The metastatic pattern of intestinal and diffuse type gastric carcinoma - A Dutch national cohort study

Diffuse Gastric Cancer: A Comprehensive Review of Molecular Features and Emerging Therapeutics

Diffuse-type gastric cancer (DGC) accounts for approximately one-third of gastric cancer diagnoses but is a more clinically aggressive disease with peritoneal metastases and inferior survival compared with intestinal-type gastric cancer (IGC). The understanding of the pathogenesis of DGC has been relatively limited until recently. Multiomic studies, particularly by The Cancer Genome Atlas, have better characterized gastric adenocarcinoma into molecular subtypes. DGC has unique molecular features, including alterations in CDH1, RHOA, and CLDN18-ARHGAP26 fusions. Preclinical models of DGC characterized by these molecular alterations have generated insight into mechanisms of pathogenesis and signaling pathway abnormalities. The currently approved therapies for treatment of gastric cancer generally provide less clinical benefit in patients with DGC. Based on recent phase II/III clinical trials, there is excitement surrounding Claudin 18.2-based and FGFR2b-directed therapies, which capitalize on unique biomarkers that are enriched in the DGC populations. There are numerous therapies targeting Claudin 18.2 and FGFR2b in various stages of preclinical and clinical development. Additionally, there have been preclinical advancements in exploiting unique therapeutic vulnerabilities in several models of DGC through targeting of the focal adhesion kinase (FAK) and Hippo pathways. These preclinical and clinical advancements represent a promising future for the treatment of DGC.

Efficacy of neoadjuvant chemotherapy combined with prophylactic intraperitoneal hyperthermic chemotherapy for patients diagnosed with clinical T4 gastric cancer who underwent laparoscopic radical gastrectomy: a retrospective cohort study based on propensity score matching

BACKGROUND

Clinical T4 (cT4) stage gastric cancer presents with frequent postoperative recurrence and poor prognosis. This study is to evaluate the oncological efficacy of laparoscopic radical total gastrectomy combined with postoperative prophylactic hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with cT4N + M0 gastric cancer who received neoadjuvant chemotherapy.

METHODS

We reviewed the clinicopathological data of 174 patients with clinical T4 gastric cancer who underwent neoadjuvant chemotherapy followed by laparoscopic radical total gastrectomy between June 2017 and December 2021. Among them, 142 were included in the non-HIPEC group, and 32 in the HIPEC group. Patients in both groups were paired based on propensity score in a 2:1 ratio to assess disparities in tumor recurrence and long-term survival.

RESULTS

After matching, there were no significant differences in the clinicopathological data between the two groups. The peritoneum (16.1%) and distant organs (10.9%) were the most frequent locations for recurrence. Prior to matching, the recurrence rates were similar at all sites for both groups. Compared with those in the non-HIPEC cohort, the recurrence rates at all sites, the lung, and the peritoneum were notably lower in the HIPEC cohort. Prior to matching, the 3-year overall survival and disease-free survival rates were similar between the two groups; following matching, the HIPEC group exhibited notably greater survival rates than did the non-HIPEC group. The disparities in survival rates between the groups became even more pronounced after conducting a stratified analysis among patients with stage III disease.

CONCLUSIONS

Neoadjuvant chemotherapy combined with prophylactic HIPEC after laparoscopic radical gastrectomy can effectively reduce the rate of peritoneal metastasis in patients with cT4N + M0 advanced gastric cancer and significantly improve the prognosis of such patients, which is of great clinical value.

Short-Term Safety Evaluation of Albumin-Bound Paclitaxel in Intraoperative and Postoperative Hyperthermic Intraperitoneal Chemotherapy for Gastric Cancer

PURPOSE

To evaluate the short-term safety of albumin-bound paclitaxel in hyperthermic intraperitoneal chemotherapy (HIPEC) during and after gastric cancer (GC) surgery.

METHODS

A retrospective analysis of clinical data was conducted for GC surgery patients at Zhongnan Hospital of Wuhan University, from January 2020 to September 2022. The study group (n = 120) received HIPEC and the control group (n = 268) did not receive albumin-bound paclitaxel. Short-term safety indicators including intraoperative complications, hematological toxicity, liver and kidney function, and gastrointestinal function recovery were compared between the two groups.

RESULTS

There were no statistically significant differences between the two groups regarding intraoperative complications, hematological toxicity, liver and kidney function, and gastrointestinal function recovery time (P > 0.05 for all). In the study group, patients were further divided into subgroups based on dose and timing. Subgroup analysis revealed no significant differences among the different dose subgroups. However, when focusing on timing subgroups, the postoperative subgroup exhibited significantly higher white blood cell counts and bilirubin levels compared to the intraoperative subgroup, while the intraoperative subgroup had significantly higher bilirubin levels compared to both postoperative and intraoperative plus postoperative subgroups.

