Prognosis of poorly cohesive gastric cancer after complete cytoreductive surgery with or without hyperthermic intraperitoneal chemotherapy (CYTO-CHIP study)

Treatment of Gastric Cancer Carcinomatosis

Patients with gastric cancer peritoneal metastases (GCPM) have Stage IV disease. Systemic therapy is a crucial aspect of their care. Patients with GCPM should have their tumors tested for HER2 and PD-L1 expression and microsatellite instability for potential targeted therapies. If patients with synchronous GCPM have stable disease following neoadjuvant therapy, surgical intervention can be considered. Patients with positive cytology or low-volume peritoneal disease (peritoneal carcinomatosis index [PCI] < 7) may "convert" to negative cytology or resolution of peritoneal metastases following intraperitoneal therapy and may be candidates for subsequent gastrectomy.

Emerging Trends in the Management of Gastric Malignancy with Peritoneal Dissemination: Same Disease, Heterogeneous Prognosis

Gastric cancer is a significant global contributor to cancer-related mortality. Stage IV gastric cancer represents a significant percentage of patients in Western countries, with peritoneal dissemination being the most prevalent site. Peritoneal disease comprises two distinct entities, macroscopic (P1) and microscopic (P0CY1), which are associated with poor long-term survival rates. Although the present standard of treatment is palliative chemotherapy, a global controversy has arisen concerning specific patients with limited disease burden or conversion to negative lavage cytology following chemotherapy. Available approaches include systemic or intraperitoneal chemotherapy, upfront gastrectomy, and conversion surgery. This review consolidated the current evidence regarding multimodal management, indicating prolonged survival for this distinct subgroup of patients. Considering the complexity of peritoneal metastases, the potential of the multimodal approach unveils promising prospects for identifying the optimal treatment for this particular subset of stage IV patients and thus enhancing their survival outcomes.

HIPEC for metastatic gastric cancer: Moving the needle towards 3-year survival

INTRODUCTION

Prior work has established hyperthermic intraperitoneal chemotherapy (HIPEC) administration as a safe treatment option for select patients with gastric adenocarcinoma and carcinomatosis. However, identifying patients who will maximally benefit from HIPEC remains unclear. This study assessed a single-institution experience with HIPEC for metastatic gastric cancer to identify variables associated with improved survival.

METHODS

A database of patients treated for metastatic gastric adenocarcinoma at MD Anderson Cancer Center from 2013 to 2022 was queried for patients undergoing HIPEC as part of their treatment regimen. Patients were stratified by overall survival (OS)≥36 months or <36 months and assessed along demographic and clinicopathologic variables to identify factors associated with OS ≥ 36 months.

RESULTS

Among 104 patients, 1,2, and 3-year OS from diagnosis was 89 %,44 %, and 18 %. Patients with OS ≥ 36 months were more likely to have moderately differentiated tumors, positive cytology only (i.e. no visible carcinomatosis), and lower peritoneal cancer index (PCI) than those with OS < 36 months (p = 0.002, p = 0.01, p = 0.001,respectively). Groups did not otherwise differ with respect to demographic parameters or treatment or pathologic details. Among patients who underwent gastrectomy, those with OS < 36 months had higher pathologic T and N category (p = 0.003 and p = 0.02, respectively). Postoperative mortality was zero in both groups among patients undergoing gastrectomy.

CONCLUSIONS

HIPEC may provide more durable survival benefit among patients with metastatic gastric cancer with moderately differentiated disease, low PCI, and positive cytology alone. Additionally, among patients who undergo gastrectomy, higher final pathologic T and N category are associated with worse survival. Trials are needed to compare 3-year OS rates in patients treated with HIPEC versus systemic therapy alone.

Survival Outcomes of Cytoreductive Surgery with HIPEC in Gastric Adenocarcinoma: A National Cancer Database Study

BACKGROUND

This study aimed to assess the impact of cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) on the survival outcomes for patients with gastric cancer and peritoneal carcinomatosis (PC).

METHODS

A retrospective analysis of the National Cancer Database from 2004 to 2020 identified patients with topography and histology codes consistent with gastric adenocarcinoma who underwent CRS/HIPEC. The exclusion criteria ruled out known other distant metastasis and missing key data. The study compared the CRS/HIPEC group with patients who had stage IV disease (with the same exclusions for distant metastases) and received systemic chemotherapy but no surgery to the primary site.

