Organ-specific variations in tumor marker dynamics in postoperative pancreatic cancer recurrence: Trends in lung and liver recurrence highlighting biological heterogeneity.

BACKGROUND/OBJECTIVES: Although tumor recurrence after surgical resection in pancreatic cancer (PC) is generally considered incurable, it is well-accepted that clinical presentations and outcomes vary according to the recurrent sites (e.g., liver vs. lung recurrence), suggesting a possible biological inhomogeneity of PC recurrence. Understanding the behavior of biological factors, specifically tumor markers (TMs), at different recurrence sites may contribute to individualized treatment strategies. Therefore, this study aimed to compare the dynamics of pre-recurrence TMs at liver and lung recurrence sites. METHODS: Patients with isolated postoperative liver or lung recurrence as their first recurrence were enrolled. Starting from the recurrence date confirmed by imaging examinations, the values of TMs (carbohydrate antigen 19-9: CA19-9; carcinoembryonic antigen: CEA) were retrospectively evaluated 6 and 3 months before recurrence and at the time of recurrence. RESULTS: Patients with liver recurrence displayed a significant increase in CA19-9 and CEA levels from as early as 6 months before recurrence. Contrastingly, patients with lung recurrence demonstrated a significant elevation of CA19-9 levels starting from 3 months before recurrence, with no increase in CEA levels, even at the time of recurrence. The relative change in CA19-9 and CEA levels during each period were significantly lower in patients with lung recurrence. CONCLUSIONS: Both TMs exhibited organ-specific variations in patients with postoperative PC recurrence. This disparity may reflect the biological heterogeneity of PC between recurrence patterns, thereby highlighting the importance of conducting postoperative follow-up with consideration of this fact.

A phase 3, randomized, double-blind, multicenter, placebo-controlled study of S-588410, a five-peptide cancer vaccine as an adjuvant therapy after curative resection in patients with esophageal squamous cell carcinoma.

BACKGROUND: S-588410, a cancer peptide vaccine (CPV), comprises five HLA-A*24:02-restricted peptides from five cancer-testis antigens. In a phase 2 study, S-588410 was well-tolerated and exhibited antitumor efficacy in patients with urothelial cancer. Therefore, we aimed to evaluate the efficacy, immune response, and safety of S-588410 in patients with completely resected esophageal squamous cell carcinoma (ESCC). METHODS: This phase 3 study involved patients with HLA-A*24:02-positive and lymph node metastasis-positive ESCC who received neoadjuvant therapy followed by curative resection. After randomization, patients were administered S-588410 and placebo (both emulsified with Montanide™ ISA 51VG) subcutaneously. The primary endpoint was relapse-free survival (RFS). The secondary endpoints were overall survival (OS), cytotoxic T-lymphocyte (CTL) induction, and safety. Statistical significance was tested using the one-sided weighted log-rank test with the Fleming-Harrington class of weights. RESULTS: A total of 276 patients were randomized (N = 138/group). The median RFS was 84.3 and 84.1 weeks in the S-588410 and placebo groups, respectively (P = 0.8156), whereas the median OS was 236.3 weeks and not reached, respectively (P = 0.6533). CTL induction was observed in 132/134 (98.5%) patients who received S-588410 within 12 weeks. Injection site reactions (137/140 patients [97.9%]) were the most frequent treatment-emergent adverse events in the S-588410 group. Prolonged survival was observed in S-588410-treated patients with upper thoracic ESCC, grade 3 injection-site reactions, or high CTL intensity. CONCLUSIONS: S-588410 induced immune response and had acceptable safety but failed to reach the primary endpoint. A high CTL induction rate and intensity may be critical for prolonging survival during future CPV development.

Pancreas-left gastric artery angle predicts difficulty of suprapancreatic lymph node dissection in gastrectomy for gastric cancer: a cross-sectional study.

PURPOSE: Suprapancreatic lymph node dissection is one of the most challenging procedures performed in the treatment of gastric cancer. This study aimed to investigate whether the pancreas-left gastric artery angle (PLA) can be used to predict the difficulty of the procedure. METHODS: This was a single-center cross-sectional study. Before gastrectomy, the patients were classified according to the size of the PLA into the small PLA (s-PLA; < 30°) and large PLA (l-PLA; ≥ 30°) groups in a surgeon-blinded manner. After gastrectomy, a surgeon evaluated suprapancreatic lymph node dissection as hard, normal, or easy to perform. RESULTS: Seventy-three patients were enrolled in the study. Surgeons evaluated lymph node dissection as hard in 43.8 and 8.7% of patients in the s-PLA and l-PLA groups, respectively (p = 0.002). The time taken for suprapancreatic lymph node dissection was also significantly longer in the s-PLA group than in the l-PLA group (p = 0.040). In patients who underwent laparoscopic gastrectomy, the time for node dissection in the s-PLA group was also significantly longer than that in the s-PLA group (p = 0.021), while there was no difference in those who underwent robotic surgery (p = 0.815). CONCLUSION: PLA is useful for predicting the degree of difficulty of suprapancreatic lymph node dissection during gastrectomy for gastric cancer.