CONCLUSION

Albumin-bound paclitaxel demonstrates good safety and tolerability in HIPEC during and after GC surgery, without increasing the risk of intraoperative complications.

Liquid biopsy for gastric cancer: Techniques, applications, and future directions

After the study of circulating tumor cells in blood through liquid biopsy (LB), this technique has evolved to encompass the analysis of multiple materials originating from the tumor, such as nucleic acids, extracellular vesicles, tumor-educated platelets, and other metabolites. Additionally, research has extended to include the examination of samples other than blood or plasma, such as saliva, gastric juice, urine, or stool. LB techniques are diverse, intricate, and variable. They must be highly sensitive, and pre-analytical, patient, and tumor-related factors significantly influence the detection threshold, diagnostic method selection, and potential results. Consequently, the implementation of LB in clinical practice still faces several challenges. The potential applications of LB range from early cancer detection to guiding targeted therapy or immunotherapy in both early and advanced cancer cases, monitoring treatment response, early identification of relapses, or assessing patient risk. On the other hand, gastric cancer (GC) is a disease often diagnosed at advanced stages. Despite recent advances in molecular understanding, the currently available treatment options have not substantially improved the prognosis for many of these patients. The application of LB in GC could be highly valuable as a non-invasive method for early diagnosis and for enhancing the management and outcomes of these patients. In this comprehensive review, from a pathologist's perspective, we provide an overview of the main options available in LB, delve into the fundamental principles of the most studied techniques, explore the potential utility of LB application in the context of GC, and address the obstacles that need to be overcome in the future to make this innovative technique a game-changer in cancer diagnosis and treatment within clinical practice.

Peritoneal metastases from gastric cancer in a nationwide cohort: Incidence, treatment and survival

The aims of this study were to investigate incidence, risk factors and treatment of synchronous or metachronous peritoneal metastases (PM) from gastric cancer and to estimate survival of these patients using population-based data. Patients diagnosed with gastric cancer in 2015 to 2016 were selected from the Netherlands Cancer Registry. The incidence of synchronous and metachronous PM were calculated. Multivariable regression analyses were performed to identify factors associated with the occurrence of PM. Treatment and survival were compared between patients with synchronous and metachronous PM. Of 2206 patients with gastric cancer, 741 (34%) were diagnosed with PM. Of these, 498 (23%) had synchronous PM. The cumulative incidence of metachronous PM in patients who underwent potentially curative treatment (n = 675) was 22.8% at 3 years. A factor associated with synchronous and metachronous PM was diffuse type histology. Patients diagnosed with synchronous PM more often received systemic treatment than patients with metachronous PM (35% vs 18%, respectively, P < .001). Median overall survival was comparable between synchronous and metachronous PM (3.2 vs 2.3 months, respectively, P = .731). Approximately one third of all patients with gastric cancer are diagnosed with PM, either at primary diagnosis or during 3-year follow-up after potentially curative treatment. Patients with metachronous PM less often received systemic treatment than those with synchronous PM but survival was comparable between both groups. Future trials are warranted to detect gastric cancer at an earlier stage and to examine strategies that lower the risk of peritoneal dissemination. Also, specific treatment options for patients with gastric PM should be further investigated.

Outcomes after Surgical Treatment of Oesophagogastric Cancer with Synchronous Liver Metastases: A Multicentre Retrospective Cohort Study

Approximately 10-12% of patients with oesophageal or gastric cancer (OGC) present with oligometastatic disease at diagnosis. It remains unclear if there is a role for radical surgery in these patients. We aimed to assess the outcomes of OGC patients who underwent simultaneous treatment for the primary tumour and synchronous liver metastases. Patients with OGC who underwent surgical treatment between 2008 and 2020 for the primary tumour and up to five synchronous liver metastases aiming for complete tumour removal or ablation (i.e., no residual tumour) were identified from four institutional databases. The primary outcome was overall survival (OS), calculated with the Kaplan-Meier method. Secondary outcomes were disease-free survival and postoperative outcomes. Thirty-one patients were included, with complete follow-up data for 30 patients. Twenty-six patients (84%) received neoadjuvant therapy followed by response evaluation. Median OS was 21 months [IQR 9-36] with 2- and 5-year survival rates of 43% and 30%, respectively. While disease recurred in 80% of patients (20 of 25 patients) after radical resection, patients with a solitary liver metastasis had a median OS of 34 months. The number of liver metastases was a prognostic factor for OS (solitary metastasis aHR 0.330; p-value = 0.025). Thirty-day mortality was zero and complications occurred in 55% of patients. Long-term survival can be achieved in well-selected patients who undergo surgical resection of the primary tumour and local treatment of synchronous liver metastases. In particular, patients with a solitary liver metastasis seem to have a favourable prognosis.

