Evolving Treatment Strategies and Outcomes in Advanced Gastric Cancer with Peritoneal Metastasis

Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) in the Treatment of Gastric Cancer: Feasibility, Efficacy and Safety-A Systematic Review and Meta-Analysis

Background: Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) is an emerging technique for delivering chemotherapy directly to the peritoneum via a pressurized aerosol. Its growing attention stems from its effectiveness in treating peritoneal carcinomatosis (PC) originating from various primary tumors, with gastric cancer (GC) being among the most prevalent. This study aimed to systematically investigate PIPAC's therapeutic role in gastric cancer peritoneal metastasis (GCPM). Methods: The systematic review and meta-analysis followed the PRISMA 2020 guidelines, searching Pubmed, Web of Science, and SCOPUS databases. The meta-analysis of relative risks and mean differences compared patients undergoing one or two PIPAC sessions with those completing three or more, assessing various outcomes. Results: Eighteen studies underwent qualitative analysis, and four underwent quantitative analysis. Patients with three or more PIPAC procedures had shorter hospital stays (MD = -1.2; 95%CI (-1.9; -0.5); p < 0.001), higher rates of histopathological response (RR = 1.77, 95%CI 1.08; 2.90; p = 0.023), and significantly improved overall survival (MD = 6.0; 95%CI 4.2; 7.8; p < 0.001). Other outcomes showed no significant differences. Conclusions: PIPAC demonstrated efficacy in carefully selected patients, enhancing histopathologic response rates and overall survival without prolonging hospital stays. This study underscores the necessity for randomized controlled trials and precise selection criteria to refine PIPAC's implementation in clinical practice.

Hyperthermic intraperitoneal chemotherapy (HIPEC) plus systemic chemotherapy versus systemic chemotherapy alone in locally advanced gastric cancer after D2 radical resection: a randomized-controlled study

BACKGROUND

Currently, there is a lack of an effective strategy for the prevention of peritoneal metastasis (PM) from locally advanced gastric cancer (AGC). This randomized-controlled study aimed to evaluate the outcome of D2 radical resection with hyperthermic intraperitoneal chemotherapy (HIPEC) plus systemic chemotherapy versus systemic chemotherapy alone in locally AGC patients.

METHODS

All enrolled patients were randomly assigned to receive HIPEC plus systemic chemotherapy (HIPEC group) or systemic chemotherapy alone (non-HIPEC group) after radical gastrectomy. HIPEC was performed intraperitoneally with cisplatin (40 mg/m2) within 72 h after surgery, while systemic chemotherapy based on the SOX regimen (S-1 combined with oxaliplatin) was administered 4-6 weeks after radical surgery. Patterns of recurrence, adverse events, 3-year disease-free survival (DFS), and overall survival (OS) were analyzed.

RESULTS

A total of 134 patients were enrolled in the present study. The 3-year DFS rate was 73.8% in the HIPEC group, which was significantly higher than that in the non-HIPEC group (61.2%, P = 0.031). The 3-year OS rate was 73.9% in the HIPEC group and 77.6% in the non-HIPEC group, with no significant difference (P = 0.737). PM was the most common distant metastasis in both groups. The occurrence rate of PM in the HIPEC group was statistically lower than that in the non-HIPEC group (20.9% vs. 40.3%, P = 0.015). Grade 3 or 4 adverse events occurred in 19 (14.2%) patients, and there was no significant difference between the two groups.

CONCLUSION

Radical surgery followed by HIPEC combined with systemic chemotherapy is a safe and feasible strategy for locally AGC patients and could effectively improve DFS and reduce the occurrence of PM. However, more prospective randomized studies with a large sample size are warranted.

TRIAL REGISTRATION

This study was registered with www.medresman.org.cn as ChiCTR2200055966 on 10/12/2016.