RESULTS

The study included 148 patients who underwent CRS/HIPEC. Their median age was 57 years (interquartile range [IQR], 47-66 years), with 57.4% of the patients identifying as male and 73.6% identifying as white. Most of the CRS/HIPEC patients had locally advanced disease, with 33.8% having pT4 disease and 23% patients having pN3 status. The Charlson-Deyo scores were 0 for 77% and 1 for 16.9% of the patients. The overall survival (OS) among the stage IV patients managed with CRS/HIPEC was significantly longer than for the patients receiving only systemic chemotherapy (median survival, 18.1 vs 9.3 months; p < 0.001), and the 1-year OS was 72.6% versus 38.8% (p < 0.05)). Among the stage IV patients, CRS/HIPEC showed better survival than systemic chemotherapy (hazard ratio [HR], 0.57; 95% confidence interval [CI], 0.44-0.73; p < .001) when control was used for the Charlson Deyo score, histology, age, and sex.

CONCLUSIONS

These results suggest the association of CRS/HIPEC with improved survival for selected patients with gastric adenocarcinoma and peritoneal disease. Some of this difference may have been due to selection bias, but the differences in the survival curves are robust.

Conversion surgery for gastric cancer with PM

It remains unclear whether the application of surgery to gastric cancer with peritoneal carcinomatosis prolongs survival. Twenty studies on conversion surgery were reviewed. Key points were the response to chemotherapy, complete resection, and a low tumor burden at the time of surgery. A bidirectional approach has been developed to increase the response rate. There are two different strategies in surgery. The outcomes of ongoing trials may clarify controversial issues.

Gastric Cancer: An Up-to-Date Review with New Insights into Early-Onset Gastric Cancer

Gastric cancer (GC) is the fifth most frequently diagnosed cancer and the fifth most common cause of cancer death in the world. Regarding the age at which the diagnosis was made, GC is divided into early-onset gastric cancer (EOGC-up to 45 years of age) and conventional GC (older than 45). EOGC constitutes approximately 10% of all GCs. Numerous reports indicate that EOGC is more aggressive than conventional GC and is often discovered at an advanced tumor stage, which has an impact on the five-year survival rate. The median survival rate for advanced-stage GC is very poor, amounting to less than 12 months. Risk factors for GC include family history, alcohol consumption, smoking, Helicobacter pylori, and Epstein-Barr virus infection. It has been shown that a proper diet and lifestyle can play a preventive role in GC. However, research indicates that risk factors for conventional GC are less correlated with EOGC. In addition, the unclear etiology of EOGC and the late diagnosis of this disease limit the possibilities of effective treatment. Genetic factors are considered a likely cause of EOGC, as young patients are less exposed to environmental carcinogens. Research characterizing GC in young patients is scarce. This comprehensive study presents all aspects: epidemiology, risk factors, new treatment strategies, and future directions.

Important Predictive Factors for the Prognosis of Patients With Peritoneal Metastasis of Gastric Cancer

BACKGROUND

This study investigated predictive factors for patients with peritoneal metastases of gastric cancer (PMGC) who underwent conversion cytoreductive surgery (C-CRS) and hyperthermic intraperitoneal intraoperative chemotherapy (HIPEC) after responding to induction chemotherapy (laparoscopic HIPEC [LHIPEC]) followed by concomitant systemic and intraperitoneal chemotherapy (bidirectional intraperitoneal and systemic chemotherapy [BIC]).

METHODS

Diagnostic laparoscopy was performed for 62 patients with PMGC between January 2017 and December 2022. The patients underwent LHIPEC and BIC induction chemotherapy using intraperitoneal docetaxel (30 mg/m2) and cisplatin (30 mg/m2), and intravenous chemotherapy for three cycles. The predictive parameters for progression-free and overall survival were analyzed using Kaplan-Meier and Cox regression analyses. The optimal cutoff values for Ki-67 parameters were assessed using receiver operating characteristic curve analysis.