Gastric Extent of Tumor Predicts Peritoneal Metastasis in Siewert II Adenocarcinoma

BACKGROUND

Whereas current guidelines recommend staging laparoscopy for most patients with potentially resectable gastric cancer, such a recommendation for patients with adenocarcinoma of the gastroesophageal junction (AEG) is lacking. This study sought to identify baseline clinicopathologic characteristics associated with peritoneal metastasis (PM) among patients with Siewert II AEG.

METHODS

Trimodality therapy-eligible patients with Siewert II AEG (2000-2015, single institution) were retrospectively identified. A composite PM outcome was defined as follows: (1) PM at staging laparoscopy; (2) PM diagnosed during neoadjuvant chemoradiation; or (3) PM ≤6 months postoperatively. Logistic regression was used to identify features associated with PM; bootstrapped analysis (Youden J) identified the distal tumor extension that best discriminated the composite outcome.

RESULTS

Of 188 patients, a composite PM outcome was observed in 26 of 188 (13.8%); 12 of 26 had positive staging laparoscopy, 10 of 26 experienced PM during chemoradiation, and 4 of 26 had PM ≤6 months postoperatively. Tumor extension below the GEJ was greater in patients with PM (median, 4.0 cm [interquartile range, 3.0-5.0] vs 3.0 cm [interquartile range, 2.0-3.0]; P < .001). All patients with PM had cT3 to cT4 tumors. Among patients with cT3 to cT4 tumors (n = 168 of 188; 89.4%), distal tumor extent (odds ratio, 1.67/cm; 95% CI, 1.23-2.28; P = .001) was independently associated with increased odds of PM. Gastric tumor extension ≥4 cm remained independently associated with PM (OR, 5.14; 95% CI, 2.11-12.53; P < .001) after adjustment for signet ring cell status.

CONCLUSIONS

Distal tumor extent beyond the GEJ is independently associated with increased odds of PM in patients with Siewert II AEG. Patients with extensive gastric involvement should therefore be considered for staging laparoscopy before trimodality therapy.

A population-based comparison of patients with metastatic esophagogastric carcinoma between Japan and the Netherlands

PURPOSE

Differences exist between Asian and Western patients with esophagogastric cancer, for example in terms of histological subtype and treatment strategies. This study aimed to compare characteristics and treatment between patients with metastatic esophagogastric cancer from Japan and the Netherlands using nationwide cancer registry data.

METHODS

Patients diagnosed with metastatic esophageal or gastric cancer were included from the nationwide national cancer registry of Japan (2016-2019) and the Netherlands (2015-2020). Treatment strategies were analyzed using chi-squared tests.

RESULTS

The proportion of patients with metastatic esophageal (16.0% vs 34.2%) and gastric cancer (14.9% vs 45.2%) were lower in Japan compared to the Netherlands. Japanese patients with metastatic esophageal adenocarcinoma (EAC), esophageal squamous cell carcinoma (ESCC) or gastric cancer (GC) were more often male and older compared to Dutch patients. Proportion of patients with metastatic disease who received surgical resection was higher in Japan compared to the Netherlands (EAC 9.3 vs 1.4%, p < 0.001; ESCC 10.7% vs 2.3%, p < 0.001; GC 12.0% vs 3.6% p < 0.001). Proportion of patients who received systemic therapy was also higher (EAC 44.8% vs 30.4%, p < 0.001; ESCC 26.6% vs 12.0%, p < 0.001; GC 50.7% vs 35.8% p < 0.001).

CONCLUSIONS

Japanese patients less often presented with metastatic esophagogastric cancer and more often underwent surgical resection or received systemic therapy compared to Dutch patients. Further investigation should elucidate what the deliberations are in both Japan and the Netherlands and if more patients in the Netherlands could benefit from surgical resection or systemic therapy and whether this would translate in better survival and quality of life.

Regional Immunotherapy for Peritoneal Carcinomatosis in Gastroesophageal Cancer: Emerging Strategies to Re-Condition a Maladaptive Tumor Environment

Peritoneal carcinomatosis originating from gastric/gastroesophageal junction cancer (GC-PC) occurs in a defined subset of gastric cancer patients with unique clinical, pathologic, molecular and immunologic characteristics that create significant obstacles to effective treatment with modern therapy. Although systemic chemo- and immuno- therapy have yielded disappointing results in GC-PC, recent advances in the characterization of GC-PC and peritoneal immune biology present new opportunities for targeted therapeutics. In this review article, we discuss the distinct properties of GC-PC and the peritoneal immune environment as they pertain to current and investigative treatment strategies. We discuss pre-clinical studies and clinical trials relevant to the modulation of the peritoneal environment as a therapeutic intervention in GC-PC. Finally, we present a road map for future combinatorial strategies based on the conception of the peritoneal cavity as a bioreactor. Within this isolated compartment, prevailing immunosuppressive conditions can be altered through regional interventions toward an adaptive phenotype that would support the effectiveness of regionally delivered cellular therapy products. It is hoped that novel combination strategies would promote efficacy not only in the sequestered peritoneal environment, but also via migration into the circulation of tumor-reactive lymphocytes to produce durable systemic disease control, thereby improving oncologic outcome and quality of life in patients with GC-PC.