[The Power of the Gut Microbiome: Exploring New Perspectives in Colorectal Cancer Therapy].

The gut microbiome is involved in host physiology, including nutrition, metabolism, and immunity. It was recently known that dysbiosis of the gut microbiome has been implicated in several human diseases such as inflammatory bowel disease. It is altered by environmental factors such as diet, habit and lifestyle and has been directly and indirectly linked to the development and progression of colorectal cancer(CRC). Fusobacterium(F.)nucleatum, which causes periodontal disease, has been shown to play an important role in the initiation and development of CRC, although not as clearly as Helicobacter(H.) pylori in gastric cancer. Therefore, gut bacteria hold promise as a potential therapeutic approach to prevent or treat CRC. Although its clinical usefulness has not yet been demonstrated, future research such as metagenomics may open new avenues for CRC treatment with gut bacteria. Here, we reviewed the role of the gut microbial community in the development, progression, and prevention of colorectal carcinogenesis.

Long-Term Effects of Oral Nutritional Supplements After Gastrectomy for Gastric Cancer: A Survival Analysis from a Multicenter, Open-Label, Randomized Controlled Trial.

BACKGROUND: Weight loss (WL) after gastrectomy for gastric cancer is associated with both decreased compliance with adjuvant chemotherapy and impaired survival. This study examined the effects of administering oral nutritional supplements (ONS) for 3 months after gastrectomy in terms of compliance with adjuvant chemotherapy and survival outcomes. METHODS: This large-scale, multicenter, open-label, randomized controlled trial enrolled 1,003 gastric cancer patients undergoing curative gastrectomy. Patients were assigned to the control group (n = 503) or ONS group (n = 500). In the ONS group, 400 kcal/day of ONS was recommended in addition to a regular diet for 3 months after gastrectomy. Compliance with adjuvant chemotherapy and survival outcomes were compared between the two groups. RESULTS: Compared with the control group, the ONS group showed significantly decreased WL at 3 months after gastrectomy (8.6 ± 6.1 vs. 7.2 ± 5.7%, respectively, P = 0.0004). The control and ONS groups did not differ regarding the induction rate of adjuvant chemotherapy (84.9 vs. 82.8%, respectively, P = 0.614) or the continuation rate at 3 months postoperatively (75.3 vs. 76.6%, respectively, P = 0.809). Oral nutritional supplements for 3 months showed no survival benefit; the 3- and 5-year overall survival (OS) rates were 91.3% and 87.6% in the control group and 89.6% and 86.4% in the ONS group, respectively, indicating no significant difference (P = 0.548). Subgroup analysis could not detect a population in which ONS administration increased OS. CONCLUSIONS: Administration of ONS for 3 months after gastrectomy was not associated with increased compliance with adjuvant chemotherapy or with improved prognosis.

Significance of signal recognition particle 9 nuclear translocation: Implications for pancreatic cancer prognosis and functionality.

Signal recognition particles (SRPs) are essential for regulating intracellular protein transport and secretion. Patients with tumors with high SRP9 expression tend to have a poorer overall survival. However, to the best of our knowledge, no reports have described the relationship between SRP9 localization and prognosis in pancreatic cancer. Thus, the present study aimed to investigate this relationship. Immunohistochemical staining for SRP9 using excised specimens from pancreatic cancer surgery cases without preoperative chemotherapy or radiotherapy showed that SRP9 was preferentially expressed in the nucleus of the cancerous regions in some cases, which was hardly detected in other cases, indicating that SRP9 was transported to the nucleus in the former cases. To compare the prognosis of patients with SRP9 nuclear translocation, patients were divided into two groups: Those with a nuclear translocation rate of >50% and those with a nuclear translocation rate of ≤50%. The nuclear translocation rate of >50% group had a significantly better recurrence­free survival than the nuclear translocation rate of ≤50% group (P=0.037). Subsequent in vitro experiments were conducted; notably, the nuclear translocation rate of SRP9 was reduced under amino acid­deficient conditions, suggesting that multiple factors are involved in this phenomenon. To further study the function of SRP9 nuclear translocation, in vitro experiments were performed by introducing SRP9 splicing variants (v1 and v2) and their deletion mutants lacking C­terminal regions into MiaPaCa pancreatic cancer cells. The results demonstrated that both splicing variants showed nuclear translocation regardless of the C­terminal deletions, suggesting the role of the N­terminal regions. Given that SRP9 is an RNA­binding protein, the study of RNA immunoprecipitation revealed that signaling pathways involved in cancer progression and protein translation were downregulated in nuclear­translocated v1 and v2. Undoubtedly, further studies of the nuclear translocation of SRP9 will open an avenue to optimize the precise evaluation and therapeutic control of pancreatic cancer.