RESULTS

The study retrospectively examined 36 (58 %) of 62 patients who responded to induction therapy and underwent C-CRS or HIPEC. A Ki-67 index lower than 10 (p = 0.000), lymph node involvement (LNI) less than 2 (p = 0.039), and an omental lesion size score lower than 0.5 cm (p = 0.002) were predictive of recurrence-free and overall survival in addition to completeness of cytoreduction and the peritoneal cancer index. Cox regression analysis showed that the independent factors associated with recurrence-free survival were decreased Ki-67 expression (≥10 % vs <10 %) (hazard ratio [HR] 4.7; 95 % confidence interval [CI] 1.6-5.210; p = 0.020) and LNI higher than 2 (HR 1.92; 95% CIS 0.923-4.0; p = 0.023).

CONCLUSIONS

Lymph node involvement and decreased Ki-67 expression are independent predictive factors of recurrence-free survival for patients with PMGC after induction chemotherapy.

Pan-Asian adapted ESMO Clinical Practice Guidelines for the diagnosis, treatment and follow-up of patients with gastric cancer

The European Society for Medical Oncology (ESMO) Clinical Practice Guidelines for the diagnosis, treatment and follow-up of patients with gastric cancer (GC), published in late 2022 and the updated ESMO Gastric Cancer Living Guideline published in July 2023, were adapted in August 2023, according to previously established standard methodology, to produce the Pan-Asian adapted (PAGA) ESMO consensus guidelines for the management of Asian patients with GC. The adapted guidelines presented in this manuscript represent the consensus opinions reached by a panel of Asian experts in the treatment of patients with GC representing the oncological societies of China (CSCO), Indonesia (ISHMO), India (ISMPO), Japan (JSMO), Korea (KSMO), Malaysia (MOS), the Philippines (PSMO), Singapore (SSO), Taiwan (TOS) and Thailand (TSCO), coordinated by ESMO and the Japanese Society of Medical Oncology (JSMO). The voting was based on scientific evidence and was independent of the current treatment practices, drug access restrictions and reimbursement decisions in the different Asian regions represented by the 10 oncological societies. The latter are discussed separately in the manuscript. The aim is to provide guidance for the optimisation and harmonisation of the management of patients with GC across the different regions of Asia, drawing on the evidence provided by both Western and Asian trials, whilst respecting the differences in screening practices, molecular profiling and age and stage at presentation. Attention is drawn to the disparity in the drug approvals and reimbursement strategies, between the different regions of Asia.

Imaging Evaluation of Peritoneal Metastasis: Current and Promising Techniques

Early diagnosis, accurate assessment, and localization of peritoneal metastasis (PM) are essential for the selection of appropriate treatments and surgical guidance. However, available imaging modalities (computed tomography [CT], conventional magnetic resonance imaging [MRI], and 18fluorodeoxyglucose positron emission tomography [PET]/CT) have limitations. The advent of new imaging techniques and novel molecular imaging agents have revealed molecular processes in the tumor microenvironment as an application for the early diagnosis and assessment of PM as well as real-time guided surgical resection, which has changed clinical management. In contrast to clinical imaging, which is purely qualitative and subjective for interpreting macroscopic structures, radiomics and artificial intelligence (AI) capitalize on high-dimensional numerical data from images that may reflect tumor pathophysiology. A predictive model can be used to predict the occurrence, recurrence, and prognosis of PM, thereby avoiding unnecessary exploratory surgeries. This review summarizes the role and status of different imaging techniques, especially new imaging strategies such as spectral photon-counting CT, fibroblast activation protein inhibitor (FAPI) PET/CT, near-infrared fluorescence imaging, and PET/MRI, for early diagnosis, assessment of surgical indications, and recurrence monitoring in patients with PM. The clinical applications, limitations, and solutions for fluorescence imaging, radiomics, and AI are also discussed.

Prognostic value of hyperthermic intraperitoneal chemotherapy in gastric cancer with synchronous peritoneal metastases: a real-world retrospective study

PURPOSE

Peritoneal metastasis in gastric cancer (GC) is a late-stage condition with a poor prognosis. Cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is a popular treatment for peritoneal metastases. Here, we aim to investigate the real-world application and efficacy of HIPEC alone for GC patients with synchronous peritoneal metastases.