Sleep Duration and Stress Level in the Risk of Gastric Cancer: A Pooled Analysis of Case-Control Studies in the Stomach Cancer Pooling (StoP) Project

The association between sleep and stress and cancer is underinvestigated. We evaluated these factors in association with gastric cancer (GC). Five case-control studies from the Stomach Cancer Pooling (StoP) Project were included. We calculated the odds ratios (ORs) and the corresponding 95% confidence intervals (CIs) for sleep duration and stress level in association with GC through multiple logistic regression models adjusted for several lifestyle factors. The analysis included 1293 cases and 4439 controls, 215 cardia and 919 noncardia GC, and 353 diffuse and 619 intestinal types. Sleep duration of ≥9 h was associated with GC (OR =1.57, 95% CI = 1.23-2.00) compared to 8 h. This was confirmed when stratifying by subsite (noncardia OR = 1.59, 95% CI = 1.22-2.08, and cardia OR = 1.63, 95% CI = 0.97-2.72) and histological type (diffuse OR = 1.65, 95% CI = 1.14-2.40 and intestinal OR = 1.24, 95% CI = 0.91-1.67). Stress was associated with GC (OR = 1.33, 95% CI = 1.18-1.50, continuous). This relationship was selectively related to noncardia GC (OR = 1.28, 95% 1.12-1.46, continuous). The risk of diffuse (OR = 1.32, 95% CI = 1.11-1.58) and intestinal type (OR = 1.23, 95% CI = 1.07-1.42) were higher when stress was reported. Results for the association between increasing level of stress and GC were heterogeneous by smoking and socioeconomic status (p for heterogeneity = 0.02 and <0.001, respectively). In conclusion, long sleep duration (≥9 h) was associated with GC and its subtype categories. Stress linearly increased the risk of GC and was related to noncardia GC.

Incidence, Stage, Treatment, and Survival of Noncardia Gastric Cancer

Importance

Gastric cancer is the fifth most common cancer worldwide, and investigating its incidence, characteristics, treatment, and outcomes over the past decades can help in selecting clinical strategies and future research directions.

Objective

To analyze the trends in incidence, staging, and treatment of gastric cancer.

Design, Setting, and Participants

This nationwide, population-based cohort study included patients diagnosed with noncardia gastric cancer (NCGC) between 1989 and 2021 in the Netherlands.

Main Outcomes and Measures

Differences in tumor characteristics, treatment, and survival were analyzed per fixed time periods (1989-1993, 1994-1998, 1999-2003, 2004-2008, 2009-2013, 2014-2018, and 2019-2021).

Results

In total, 47 014 patients (median [IQR] age, 73 [64-80] years; 28 032 [60%] male patients) were identified with mostly adenocarcinomas of the antrum region (when location was known). Age-standardized incidence decreased from 20.3 to 6.1 per 100 000 person-years between 1989 and 2021. During the study period, unknown T and N stages were recorded less frequently, and metastatic disease was diagnosed more frequently (1989-1993: 2633 of 9493 patients [28%]; 2019-2021: 1503 of 3200 patients [47%] in 2019-2021). Over time, fewer patients with metastatic disease underwent surgery with or without other treatment modalities (68% in 1989-1993 vs 64% in 2019-2021), and palliative chemotherapy in metastatic NCGC increased from 9% to 40%. For patients with nonmetastatic disease, 5-year relative survival improved from 28% (95% CI, 26.5%-29.2%) to 36% (95% CI, 33.5%-37.6%) between 1989 and 2021. For patients with nonmetastatic disease undergoing a resection, 5-year survival increased from 40% (95% CI, 38.3%-41.8%) to 51% (95% CI, 47.9%-53.3%). For patients with metastatic disease, 1-year relative survival increased from 10% (95% CI, 8.7%-11.1%) to 19% (95% CI, 17.2%-21.6%), but 3-year relative survival remained poor at 5% (95% CI, 3.6%-7.5%).

Conclusions and Relevance

In this nationwide cohort study involving 47 014 patients diagnosed with NCGC (1989-2021), the results showed a decrease in incidence, more accurate staging, a shift in treatment modalities, and improved patient survival.