Tissue-Resident Memory T Cells in Gastrointestinal Cancers: Prognostic Significance and Therapeutic Implications.

Gastrointestinal cancers, which include a variety of esophageal and colorectal malignancies, present a global health challenge and require effective treatment strategies. In the evolving field of cancer immunotherapy, tissue-resident memory T cells (Trm cells) have emerged as important players in the immune response within nonlymphoid tissues. In this review, we summarize the characteristics and functions of Trm cells and discuss their profound implications for patient outcomes in gastrointestinal cancers. Positioned strategically in peripheral tissues, Trm cells have functions beyond immune surveillance, affecting tumor progression, prognosis, and response to immunotherapy. Studies indicate that Trm cells are prognostic markers and correlate positively with enhanced survival. Their presence in the tumor microenvironment has sparked interest in their therapeutic potential, particularly with respect to immune checkpoint inhibitors, which may improve cancer treatment. Understanding how Trm cells work will not only help to prevent cancer spread through effective treatment but will also contribute to disease prevention at early stages as well as vaccine development. The role of Trm cells goes beyond just cancer, and they have potential applications in infectious and autoimmune diseases. This review provides a thorough analysis of Trm cells in gastrointestinal cancers, which may lead to personalized and effective cancer therapies.

Surgical and Perioperative Treatments for Esophagogastric Junction Cancer.

Esophagogastric junction cancer (EGJC) is a rare malignant disease that occurs in the gastroesophageal transition zone. In recent years, its incidence has been rapidly increasing not only in Western countries but also in East Asia, and it has been attracting the attention of both clinicians and researchers. EGJC has a worse prognosis than gastric cancer (GC) and is characterized by complex lymphatic drainage pathways in the mediastinal and abdominal regions. EGJC was previously treated in the same way as GC or esophageal cancer, but, in recent years, it has been treated as an independent malignant disease, and treatment focusing only on EGJC has been developed. A recent multicenter prospective study revealed the frequency of lymph node metastasis by station and established the optimal extent of lymph node dissection. In perioperative treatment, the combination of multi-drug chemotherapy, radiation therapy, molecular targeted therapy, and immunotherapy is expected to improve the prognosis. In this review, we summarize previous clinical trials and their important evidence on surgical and perioperative treatments for EGJC.

Clinical significance of ribosomal protein S15 expression in patients with colorectal cancer liver metastases.

BACKGROUND: Liver metastasis is the most frequently observed distant metastasis of colorectal cancer, and the residual liver recurrence rate after hepatic resection is still high. To explore the mechanism of liver metastasis to discover potential new treatments, we assessed the relationship between the expression of differentially expressed genes (DEGs) and prognosis in patients with colorectal cancer liver metastasis (CRLM). METHODS: The gene expression dataset was extracted from The Cancer Genome Atlas and the Gene Expression Omnibus. Significance analysis of DEGs between tumor and normal samples of colorectum, liver, and lung was conducted. A total of 80 CRLM patients were studied to assess the expression of RPS15, characteristics, and outcomes. We examined the relationships of RPS15 expression to cell viability and apoptosis in vitro and vivo. RESULTS: Significance analysis identified 33 DEGs. In our cohorts, the overall survival rates were significantly lower in the high-RPS15-expression group, and high expression of RPS15 was an independent and unfavorable prognostic factor in recurrence-free survival and overall survival. Knockdown of RPS15 expression reduced the proliferative capacity of colorectal cancer cells and increased BAX-induced apoptotic cell death. CONCLUSIONS: RPS15 expression is an independent prognostic factor for CRLM patients and might be a novel therapeutic target for CRLM.