METHODS

We conducted a retrospective analysis on GC patients with synchronous peritoneal metastasis at the Sixth Affiliated Hospital of Sun Yat-sen University between January 2011 and December 2022. Survival analyses and Cox regression models were performed based on overall survival (OS) and cancer-specific survival (CSS), and subgroup analysis was used to determine the prognostic value of HIPEC across different treatment.

RESULTS

We enrolled 250 patients, of whom 120 (48%) received HIPEC while 130 (52%) did not. HIPEC showed no survival benefit for GC patients (P = 0.220 for OS and P = 0.370 for CSS). However, subgroup analysis found that HIPEC can only improve OS and CSS when combined with primary tumor resection (P = 0.034 for OS and P = 0.036 for CSS). Moreover, survival analyses also demonstrated that HIPEC independently improved OS (HR for OS = 0.58, 95% CI 0.37-0.92, P = 0.020) and CSS (HR for CSS = 0.58, 95% CI 0.37-0.93, P = 0.024) for patients who underwent primary site resection, but not for those who did not.

CONCLUSION

HIPEC can improve survival in GC patients with synchronous peritoneal metastases who have primary tumor resection, but not in those without primary tumor resection.

CT-based deep learning model: a novel approach to the preoperative staging in patients with peritoneal metastasis

Peritoneal metastasis (PM) is a frequent manifestation of advanced abdominal malignancies. Accurately assessing the extent of PM before surgery is essential for patients to receive optimal treatment. Therefore, we propose to construct a deep learning (DL) model based on enhanced computed tomography (CT) images to stage PM preoperatively in patients. All 168 patients with PM underwent contrast-enhanced abdominal CT before either open surgery or laparoscopic exploration, and peritoneal cancer index (PCI) was used to evaluate patients during the surgical procedure. DL features were extracted from portal venous-phase abdominal CT scans and subjected to feature selection using the Spearman correlation coefficient and LASSO. The performance of models for preoperative staging was assessed in the validation cohort and compared against models based on clinical and radiomics (Rad) signature. The DenseNet121-SVM model demonstrated strong patient discrimination in both the training and validation cohorts, achieving AUC was 0.996 in training and 0.951 validation cohort, which were both higher than those of the Clinic model and Rad model. Decision curve analysis (DCA) showed that patients could potentially benefit more from treatment using the DL-SVM model, and calibration curves demonstrated good agreement with actual outcomes. The DL model based on portal venous-phase abdominal CT accurately predicts the extent of PM in patients before surgery, which can help maximize the benefits of treatment and optimize the patient's treatment plan.

Current Evidence for the Use of HIPEC and Cytoreductive Surgery in Gastric Cancer Metastatic to the Peritoneum

Gastric cancer (GCa) is an aggressive malignancy, representing the third leading cause of cancer mortality worldwide. The poor prognosis of GCa can be associated with the prevalence of peritoneal metastasis (PM). Current international and national GCa treatment guidelines only recommend palliative treatment options for patients with PM. Since the 1980s there have been multiple single arm trials, randomized controlled trials, and metanalysis investigating the use of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with advanced GCa, with or without PM. Results from these studies have been encouraging, with some large-volume centers even incorporating HIPEC into their treatment algorithms for patients with advanced GCa. Additionally, there are several ongoing trials that, when completed, will increase our understanding of the efficacy of CRS & HIPEC in patients with GCa metastatic to the peritoneum. Herein we review the current evidence, ongoing trials, consensus guidelines, and future considerations regarding the use of CRS & HIPEC in patients suffering from GCa with PM.

Bidirectional Approach with PIPAC and Systemic Chemotherapy for Patients with Synchronous Gastric Cancer Peritoneal Metastases (GCPM)

BACKGROUND

This study evaluated the efficacy of pressurized intraperitoneal aerosol chemotherapy (PIPAC) with systemic chemotherapy as a bidirectional approach for gastric cancer (GC) patients with synchronous peritoneal metastases (SPM).

METHODS

A retrospective analysis of a prospective PIPAC database was queried for patients who underwent a bidirectional approach between October 2019 and April 2022 at two high-volume GC surgery units in Italy (Verona and Siena). Surgical and oncological outcomes were analyzed.