Insights into synchronous peritoneal metastases from hepatobiliary origin: Incidence, risk factors, treatment, and survival from a nationwide database

INTRODUCTION

- This population-based study aimed to investigate incidence, risk factors, treatment, and survival of synchronous peritoneal metastases (PM) of hepatobiliary origin.

METHODS

- All Dutch patients diagnosed with hepatobiliary cancer between 2009 and 2018 were selected. Factors associated with PM were identified with logistic regression analyses. Treatments for patients with PM were categorized into local therapy, systemic therapy, and best supportive care (BSC). Overall survival (OS) was investigated using log-rank test.

RESULTS

- In total, 12 649 patients were diagnosed with hepatobiliary cancer of whom 8% (n = 1066) were diagnosed with synchronous PM (12% [n = 882/6519] in biliary tract cancer [BTC] vs. 4% [n = 184/5248] in hepatocellular carcinoma [HCC]). Factors that were positively associated with PM were the female sex (OR 1.18, 95% CI 1.03-1.35), BTC (OR 2.93, 95% CI 2.46-3.50), diagnosis in more recent years (2013-2015: OR 1.42, 95% CI 1.20-1.68; 2016-2018: OR 1.48, 95% CI 1.26-1.75), T3/T4 stage (OR 1.84, 95% CI 1.55-2.18), N1/N2 stage (OR 1.31, 95% CI 1.12-1.53) and other synchronous systemic metastases (OR 1.85, 95% CI 1.62-2.12). Of all PM patients, 723 (68%) received BSC only. Median OS was 2.7 months (IQR 0.9-8.2) in PM patients.

CONCLUSION

- Synchronous PM were found in 8% of all hepatobiliary cancer patients and occurred more often in BTC than in HCC. Most patients with PM received BSC only. Given the high incidence and dismal prognosis of PM patients, extended research in hepatobiliary PM is needed to achieve better outcome in these patients.

Exploratory Analysis of Patients With Gastric/Gastroesophageal Junction Adenocarcinoma With or Without Liver Metastasis From the Phase 3 RAINBOW Study

PURPOSE

Liver metastasis (LM) is reported in approximately 40% of patients with advanced/metastatic gastric/gastroesophageal junction adenocarcinoma (metastatic esophagogastric adenocarcinoma; mGEA) and is associated with a worse prognosis. This post-hoc analysis from the RAINBOW trial reported the efficacy, safety, and biomarker outcomes of ramucirumab and paclitaxel combination treatment (RAM+PAC) in patients with (LM+) and without (LM-) LM at baseline.

MATERIALS AND METHODS

Patients (n=665) were randomly assigned on a 1:1 basis to receive either RAM+PAC (LM+: 150, LM-: 180) or placebo and paclitaxel (PL+PAC) (LM+: 138, LM-: 197). The overall survival (OS) and progression-free survival (PFS) were evaluated using stratified Kaplan-Meier and Cox regression models. The correlation of dichotomized biomarkers (VEGF-C, D; VEGFR-1,2) with efficacy in the LM+ versus LM- subgroups was analyzed using the Cox regression model with reported interaction P-values.

RESULTS

The presence of LM was associated with earlier progression than those without LM, particularly in patients receiving PL+PAC (hazard ratio [HR], 1.68). RAM+PAC treatment improved OS and PFS irrespective of LM status but showed greater improvement in LM+ than that in LM- (OS HR, 0.71 [LM+] vs. 0.88 [LM-]; PFS HR, 0.47 [LM+] vs. 0.76 [LM-]). Treatment-emergent adverse events were similar between patients with and without LM. No predictive relationship was observed between biomarker levels (VEGF-C, D; VEGFR-1,2) and efficacy outcome (OS, PFS) (all interaction P-values >0.05).

CONCLUSIONS

RAM provided a significant benefit, irrespective of LM status; however, its effect was numerically stronger in patients with LM. Therefore, RAM+PAC is a clinically meaningful therapeutic option for patients with mGEA and LM.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01170663.

Effect of multimodal chemotherapy on survival of gastric cancer with liver metastasis – a population based analysis

Objectives

Limited efforts have been made to evaluate the effect of multimodal chemotherapy on the survival of gastric cancer patients with liver metastases (LMGC). This study aimed to identify prognostic factors in LMGC patients and the superiority of multimodal chemotherapy with respect to overall survival (OS) in these patients.

Methods

We conducted a retrospective cohort study of 1298 patients with M1 stage disease between January 2012 and December 2020. The effects of clinicopathological variables and preoperative chemotherapy (PECT), postoperative chemotherapy (POCT), and palliative chemotherapy on survival in patients with liver metastases (LM group) and non-liver metastases (non-LM group) were compared.

