients with GC who participated in phase III clinical trial JCOG1509. The quality and quantity of FFPE samples were determined for deep sequencing using NGS. We queried a 435-gene panel CANCERPLEX-JP to generate comprehensive genomic profiling data including the tumor mutation burden (TMB).
Results
The median DNA yields and NGS success rates of biopsy samples compared with surgical samples were 879 ng and 80.8% vs 8523 ng and 100%, respectively. Epstein-Barr virus and microsatellite instability-high were detected in 9.5% of biopsy samples. Comparing the genomic profiles of 18 paired samples for which NGS data were available, we detected identical somatic mutations in paired biopsy and surgical samples (kappa coefficient, 0.8692). TMB positively correlated between paired biopsy and surgical samples (correlation coefficient, 0.6911).
Conclusions
NGS is applicable to the analysis of FFPE samples of GC acquired by the endoscopic biopsy, and the data were highly concordant with those obtained from surgical specimens of the same patients.
Background
Preoperative malnutrition can worsen morbidity and mortality; however, the role of postgastrectomy nutritional status remains unclear. Our purpose was to clarify whether malnutrition after ...gastrectomy could predict long-term survival.
Methods
Patients with pathological stage I, II, and III gastric cancer who underwent gastrectomy between 2002 and 2013 were included. The nutrition risk index (NRI) was evaluated before and at 1, 3, 6 and 12 months after gastrectomy. The patients were divided into normal (NRI > 97.5) or malnutrition (NRI ≤ 97.5) groups, and we compared the correlations of clinicopathological characteristics, surgical treatment, and overall survival between the two groups.
Results
Among the 760 participants, patients in the malnutrition group were significantly older and had higher incidences of comorbidity and advanced cancer than the patients in the normal group. Multivariate analysis showed that overall survival was poorer in the malnutrition group before gastrectomy hazard ratio (HR) 1.68 and at 1 month (HR 1.77), 3 months (HR 2.18), 6 months (HR 1.81) and 12 months (HR 2.17) after gastrectomy (all
p
< 0.01). Malnutrition at 1 and 3 months after gastrectomy was significantly associated with poor cause-specific survival. Total gastrectomy, preoperative malnutrition, older age, and adjuvant chemotherapy were independent risk factors of postoperative malnutrition at 12 months postgastrectomy.
Conclusions
Malnutrition before gastrectomy and at 1, 3, 6 and 12 months after gastrectomy significantly and adversely affects overall survival. Nutritional interventions to lessen the impact of postoperative malnutrition offer hope for prolonged survival.
Backgrounds
Laparoscopy-assisted distal gastrectomy (LADG) for gastric cancer is safe and feasible. In contrast, no prospective study evaluating the safety and efficacy of laparoscopy-assisted total ...gastrectomy (LATG) or laparoscopy-assisted proximal gastrectomy (LAPG) has been completed. We conducted a single-arm confirmatory trial to evaluate the safety of LATG/LAPG for clinical stage I (T1N0/T1N1/T2N0) proximal gastric cancer.
Methods
The extent of lymphadenectomy was selected based on the Japanese Gastric Cancer Treatment Guidelines. The mini-laparotomy incision was required to be ≤ 6 cm. The primary endpoint was the proportion of grade 2–4 (CTCAE ver. 4.0) esophagojejunal anastomotic leakage. The planned sample size was 245 considering a threshold of 8% and one-sided alpha of 2.5%.
Results
Between April 2015 and February 2017, 244 eligible patients were enrolled. LATG/LAPG was performed in 195/49. The proportion of conversions was 1.7%. Clinical T1N0/T1N1/T2N0 was 212/9/23. The extents of lymphadenectomy were as follows: D1+: 229; D2: 15. The median operation time was 309 min (IQR 265–353). The median blood loss was 30 ml (IQR 10–86). Grade 2–4 esophagojejunal anastomotic leakage was 2.5% (6/244; 95% CI 0.9–5.3). The overall proportion of in-hospital grade 3–4 adverse events was 29% (71/244). The proportions of intraabdominal abscess and pancreatic fistula were 3.7% and 2.0%, respectively. There were no treatment-related deaths.
Conclusions
This trial confirmed the safety of LATG/LAPG. After the non-inferiority of LADG is confirmed in our phase III trial (JCOG0912), LATG/LAPG is expected to be established as one of the standard treatments for clinical stage I gastric cancer.
Background
Recent studies have found a negative impact of postoperative complications on long-term survival outcomes, but it has not been confirmed by data obtained from a prospective study with a ...large sample size. This study investigated the impact of postoperative complications on long-term survival outcomes, and considered the optimal definition of complication, using data from JCOG1001, which compared bursectomy and non-bursectomy for patients with cT3/4a locally advanced gastric cancer.
Methods
This study included 1191 of 1204 patients enrolled in the JCOG1001 trial. Complications were graded by Clavien–Dindo (C-D) classification. Impact of the grade (≥ C-D grade II or ≥ grade III) or type (any or intra-abdominal infectious) of complication on survival outcome was evaluated by univariate and multivariable analyses using the Cox proportional hazard model.
Results
The incidence of any ≥ C-D grade II and ≥ grade III complication was 23.0% and 9.7%, respectively, and that of ≥ grade II and ≥ grade III intra-abdominal infectious complication was 13.4% and 6.9%, respectively. Multivariable analysis showed all four definitions of complications were independent prognostic factors for overall survival. Conversely, only any ≥ C-D grade III complication was found to be an independent prognostic factor for relapse-free survival (hazard ratio, 1.445; 95% confidence interval, 1.026–2.036;
P
= 0.035).
Conclusions
Postoperative complications adversely affect the long-term survival outcomes of patients with cT3/4a gastric cancer. Any ≥ C-D grade III complication seems to be the most suitable definition of complication for predicting negative long-term survival outcomes.
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