RESULTS

Between October 2019 and April 2022, 74 PIPAC procedures in 42 consecutive patients with Eastern Cooperative Oncology Group performance status ≤2 were performed-32 patients treated in Verona and 10 in Siena. Twenty-seven patients (64%) were female and median age at first PIPAC was 60.5 years (I-III quartiles: 49-68 years). Median Peritoneal Cancer Index (PCI) was 16 (I-III quartiles: 8-26) and 25 patients (59%) had at least two PIPAC procedures. Major complications according to the Common Terminology Criteria for Adverse Events (CTCAE; 3 and 4) occurred in three (4%) procedures, and, according to the Clavien-Dindo classification (>3a), one (1%) severe complication occurred. There were no reoperations or deaths within 30 days. Median overall survival (mOS) from diagnosis was 19.6 months (range 14-24), and mOS from first PIPAC was 10.5 months (range 7-13). Excluding cases with very heavy metastatic peritoneal burden, with PCI from 2 to 26, treated with more than one PIPAC, mOS from diagnosis was 22 months (range 14-39). Eleven patients (26%) underwent curative-intent surgery after a bidirectional approach. R0 was achieved in nine (82%) patients and complete pathological response was obtained in three (27%) cases.

CONCLUSIONS

Patient selection is associated with bidirectional approach efficacy and feasibility for SPM GC treatment, which may allow potentially curative surgical radicalization in highly selected cases.

Molecular profile of poorly cohesive gastric carcinoma with special reference to survival

BACKGROUND

Patients with poorly cohesive gastric carcinoma (PCC) are known to have poor survival. However, detailed molecular biology of PCC has not been elucidated, except for mutations in CDH1 and RHOA. Additionally, the molecular profiles of signet-ring cell carcinoma (SRC) have not been fully investigated. We aimed to investigate the association between molecular profiles and survival in PCC and PCC subtypes.

METHODS

The present study included 455 patients with gastric adenocarcinoma underwent radical gastrectomy. Whole-exome sequencing and gene expression profiling were conducted. Patients were classified according to the WHO classification as PCC or non-PCC, with PCC being further classified into SRC, combined, and PCC not-otherwise-specified (NOS). Clinicopathological factors and survival were compared with molecular profiles.

RESULTS

Of the patients, 159 were classified with PCC, while 296 were classified with non-PCC. Among PCC, 44 were classified with SRC, 64 with combined, and 51 with PCC-NOS. Mutations in CDH1 and RHOA were remarkably more frequent in PCC than in non-PCC. PCC had worse overall survival (OS) and disease-specific survival (DSS) compared to non-PCC. For PCC, the SRC group had good OS and DSS, whereas PCC-NOS classification with CDH1 mutations was associated with extremely poor survival. In the PCC-NOS and combined groups, patients with mutations in the extracellular domain 1 of CDH1 had poor survival.

CONCLUSIONS

Our findings suggest that PCC has poorer survival than non-PCC. Accumulation of CDH1 and RHOA mutations are unique profiles in PCC. Among PCC, CDH1 mutations may play a crucial role in the survival of non-SRC PCC.

Gastric Cancer (GC) with Peritoneal Metastases (PMs): An Overview of Italian PSM Oncoteam Evidence and Study Purposes

Gastric cancer (GC) continues to be one of the leading types of malignancies worldwide, despite an ongoing decrease in incidence. It is the fifth most frequent type of cancer in the world and the fourth leading cause of cancer death. Peritoneal metastases (PMs) occur in 20-30% of cases during the natural history of the disease. Systemic chemotherapy (SC) is undoubtedly the standard of care for patients with GC and PMs. However, with the development of highly effective regimens (SC combined with intraperitoneal chemotherapy), significant tumor shrinkage has been observed in many patients with synchronous GC and PMs, allowing some to undergo curative resection "conversion surgery" with long-term survival. In recent years, there has been growing interest in intraperitoneal chemotherapy for PMs, because the reduced drug clearance associated with the peritoneal/plasma barrier allows for direct and prolonged drug exposure with less systemic toxicity. These procedures, along with other methods used for peritoneal surface malignancies (PSMs), can be used in GCs with PMs as neoadjuvant chemotherapy or adjuvant treatments after radical surgery or as palliative treatments delivered either laparoscopically or-more recently-as pressurized intraperitoneal aerosol chemotherapy. The great heterogeneity of patients with stage IV gastric cancer did not allow us to carry out a systemic review; therefore, we limited ourselves to providing readers with an overview to clarify the indications and outcomes of integrated treatments for GCs with PMs by analyzing reports from the international clinical literature and the specific experiences of our oncoteam.