Highly Sensitive Circulating Tumor DNA Assay Aids Clinical Management of Radiographically Occult Isolated Peritoneal Metastases in Patients With GI Cancer

PURPOSE

GI cancers commonly spread to the peritoneal cavity, particularly from primary adenocarcinomas of the stomach and appendix. Peritoneal metastases are difficult to visualize on cross-sectional imaging and cause substantial morbidity and mortality. The purpose of this study was to determine whether serial highly sensitive tumor-informed circulating tumor DNA (ctDNA) measurements could longitudinally track changes in disease burden and inform clinical care.

METHODS

This was a retrospective case series of patients with gastric or appendiceal adenocarcinoma and isolated peritoneal disease that was radiographically occult. Patients underwent quantitative tumor-informed ctDNA testing (Signatera) as part of routine clinical care. No interventions were prespecified based on ctDNA results.

RESULTS

Of 13 patients studied, the median age was 65 (range, 45-75) years, with 7 (54%) women, 5 (38%) patients with gastric, and 8 (62%) patients with appendiceal adenocarcinoma. Eight (62%) patients had detectable ctDNA at baseline measurement, with median value 0.13 MTM/mL (range, 0.06-11.68), and assay was technically unsuccessful in two cases with appendiceal cancer because of limited tumor tissue. Five (100%) patients with gastric cancer and 3 (50%) patients with appendiceal cancer had detectable ctDNA at baseline. Although baseline levels of ctDNA were low, longitudinal assessment tracked with changes in disease burden among patients undergoing chemotherapy for metastatic disease. In two patients undergoing surveillance after definitive surgical management of gastric adenocarcinoma, detection of ctDNA prompted diagnosis of isolated peritoneal disease.

CONCLUSION

Quantitative tumor-informed serial ctDNA testing aids clinical management of patients with isolated peritoneal disease. Low levels of baseline ctDNA suggest a role for highly sensitive ctDNA approaches over panel-based testing. Further exploration of this approach should be considered in patients with isolated peritoneal malignant disease.

Pharmacologic Targeting of MMP2/9 Decreases Peritoneal Metastasis Formation of Colorectal Cancer in a Human Ex Vivo Peritoneum Culture Model

Simple Summary

We investigated the effects of matrix metalloproteinases (MMPs) on the peritoneal attachment of colorectal cancer cells in patient samples and in a human ex vivo peritoneum model. MMP2/9 overexpression and enhanced fibronectin cleavage occurred during peritoneal colonisation, which could be inhibited by specific MMP inhibition, thereby reducing cancer cell attachment.

Abstract

Background: Matrix metalloproteinases (MMPs) play a crucial role in tumour initiation, progression, and metastasis, including peritoneal carcinosis (PC) formation. MMPs serve as biomarkers for tumour progression in colorectal cancer (CRC), and MMP overexpression is associated with advanced-stage metastasis and poor survival. However, the molecular mechanisms of PC from CRC remain largely unclear. Methods: We investigated the role of MMPs during peritoneal colonisation by CRC cell lines in a human ex vivo peritoneum model and in patient-derived CRC and corresponding PC samples. MMP2 and MMP9 were inhibited using the small-molecule inhibitors batimastat and the specific MMP2/9 inhibitor III. Results: MMP2 and MMP9 were strongly upregulated in patient-derived samples and following peritoneal colonisation by CRC cells in the ex vivo model. MMP inhibition with batimastat reduced colonisation of HT29 and Colo205 cells by 36% and 68%, respectively (p = 0.0073 and p = 0.0002), while MMP2/9 inhibitor III reduced colonisation by 50% and 41%, respectively (p = 0.0003 and p = 0.0051). Fibronectin cleavage was enhanced in patient-derived samples of PC and during peritoneal colonisation in the ex vivo model, and this was inhibited by MMP2/9 inhibition. Conclusion: MMPs were upregulated in patient-derived samples and during peritoneal attachment of CRC cell lines in our ex vivo model. MMP2/9 inhibition prevented fibronectin cleavage and peritoneal colonisation by CRC cells. MMP inhibitors might thus offer a potential treatment strategy for patients with PC.