Results

Of the 1298 patients analysed, 546 (42.06%) were in the LM group and 752 (57.94%) were in the non-LM group. The median (interquartile range) age was 60 (51–66) years. The 1-year, 3-year and 5-year overall survival (OS) rates in the LM group were 29.3%, 13.9%, and 9.2%, respectively, and those in the non-LM group were. 38.2%, 17.4%, and 10.0%, respectively (P &lt; 0.05, &gt; 0.05, and &gt; 0.05, respectively.) The Cox proportional hazards model revealed that palliative chemotherapy was a significant independent prognostic factor in both the LM and non-LM groups. Age ≥55 years, N stage, and Lauren classification were also independent predictors of OS in the LM group (P &lt; 0.05). Palliative chemotherapy and POCT were associated with improved OS compared with PECT in the LM group (26.3% vs. 36.4% vs. 25.0%, P &lt; 0.001).

Conclusion

LMGC patients had a worse prognosis than non- LMGC. Number of metastatic sites more than 1, liver and other metastatic sites, no CT treatment and HER2-negative had a poor prognosis. LMGC patient may benefit more from palliative chemotherapy and POCT than from PECT. Further well-designed, prospective studies are needed to validate these findings.

The molecular biology of peritoneal metastatic disease

Peritoneal metastases are a common form of tumor cell dissemination in gastrointestinal malignancies. Peritoneal metastatic disease (PMD) is associated with severe morbidity and resistance to currently employed therapies. Given the distinct route of dissemination compared with distant organ metastases, and the unique microenvironment of the peritoneal cavity, specific tumor cell characteristics are needed for the development of PMD. In this review, we provide an overview of the known histopathological, genomic, and transcriptomic features of PMD. We find that cancers representing the mesenchymal subtype are strongly associated with PMD in various malignancies. Furthermore, we discuss the peritoneal niche in which the metastatic cancer cells reside, including the critical role of the peritoneal immune system. Altogether, we show that PMD should be regarded as a distinct disease entity, that requires tailored treatment strategies.

Liver oligometastatic disease in synchronous metastatic gastric cancer patients: a nationwide population-based cohort study

INTRODUCTION

This population-based cohort study analysed treatment, overall survival (OS), and independent prognostic factors for OS in gastric cancer patients with liver metastases.

METHODS

Between 2015 and 2017, patients with synchronous metastatic gastric or gastroesophageal junction adenocarcinoma limited to the liver were included from the prospectively maintained population-based Netherlands Cancer Registry. Liver oligometastatic disease (OMD) was defined as ≤3 liver metastases. The primary outcome was OS. Independent prognostic factors for OS were analysed using multivariable Cox regression analysis.

RESULTS

A total 295 patients with metastases limited to the liver were included. The primary tumour was resected in four patients (1.4%). Treatment for liver metastases consisted of chemotherapy alone (28.1%), trastuzumab plus chemotherapy (4.7%), surgery (1.0%), or best supportive care (67.5%). Median OS across all included patients was 4.0 months (95% confidence interval [CI]: 3.1-4.5). Liver OMD was detected in 77 patients (26%). Treatment for liver OMD consisted of chemotherapy alone (24.6%), trastuzumab plus chemotherapy (5.2%), surgery (3.9%), or best supportive care (67.5%). Median OS among patients with liver OMD was 5.7 months (95% CI: 4.8-7.5). Across all patients, better OS was independently associated with liver OMD (hazard ratio [HR] 0.66, 95% CI: 0.50-0.87), trastuzumab (HR 0.41, 95% CI: 0.23-0.72) but not with triplet compared with doublet chemotherapy (HR 0.94, 95% CI: 0.57-2.87). Worse OS was independently associated with unknown nodal stage versus cN0 (HR 1.74, 95% CI: 1.17-2.60), diffuse-type versus intestinal-type adenocarcinoma (HR 2.06, 95% CI: 1.32-3.20), and monotherapy or best supportive care versus doublet chemotherapy (HR 1.72, 95% CI: 1.03-2.87, and HR 3.61, 95% CI: 2.55-5.10, respectively).

CONCLUSION

In this population-based cohort study, liver OMD was detected in 26% of patients. Liver OMD and trastuzumab treatment were independently associated with better OS while triplet as compared with doublet chemotherapy was not. OS among patients with liver OMD nevertheless remained poor. The concept of OMD and the benefit of resection of liver OMD may still have been relatively unknown in this disease type during the study inclusion years.

Stereotactic radiotherapy or metastasectomy for oligometastatic esophagogastric cancer: a nationwide population-based cohort study

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This nationwide study included patients with esophagogastric cancer and OMD.

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Local treatment of OMD was associated with improved OS.

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Local treatment of OMD plus systemic therapy was associated with better OS.

•

Randomized trials are warranted to conform results.