Clinical Management of Gastric Cancer Treatment Regimens

Gastric cancer is the fifth most common cancer and the fourth leading cause of cancer-associated death in the world. Endoscopic resection can be the treatment in selected cases of very early gastric cancer. Surgery is recommended for tumors that do not meet the criteria for endoscopic resection or for tumors with lymph node invasion but without distant metastases. Gastrectomy should include D2 lymphadenectomy without splenectomy. Perioperative or adjuvant chemotherapy improves survival and is recommended in locally advanced gastric cancer (>T1 and/or with lymph nodes positive). In locally advanced cancer with microsatellite instability (MSI), immunotherapy should be considered. Advanced unresectable or metastatic gastric cancer has a poor prognosis. The basis of the treatment is cytotoxic chemotherapy, with platinum and fluoropyrimidine doublet in the first line. Targeted therapies can be combined with chemotherapy. Trastuzumab (anti-HER2) is recommended in the first line in HER2-positive cancer. Ramucirumab (anti-VEGFR2) is recommended in the second line, in addition to paclitaxel chemotherapy. Zolbetuximab (anti-Claudine 18.2) should also be considered in the first line in Claudine 18.2-positive cancer. Immunotherapy can also be associated with chemotherapy in the first line of PD-L1-positive cancer. In HER2-positive and PD-L1-positive cancer, adjunction of trastuzumab and immunotherapy should be considered. In advanced and metastatic cancer with microsatellite instability (MSI), immunotherapy should be the first choice depending on its availability. Important progress has been made in recent years in the treatment of gastric cancer, especially due to a better understanding of molecular characteristics and heterogeneity of this disease. New targets and therapeutic approaches are being developed, which will very likely lead to changes in the management of gastric cancer.

Gastric adenocarcinoma: A review of the TNM classification system and ways of spreading

Gastric cancer is the fifth most common cancer in the world. The most common histologic subtype is adenocarcinoma. Gastric adenocarcinomas are staged using the American Joint Committee on Cancer's 8th TNM classification. The perigastric ligaments, mesentery, omentum, and potential spaces between the parietal and visceral peritoneal linings play are important structures for staging. The spread of disease is influenced by the location of the tumor within the stomach, as well as by the anatomy related to the ligaments and lymph vessels. CT is the imaging modality of choice for the preoperative clinical staging of gastric cancer, and it is essential for planning treatment. To be able to do an adequate imaging workup, radiologists need to know the different pathways through which gastric cancer can spread: lymphatic, subperitoneal, direct invasion, transperitoneal, hematogenous, and extramural venous invasion.

Advances in the management of peritoneal malignancies

Peritoneal surface malignancies (PSMs) are usually associated with a poor prognosis. Nonetheless, in line with advances in the management of most abdominopelvic metastatic diseases, considerable progress has been made over the past decade. An improved understanding of disease biology has led to the more accurate prediction of neoplasia aggressiveness and the treatment response and has been reflected in the proposal of new classification systems. Achieving complete cytoreductive surgery remains the cornerstone of curative-intent treatment of PSMs. Alongside centralization in expert centres, enabling the delivery of multimodal and multidisciplinary strategies, preoperative management is a crucial step in order to select patients who are most likely to benefit from surgery. Depending on the specific PSM, the role of intraperitoneal chemotherapy and of perioperative systemic chemotherapy, in particular, in the neoadjuvant setting, is established in certain scenarios but questioned in several others, although more prospective data are required. In this Review, we describe advances in all aspects of the management of PSMs including disease biology, assessment and improvement of disease resectability, perioperative management, systemic therapy and pre-emptive management, and we speculate on future research directions.