Investigating the mechanisms of peritoneal metastasis in gastric adenocarcinoma using a novel ex vivo peritoneal explant model

Gastric adenocarcinoma, commonly known as stomach cancer, has a predilection for metastasis to the peritoneum, which portends limited survival. The peritoneal metastatic cascade remains poorly understood, and existing models fail to recapitulate key elements of the interaction between cancer cells and the peritoneal layer. To explore the underlying cellular and molecular mechanisms of peritoneal metastasis, we developed an ex vivo human peritoneal explant model. Fresh peritoneal tissue samples were suspended, mesothelial layer down but without direct contact, above a monolayer of red-fluorescent dye stained AGS human gastric adenocarcinoma cells for 24 h, then washed thoroughly. Implantation of AGS cells within the explanted peritoneum and invasion beyond the mesothelial layer were examined serially using real-time confocal fluorescence microscopy. Histoarchitecture of the explanted peritoneum was preserved over 5 days ex vivo. Both implantation and invasion were suppressed by restoration of functional E-cadherin through stable transfection of AGS cells, demonstrating sensitivity of the model to molecular manipulation. Thus, our ex vivo human peritoneal explant model permits meaningful investigation of the pathways and mechanism that contribute to peritoneal metastasis. The model will facilitate screening of new therapies that target peritoneal dissemination of gastric, ovarian and colorectal cancer.

Is PIPAC a Treatment Option in Upper and Lower Gastrointestinal Cancer with Peritoneal Metastasis?

Background

The survival prognosis of patients with peritoneal metastasis (PM) of gastrointestinal (GI) cancer is generally poor and treatment consists of, according to international guidelines, systemic chemotherapy. A multimodal treatment approach, including cytoreductive surgery with or without hyperthermic intraperitoneal chemotherapy, not only proved to be beneficial mainly in colorectal cancer, but also in selected patients with gastric cancer. The authors performed systematic research of articles and ongoing clinical trials using the keywords "PIPAC" and "gastric cancer" or "colorectal cancer" in PubMed in October 2021. Key findings, such as complications rates, treatment protocols, and overall survival were summarized and illustrated in Tables and critically discussed.

Summary

Twenty years ago, the technique of Pressurized IntraPeritoneal Aerosol Chemotherapy (PIPAC) was developed by Reymond et al. and delivered evidence to be recognized as a basic therapeutic tool in this multimodal therapy. Currently, there are several ongoing Phase II and III trials exploring the usage and efficacy of PIPAC as a neoadjuvant, adjuvant, or palliative component of treatment in patients with PM of GI cancer.

Key Messages

The aim of this narrative review was to help navigate the reader throughout the most current evidence for the use PIPAC and to highlight its indication in patients with upper and lower GI cancer with PM. It also provides an outline of ongoing studies and future perspectives.

Cost-effectiveness analysis of pressurized intraperitoneal aerosol chemotherapy (PIPAC) in patients with gastric cancer and peritoneal metastasis

OBJECTIVE

The aim of this study was to assess the cost-effectiveness of pressurized intraperitoneal aerosol chemotherapy with low-dose cisplatin and doxorubicin (PIPAC C/D) for the treatment of advanced gastric cancer.

METHODS

A Partitioned Survival Model followed by state transition Markov model was developed to estimate the costs and effectiveness of the use of PIPAC C/D versus palliative chemotherapy in the UK. The intervention was assessed at two different levels of care, including upfront therapy (PIPAC C/D plus Oxaliplatin in combination with Capecitabine (XELOX) chemotherapy versus first-line chemotherapy alone) and second-line therapy (PIPAC C/D alone versus second-line chemotherapy (ramucirumab monotherapy)). Data from multiple sources, including published literature and UK-based databases, were used to inform the economic model.