Background and purpose

This nationwide population-based study analyzed the outcomes of local treatment (i.e. stereotactic body radiotherapy [SBRT] or metastasectomy) or systemic therapy for oligometastatic disease (OMD) in patients with esophagogastric cancer in The Netherlands.

Materials and methods

Between 2015 and 2016, all patients in The Netherlands with esophagogastric cancer and synchronous or metachronous OMD were eligible for inclusion. Patients who underwent local treatment of OMD (SBRT or metastasectomy) and/or systemic therapy were included. OMD was defined as distant metastases in 1 organ or 1 extra-regional lymph node region. The primary outcomes were overall survival (OS) and independent prognostic factors for OS. OS was calculated from diagnosis of OMD. Prognostic factors for OS were analyzed using a multivariable Cox proportional hazard model.

Results

A total of 594 patients were included, of whom 83 underwent local treatment for OMD alone, 22 local treatment plus systemic therapy, and 489 systemic therapy alone. Median OS after local treatment for OMD alone was 16.0 months, local treatment plus systemic therapy 22.7 months, and after systemic therapy alone 8.5 months. Improved OS was independently associated with local treatment for OMD alone or combined with systemic therapy as compared with systemic therapy alone (hazard ratio [HR] 0.52, 95% CI: 0.31–0.90 and HR 0.42, 95% CI: 0.22-0.82, respectively) and a controlled primary tumor(HR 0.48, 95% CI: 0.27–0.86). Worse OS was independently associated with worse performance scores (HR 1.41, 95%: 1.32-1.75), poorly or undiffertumor as compared with good or moderadifferentiated tumor (HR 1.37, 95% CI: 1.06-1.76), and peritoneal as compared with lymph mode metastases (HR 1.39, 95% CI: 1.00-1.93).

Conclusion

Local treatment of OMD alone or combined with systemic therapy was independently associated with improved OS as compared with systemic therapy alone in this population-based cohort study in The Netherlands. Randomized controlled trials are warranted to confirm these results.

PHLPP1 Overexpression was Associated With a Good Prognosis With Decreased AKT Activity in Gastric Cancer

Introduction: The aim of this study was to perform a clinicopathologic analysis of PHLPP1 expression in gastric cancer patients and analyze AKT activity with chemotherapy drug treatment in cancer subtypes. Materials and Methods: Surgically resected gastric cancer tissue specimens were obtained from 309 patients who underwent gastrectomy, and PHLPP1 expression was validated by tissue microarray analysis with immunohistochemistry. We assessed whether PHLPP1 selectively dephosphorylates Ser473 of AKT in an in-vitro study. Results: We found that the PHLPP1 overexpression (OE) group showed significantly greater proportions of differentiated subtype samples and early T stage samples, lower lymph node metastasis, and lower TNM stage than the PHLPP1 underexpression (UE) group. The overall survival of the PHLPP1-OE group was significantly higher (53.39 ± 0.96 months) than that of the PHLPP1-UE group (47.82 ± 2.57 months) (P = .01). In vitro analysis, we found that the PHLPP1-OE group showed a significant decrease in relative AKT S-473 levels in both cell lines (MKN-74 and KATO-III). We found that treatment with chemotherapy drugs decreased the activity of Ser473 in the MKN-74 cell line with PHLPP1 OE, but it did not affect the activity of Ser473 in KATO-III cells. Conclusion: We found that patients who overexpressed PHLPP1 showed low recurrence and good prognosis. PHLPP1 was found to work by lowering the activity of AKT Ser473 in gastric cancer. Additionally, we found a clue regarding the mechanism of chemotherapeutic drug resistance in a cell line of signet ring cell origin and will uncover this mechanism in the future.

18F-Fludeoxyglucose-Positron Emission Tomography/Computed Tomography and Laparoscopy for Staging of Locally Advanced Gastric Cancer: A Multicenter Prospective Dutch Cohort Study (PLASTIC)

Importance

The optimal staging for gastric cancer remains a matter of debate.

Objective

To evaluate the value of 18F-fludeoxyglucose-positron emission tomography with computed tomography (FDG-PET/CT) and staging laparoscopy (SL) in addition to initial staging by means of gastroscopy and CT in patients with locally advanced gastric cancer.

Design, Setting, and Participants

This multicenter prospective, observational cohort study included 394 patients with locally advanced, clinically curable gastric adenocarcinoma (≥cT3 and/or N+, M0 category based on CT) between August 1, 2017, and February 1, 2020.

Exposures

All patients underwent an FDG-PET/CT and/or SL in addition to initial staging.

Main Outcomes and Measures

The primary outcome was the number of patients in whom the intent of treatment changed based on the results of these 2 investigations. Secondary outcomes included diagnostic performance, number of incidental findings on FDG-PET/CT, morbidity and mortality after SL, and diagnostic delay.