Comprehensive Treatment Algorithms of the Swiss Peritoneal Cancer Group for Peritoneal Cancer of Gastrointestinal Origin

Peritoneal cancer (PC) is a dire finding, yet in selected patients, long-term survival is possible. Complete cytoreductive surgery (CRS) together with combination immunochemotherapy is essential to achieve cure. Hyperthermic intraperitoneal chemotherapy (HIPEC) and pressurized intraperitoneal aerosol chemotherapy (PIPAC) are increasingly added to the multimodal treatment. The Swiss Peritoneal Cancer Group (SPCG) is an interdisciplinary group of expert clinicians. It has developed comprehensive treatment algorithms for patients with PC from pseudomyxoma peritonei, peritoneal mesothelioma, gastric, and colorectal origin. They include multimodal neoadjuvant treatment, surgical resection, and palliative care. The indication for and results of CRS HIPEC and PIPAC are discussed in light of the current literature. Institutional volume and clinical expertise required to achieve best outcomes are underlined, while inclusion of patients considered for CRS HIPEC and PIPAC in a clinical registry is strongly advised. The present recommendations are in line with current international guidelines and provide the first comprehensive treatment proposal for patients with PC including intraperitoneal chemotherapy. The SPCG comprehensive treatment algorithms provide evidence-based guidance for the multimodal care of patients with PC of gastrointestinal origin that were endorsed by all Swiss clinicians routinely involved in the multimodal care of these challenging patients.

Integration of Genomic Biology Into Therapeutic Strategies of Gastric Cancer Peritoneal Metastasis

The peritoneum is a common site of metastasis in advanced gastric cancer (GC). Diagnostic laparoscopy is now routinely performed as part of disease staging, leading to an earlier diagnosis of synchronous peritoneal metastasis (PM). The biology of GCPM is unique and aggressive, leading to a dismal prognosis. These tumors tend to be resistant to traditional systemic therapy, and yet, this remains the current standard-of-care recommended by most international clinical guidelines. As this is an area of unmet clinical need, several translational studies and clinical trials have focused on addressing this specific disease state. Advances in genomic sequencing and molecular profiling have revealed several promising therapeutic targets and elucidated novel biology, particularly on the role of the surrounding tumor microenvironment in GCPM. Peritoneal-specific clinical trials are being designed with a combination of locoregional therapeutic strategies with systemic therapy. In this review, we summarize the new knowledge of cancer biology, advances in surgical techniques, and emergence of novel therapies as an integrated strategy emerges to address GCPM as a distinct clinical entity.

Poorly cohesive cells gastric carcinoma including signet-ring cell cancer: Updated review of definition, classification and therapeutic management

While the incidence of gastric cancer (GC) in general has decreased worldwide in recent decades, the incidence of diffuse cancer historically comprising poorly cohesive cells-GC (PCC-GC) and including signet ring cell cancer is rising. Literature concerning PCC-GC is scarce and unclear, mostly due to a large variety of historically used definitions and classifications. Compared to other histological subtypes of GC, PCC-GC is nevertheless characterized by a distinct set of epidemiological, histological and clinical features which require a specific diagnostic and therapeutic approach. The aim of this review was to provide an update on the definition, classification and therapeutic strategies of PCC-GC. We focus on the updated histological definition of PCC-GC, along with its implications on future treatment strategies and study design. Also, specific considerations in the diagnostic management are discussed. Finally, the impact of some recent developments in the therapeutic management of GC in general such as the recently validated taxane-based regimens (5-Fluorouracil, leucovorin, oxaliplatin and docetaxel), the use of hyperthermic intraperitoneal chemotherapy as well as pressurized intraperitoneal aerosol chemotherapy and targeted therapy have been reviewed in depth for their relative importance for PCC-GC in particular.

Impact of Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy in the Treatment of Gastric Cancer with Peritoneal Carcinomatosis: A Systematic Review and Meta-analysis

BACKGROUND

Despite promising results, the effectiveness of cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with gastric cancer with peritoneal carcinomatosis (GCPC) has not been systematically evaluated. The aim of this systematic review is to compare the survival, complications and risk of recurrence between CRS + HIPEC versus CRS alone in GCPC.

PATIENTS AND METHODS

A systematic review was performed in MEDLINE and Web of Science according to the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines. Primary studies with patients with GCPC older than 18 years were included. Methodological Index for Non-randomized Studies (MINORS) criteria were used to assess the quality of the studies. We performed random-effects meta-analysis of risk ratios (RR). We assessed heterogeneity using the I² statistic.