BRAF V600E-induced distinct DNA damage response defines the therapeutic potential of p53 activation for TP53 wild-type colorectal cancer.

BRAF V600E, one of the most frequent mutations in the MAPK pathway, confers poor prognosis to colorectal cancers (CRCs), partly because of chemotherapeutic resistance. Oncogene-induced DNA damage responses (DDRs) that primarily activate p53 are important mechanistic barriers to the malignant transformation of cells; however, the mechanism underlying this impairment in cancer remains unknown. Here, we evaluated the responses of BRAFV600E-induced DDRs in two CRC cell lines, SW48 and LIM1215, both of which harbor wild-type TP53, KRAS, and BRAF. BRAFV600E transduction exhibited distinct phenotypes in these cells: SW48 cell proliferation markedly decreased, whereas that of LIM1215 increased. BRAFV600E expression induced the activation of oncogene-induced DDR signaling in SW48 cells, but not in LIM1215 cells, whereas chemotherapeutic agents similarly activated DDRs in both cell lines. Knockdown experiments revealed that these responses in SW48 cells were mediated by p53-p21 pathway activation. Comet assay (both alkaline and neutral) revealed that BRAFV600E increased single-strand breaks to the same extent in both cell lines; however, in case of LIM1215 cells, it only facilitated double-strand breaks. Furthermore, the proliferation of LIM1215 cells, wherein no oncogene-induced DDRs occurred, was synergistically inhibited upon MDM2 inhibitor-mediated p53 activation combined with MEK inhibition. Taken together, these distinct DDR signaling responses highlight the novel characteristics of BRAFV600E-mutated CRC cells and define the therapeutic potential of p53 activation combined with MAPK inhibition against TP53 wild-type CRC harboring a BRAFV600E mutation.

Efficacy and survival of nivolumab treatment for recurrent/unresectable esophageal squamous-cell carcinoma: real-world clinical data from a large multi-institutional cohort.

BACKGROUND: Real-world clinical outcomes of and prognostic factors for nivolumab treatment for esophageal squamous-cell carcinoma (ESCC) remain unclear. This study aimed to evaluate real-world outcomes of nivolumab monotherapy in association with relevant clinical parameters in recurrent/unresectable advanced ESCC patients. METHODS: This population-based multicenter cohort study included a total of 282 patients from 15 institutions with recurrent/unresectable advanced ESCC who received nivolumab as a second-line or later therapy between 2014 and 2022. Data, including the best overall response, progression-free survival (PFS), and overall survival (OS), were retrospectively collected from these patients. RESULTS: Objective response and disease control rates were 17.0% and 47.9%, respectively. The clinical response to nivolumab treatment significantly correlated with development of overall immune-related adverse events (P < .0001), including rash (P < .0001), hypothyroidism (P = .03), and interstitial pneumonia (P = .004). Organ-specific best response rates were 20.6% in lymph nodes, 17.4% in lungs, 15.4% in pleural dissemination, and 13.6% in primary lesions. In terms of patient survival, the median OS and PFS was 10.9 and 2.4 months, respectively. Univariate analysis of OS revealed that performance status (PS; P < .0001), number of metastatic organs (P = .019), C-reactive protein-to-albumin ratio (CAR; P < .0001), neutrophil-lymphocyte ratio (P = .001), and PMI (P = .024) were significant. Multivariate analysis further identified CAR [hazard ratio (HR) = 1.61, 95% confidence interval (CI) 1.15-2.25, P = .0053)] in addition to PS (HR = 1.65, 95% CI 1.23-2.22, P = .0008) as independent prognostic parameters. CONCLUSIONS: CAR and PS before nivolumab treatment are useful in predicting long-term survival in recurrent/unresectable advanced ESCC patients with second-line or later nivolumab treatment. TRIAL REGISTRATION: UMIN000040462.

The combination of gemcitabine plus an anti-FGFR inhibitor can have a synergistic antitumor effect on FGF-activating cholangiocarcinoma.