Results

Of the 394 patients included, 256 (65%) were men and mean (SD) age was 67.6 (10.7) years. A total of 382 patients underwent FDG-PET/CT and 357 underwent SL. Treatment intent changed from curative to palliative in 65 patients (16%) based on the additional FDG-PET/CT and SL findings. FDG-PET/CT detected distant metastases in 12 patients (3%), and SL detected peritoneal or locally nonresectable disease in 73 patients (19%), with an overlap of 7 patients (2%). FDG-PET/CT had a sensitivity of 33% (95% CI, 17%-53%) and specificity of 97% (95% CI, 94%-99%) in detecting distant metastases. Secondary findings on FDG/PET were found in 83 of 382 patients (22%), which led to additional examinations in 65 of 394 patients (16%). Staging laparoscopy resulted in a complication requiring reintervention in 3 patients (0.8%) without postoperative mortality. The mean (SD) diagnostic delay was 19 (14) days.

Conclusions and Relevance

This study's findings suggest an apparently limited additional value of FDG-PET/CT; however, SL added considerably to the staging process of locally advanced gastric cancer by detection of peritoneal and nonresectable disease. Therefore, it may be useful to include SL in guidelines for staging advanced gastric cancer, but not FDG-PET/CT.

The Burden of Peritoneal Metastases from Gastric Cancer: A Systematic Review on the Incidence, Risk Factors and Survival

The peritoneum is a common metastatic site in gastric cancer. This systematic review provides an overview of the incidence, risk factors and survival of synchronous peritoneal metastases from gastric cancer. A systematic search was performed to identify studies wherein the incidence, risk factors and survival of gastric cancer with peritoneal metastases were investigated. Of all 38 potentially eligible studies, 17 studies were included based on the eligibility criteria. The incidence of synchronous gastric peritoneal metastases was reviewed for population-based studies (10–21%), for observational cohort studies (2–15%) and for surgical cohort studies (13–40%). Potential risk factors for synchronous gastric peritoneal metastases were younger age, non-cardia gastric cancer, female sex, signet ring cell carcinoma, diffuse type histology or linitis plastica, T4 stage, Hispanic ethnicity and more than one metastatic location. Synchronous peritoneal metastases are commonly diagnosed in patients with gastric cancer with an incidence up to 21% in recent population-based studies. Furthermore, prognosis of patients with gastric peritoneal metastases is poor with median overall survival ranging from 2 to 9 months. The high incidence and poor prognosis require intensive research on diagnostic features and effective treatment options to improve survival.

Risk Factors for Metachronous Isolated Peritoneal Metastasis after Preoperative Chemotherapy and Potentially Curative Gastric Cancer Resection: Results from the CRITICS Trial

Simple Summary

Around 20% of gastric cancer patients develop peritoneal metastasis after preoperative chemotherapy and curative surgery. Patients with peritoneal metastasis as a single site of metastasis may potentially benefit from prophylactic strategies. In this post-hoc analysis of the international phase III CRITICS trial, we aim to identify factors that can distinguish patients at high risk for developing peritoneal metastasis as a single site. Diffuse or mixed histological subtype, tumors with serosal involvement (ypT4) and advanced lymph node stage (ypN3 or a tumor positive lymph node ratio >20%) were independent risk factors for isolated peritoneal metastasis after preoperative chemotherapy and curative surgery. The combination of these risk factors identifies a subgroup that may benefit from treatment strategies that aim to prevent peritoneal metastasis.

Abstract

Gastric cancer (GC) patients at high risk of developing peritoneal metastasis (PM) as a single site of metastasis after curative treatment may be candidates for adjuvant prophylactic strategies. Here we investigated risk factors for metachronous isolated PM in patients who were treated in the CRITICS trial (NCT00407186). Univariable and multivariable analyses on both metachronous isolated PM and ‘other events’, i.e., (concurrent) distant metastasis, locoregional recurrence or death, were performed using a competing risk model and summarized by cumulative incidences. Isolated PM occurred in 64 of the 606 (11%) included patients. Diffuse or mixed histological subtype, ypT4 tumor stage and LN^high (ypN3 lymph node stage or a lymph node ratio >20%) were independent risk factors for isolated PM in both univariable and multivariable analyses. Likewise, LN^high was an independent risk factor for ‘other events’. Patients with tumors who were positive for all three independent risk factors had the highest two-year cumulative incidence of 43% for isolated PM development. In conclusion, diffuse or mixed histological subtype, ypT4 and LN^high were identified as independent risk factors for isolated PM in patients treated with preoperative chemotherapy followed by surgical resection. The combination of these factors may identify a subgroup that may benefit from PM-preventing treatment strategies.