RESULTS

Five studies were included in the qualitative and four in the quantitative analysis. The overall survival (OS) rate after 1 year was 3.65 times higher for CRS + HIPEC than CRS alone [RR = 3.65, 95% confidence interval (95% CI) = 1.01-13.26, I² = 73%]. The OS rate after 5 years was more than three times higher for CRS + HIPEC than for CRS alone (RR = 3.25, 95% CI = 1.28-8.26, I² = 8%). No significant differences between CRS + HIPEC and CRS alone related to complications were found (RR = 1.05, 95% CI = 0.83-1.33, I² = 0%). The risk of peritoneal recurrence was significantly lower for CRS + HIPEC than for CRS alone (RR = 0.23, 95% CI = 0.11-0.48, I² = 40%). The results may be associated with some information or indication bias.

CONCLUSIONS

Results should be analysed cautiously given the detected heterogeneity and limitations of included studies. However, treatment with CRS + HIPEC seems to increase the survival of patients with GCPC, more than treatment with CRS alone, decrease the risk of peritoneal recurrence and not be associated with more complications.

Pressurized intraperitoneal aerosol chemotherapy (PIPAC) in multimodal therapy for patients with oligometastatic peritoneal gastric cancer: a randomized multicenter phase III trial PIPAC VEROne

Objectives

Peritoneal carcinomatosis is the most frequent site of metastases in patients with gastric cancer. Current standard treatment is palliative systemic chemotherapy with very poor prognosis. Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) resulted in long-term benefits in selected patients. Among patients with peritoneal carcinomatosis, a distinctive subset is oligometastatic disease which is characterized by low metastatic burden. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a recent technique of intraperitoneal chemotherapy used in combination with systemic chemotherapy with promising results.

Methods

PIPAC VER-One is a prospective, randomized, multicenter phase III clinical trial that aims to evaluate the effectiveness of the use of PIPAC in combination with systemic chemotherapy in patients with gastric cancer and synchronous positive peritoneal cytology and/or limited peritoneal metastases (peritoneal cancer index [PCI] ≤6). Patients will be randomized into two arms: arm A (control) treated with standard systemic chemotherapy and arm B (experimental) treated with a bidirectional scheme including PIPAC and systemic chemotherapy.

Results

Primary endpoint is the secondary resectability rate. Secondary endpoints are: overall survival (OS), pregression-free survival (PFS), disease-free survival (DFS), histological response assessed both on primary tumor and peritoneal lesions, quality of life (QoL), complication rate (CTCAE v5), and incremental cost-effectiveness ratios (ICER).

Conclusions

The role of PIPAC in multimodal treatment for oligometastatic gastric cancer will be investigated in this trial.

Cytoreductive Surgery for Peritoneal Carcinomatosis from Gastric Cancer: Technical Details

Due to limited systemic treatment options, peritoneal carcinomatosis of gastric origin is still associated with a dismal outcome and is claimed a terminal disease. In the past, surgery had not been considered as a potential treatment option. However, there is emerging evidence that in selected patients, locoregional treatment modalities including cytoreductive surgery of peritoneal carcinomatosis can improve survival in patients with gastric cancer. These operative procedures are complex and challenging, and a high surgical expertise of the treating physician is necessary to prevent major postoperative morbidity and mortality with a delay of further systemic therapy. This review summarizes our current knowledge and personal experience regarding the techniques of cytoreductive surgery for peritoneal metastasis of gastric origin.

Laparoscopic Heated Intraperitoneal Chemotherapy in the Treatment of Carcinomatosis of Gastric Adenocarcinoma Origin

The use of heated intraperitoneal chemotherapy (HIPEC) in conjunction with cytoreductive surgery has been gaining increasing traction in treating gastric adenocarcinoma with metastasis to the peritoneum in recent years. The addition of laparoscopic HIPEC (LS-HIPEC) to these treatment algorithms has increased the flexibility and adaptability of HIPEC integrating into treatment sequencing, allowing for iterative protocols of LS-HIPEC prior to cytoreduction as neoadjuvant treatment, as well as in the palliation of patients with unresectable disease and uncontrolled ascites. As the use of HIPEC in gastric adenocarcinoma continues to be refined, LS-HIPEC algorithms should continue to be considered and utilized both in curative treatment algorithms as well as in patients in the palliative setting. Given that LS-HIPEC remains a relatively nascent treatment modality, we advocate for its use in the setting of a clinical trial when feasible.