Anti-FGFR treatment for cholangiocarcinoma (CCA) with fibroblast growth factor receptor (FGFR) alteration is a promising treatment option. Since the antitumor mechanisms of anti-FGFR inhibitors and conventional cytotoxic drugs differ, synergistic effects can be possible. This study aimed to evaluate the efficacy of the combined administration of gemcitabine (GEM) and pemigatinib in CCA cells with FGFR2 alterations. To simulate the treatment for patients with 3 kinds of CCA, chemonaïve CCA with activation of the FGF pathway, chemo-resistant CCA with activation of the FGF pathway, and CCA without FGF pathway activation (as controls), we evaluated 3 different CCA cell lines, CCLP-1 (with a FGFR2 fusion mutation), CCLP-GR (GEM-resistant cells established from CCLP-1), and HuCCT1 (without FGFR mutations). There was no significant difference between CCLP-1 and HuCCT1 in GEM suspensibility (IC50 = 19.3, 22.6 mg/dl, p = 0.1187), and the drug sensitivity to pemigatinib did not differ between CCLP-1 and CCLP-GR (IC50 = 7.18,7.60 nM, p = 0.3089). Interestingly, only CCLP-1 showed a synergistic effect with combination therapy consisting of GEM plus pemigatinib in vitro and in vivo. In a comparison of the reaction to GEM exposure, only CCLP-1 cells showed an increase in the activation of downstream proteins in the FGF pathway, especially FRS2 and ERK. In association with this reaction, cell cycle and mitosis were increased with GEM exposure in CCLP-1, but HuCCT1/CCLP-GR did not show this reaction. Our results suggested that combination therapy with GEM plus pemigatinib is a promising treatment for chemonaïve patients with CCA with activation of the FGF pathway.

Nivolumab plus chemotherapy or ipilimumab versus chemotherapy in patients with advanced esophageal squamous cell carcinoma (CheckMate 648): 29-month follow-up from a randomized, open-label, phase III trial.

BACKGROUND: First-line nivolumab plus chemotherapy and nivolumab plus ipilimumab both demonstrated significant overall survival (OS) benefit versus chemotherapy in previously untreated patients with advanced esophageal squamous cell carcinoma (ESCC) in the CheckMate 648 trial, leading to approvals of both nivolumab-containing regimens in many countries. We report longer-term follow-up data. METHODS: This open-label, phase III trial (NCT03143153) enrolled adults with previously untreated, unresectable, advanced, recurrent, or metastatic ESCC. Patients were randomized 1:1:1 to nivolumab plus chemotherapy, nivolumab plus ipilimumab, or chemotherapy. Primary endpoints were OS and progression-free survival (PFS) by blinded independent central review. Hierarchical testing was performed first in patients with tumor cell programmed death ligand 1 (PD-L1) expression of ≥1% and then in the overall population. RESULTS: A total of 970 patients were randomly assigned. After 29 months of minimum follow-up, nivolumab plus chemotherapy continued to demonstrate improvement in OS versus chemotherapy (hazard ratio [HR] = 0.59 [95% CI: 0.46-0.76]) in patients with tumor cell PD-L1 expression of ≥1% and in the overall population (HR = 0.78 [95% CI: 0.65-0.93]) and with nivolumab plus ipilimumab versus chemotherapy (HR = 0.62 [95% CI: 0.48-0.80]) in patients with tumor cell PD-L1 expression of ≥1% and in the overall population (HR = 0.77 [95% CI: 0.65-0.92]). In patients with tumor cell PD-L1 expression of ≥1%, nivolumab plus chemotherapy demonstrated PFS benefit versus chemotherapy (HR = 0.67 [95% CI: 0.51-0.89]); PFS benefit was not observed with nivolumab plus ipilimumab versus chemotherapy (HR = 1.04 [95% CI: 0.79-1.36]). Among all treated patients (n = 936), Grade 3-4 treatment-related adverse events were reported in 151 (49%, nivolumab plus chemotherapy), 105 (32%, nivolumab plus ipilimumab), and 110 (36%, chemotherapy) patients. CONCLUSIONS: Nivolumab plus chemotherapy and nivolumab plus ipilimumab continued to demonstrate clinically meaningful OS benefit versus chemotherapy with no new safety signals identified with longer follow-up, further supporting use as first-line standard treatment options for patients with advanced ESCC.

Salvage surgery for pouch-related complication after ileal pouch-anal anastomosis: a report of two cases.

BACKGROUND: Pouch-related complications (PRCs), such as pelvic abscesses and perianal complex fistulas, can occur after ileal pouch-anal anastomosis (IPAA) in ulcerative colitis (UC). They are often difficult to treat and require salvage surgery. We report two cases of PRC associated with fistulas. CASE PRESENTATION: First case: A 38-year-old man was diagnosed with UC at age 26 years. Four months after the diagnosis of UC, the patient underwent hand-assisted laparoscopic restorative proctocolectomy, IPAA, and ileostomy for acute fulminant UC. Two years after the closure of the ileostomy, the patient developed a perianal abscess and underwent ileostomy reconstruction. He was referred to our department at 35 years of age, because his symptoms did not improve despite repeated seton drainage of a complicated perineal fistula. We diagnosed PRC with a pelvic abscess and complicated pouch fistula and performed salvage surgery. This diagnosis was revised to Crohn's disease. SECOND CASE: A 50-year-old man was diagnosed with UC at age 18 years and was administered high doses of steroids; however, his symptoms did not improve. He underwent restorative proctocolectomy, IPAA, and ileostomy at another hospital. The ileostomy was closed, and his condition stabilized thereafter. At 35 years of age, perianal pain developed, and he was diagnosed with a complicated pouch-perineal fistula. A fistula was observed near the staple line of the ileal end closure on the head side of the pouch. Reconstruction of the ileostomy and seton drainage were performed; however, his symptoms did not improve, and he was referred to our hospital. We diagnosed PRC with a pelvic abscess and a complicated pouch fistula and performed salvage surgery. The resected specimen showed strictures in two locations: at the oral site of the afferent limb (at the pouch) and at the IPAA. Both patients returned to society and are currently outpatients. CONCLUSIONS: We encountered two cases of PRC after IPAA that did not improve with seton drainage or ileostomy. Pouch resection was performed after considering the patient's quality of life and reintegration into society.

High-mobility group box 1 fragment ameliorates chronic pancreatitis induced by caerulein in mice.

BACKGROUND: Chronic pancreatitis (CP) is a progressive disease characterized by pancreatic fibrosis for which effective treatment options are lacking. Mesenchymal stem cells (MSCs) have shown potential for fibrosis treatment but face limitations in clinical application. The high-mobility group box 1 (HMGB1) fragment mobilizes MSCs from bone marrow into the blood and has emerged as a promising therapeutic agent for tissue regeneration in various pathological conditions. The aim of this study was to investigate the potential therapeutic effects of systemic administration of the HMGB1 fragment in a mouse model of CP. METHODS: A caerulein-induced CP mouse model was used, and the HMGB1 fragment was administered by tail vein injection. Parameters such as body weight, pancreatic tissue damage, fibrosis, inflammatory cytokine expression, and collagen-related gene expression were evaluated using various assays, including immunohistochemistry, real-time PCR, serum analysis, and single-cell transcriptome analysis. And the migration of MSCs to the pancreas was evaluated using the parabiosis model. RESULTS: Administration of the HMGB1 fragment was associated with significant improvements in pancreatic tissue damage and fibrosis. It suppressed the expression of inflammatory cytokines and activated platelet-derived growth factor receptor-α+ MSCs, leading to their accumulation in the pancreas. The HMGB1 fragment also shifted gene expression patterns associated with pancreatic fibrosis toward those of the normal pancreas. Systemic administration of the HMGB1 fragment demonstrated therapeutic efficacy in attenuating pancreatic tissue damage and fibrosis in a CP mouse model. CONCLUSION: These findings highlight the potential of the HMGB1 fragment as a therapeutic target for the treatment of CP.

Prognostic factors of conversion surgery for stage IV gastric cancer: A multi-institutional retrospective analysis.

Background: Conversion surgery (CS) is a highly anticipated strategy for stage IV advanced gastric cancer (AGC) with a good response to chemotherapy. However, prognostic factors limiting R0 resection remain unclear. In this multi-institutional study, we investigated the clinical outcomes of CS for stage IV AGC and the prognostic factors of CS-limiting R0 resection and analyzed them according to metastatic patterns. Methods: Clinical data on 210 patients who underwent CS for stage IV AGC at six institutions between 2007 and 2017 were retrospectively retrieved. The patient background, preoperative treatment, operative outcomes, and survival times were recorded. Prognostic factors for overall and recurrence-free survival were investigated using univariate and multivariate analyses for patients who underwent R0 resection. Results: R0 resection was achieved in 146 (70%) patients. The median survival time was 32 months, and the 3-year survival rate was 45%. Patients who achieved R0 resection had significantly longer survival than those with R1/2 resection (median survival time: 41.5 months vs. 20.7 months). Multivariate analysis identified pathological N positivity for overall and relapse-free survival and pathological T4 for relapse-free survival as significant independent poor prognostic factors of R0 resected patients. There was no significant difference in survival among the peritoneum, liver, and lymph node groups regarding the initial metastatic sites. Conclusions: CS with R0 resection for patients with stage IV AGC can lead to longer survival. Patients with pathological T4 and pathological N positivity were eligible for intensive adjuvant therapy after CS with R0 resection.