RESULTS

For the upfront therapy analysis, the estimated total costs in the intervention and comparator arms were £32,606 (SD: £3877) and £17,844 (SD: £920), respectively. PIPAC C/D plus XELOX led to an increase of 0.46 in quality-adjusted life-years (QALYs) gained. The incremental cost per QALY gained was £31,868. For the second-line therapy analysis, the use of PIPAC C/D led to an increase of 0.19 in QALYs and a £21,474 reduction in costs, meaning the intervention was a dominant strategy.

CONCLUSIONS

The cost-effectiveness results for the upfront therapy analysis indicate that PIPAC C/D plus chemotherapy is a cost-effective strategy. Additionally, PIPAC C/D alone as a second-line therapy has the potential to reduce costs and improve clinical outcomes for patients with advanced gastric cancer with peritoneal metastasis.

Neoadjuvant Intraperitoneal and Systemic Chemotherapy Versus Neoadjuvant Systemic Chemotherapy With Docetaxel, Oxaliplatin, and S-1 for Gastric Cancer With Peritoneal Metastasis: A Propensity Score Matched Analysis

BACKGROUND

The optimal treatment for gastric cancer with peritoneal metastasis (GCPM) remains debatable. This study aimed to compare the efficacy and safety of neoadjuvant intraperitoneal and systemic chemotherapy (NIPS) versus neoadjuvant systemic chemotherapy (NSC) for GCPM.

METHODS

Patients of GCPM received neoadjuvant chemotherapy with docetaxel, oxaliplatin and S-1 between January 2011 and June 2019 were retrospectively evaluated. Propensity score matched (PSM) analysis was carried out to reduce the selection bias. Multivariate Cox regression model was applied to screen the prognostic factors.

RESULTS

After PSM processing, 71 patients in each group were matched among the 186 GCPM patients included. NIPS yielded a better ascites and cytology response to chemotherapy, higher conversion resection rate and R0 resection rate than NSC. The overall survival (OS) rate in NIPS group was better than that in NSC group. Multivariate analysis revealed that the P stage, ascites response, conversion surgery rate and R0 resection rate were independent prognostic factors. Subgroup analysis indicated that NIPS showed a survival benefit over NSC only in patients with cT3-4a, P1-2, whose cytology turned negative, and who received conversion surgery; while not in patients with cT4b, P0 or P3, whose cytology did not turn negative, or who did not receive conversion surgery.

CONCLUSIONS

NIPS is a safe and feasible treatment for GCPM, which showed more benefit than NSC.

Beyond the Guidelines: The Grey Zones of the Management of Gastric Cancer. Consensus Statements from the Gastric Cancer Italian Network (GAIN)

BACKGROUND

Management of gastric and gastroesophageal junction (GEJ) adenocarcinoma remains challenging, because of the heterogeneity in tumor biology within the upper gastrointestinal tract. Daily clinical practice is full of grey areas regarding the complexity of diagnostic, staging, and therapeutic procedures. The aim of this paper is to provide a guide for clinicians facing challenging situations in routine practice, taking a multidisciplinary consensus approach based on available literature.

METHODS

The GAIN (GAstric cancer Italian Network) group was established with the aims of reviewing literature evidence, discussing key issues in prevention, diagnosis, and management of gastric and GEJ adenocarcinoma, and offering a summary of statements. A Delphi consensus method was used to obtain opinions from the expert panel of specialists.

RESULTS

Forty-nine clinical questions were identified in six areas of interest: role of multidisciplinary team; risk factors; diagnosis; management of early gastric cancer and multimodal approach to localized gastric cancer; treatment of elderly patients with locally advanced resectable disease; and treatment of locally advanced and metastatic cancer.

CONCLUSIONS

The statements presented may guide clinicians in practical management of this disease.

Transforming growth factor-β1 induces connective tissue growth factor expression and promotes peritoneal metastasis of gastric cancer

Transforming growth factor-β1 (TGF-β1) is involved in human cancer development and progression. Nonetheless, the role of TGF-β1 as regards peritoneal metastasis of gastric cancer has not been completely characterized. In the present study, we investigated the exact role of TGF-β1 on peritoneal metastasis of gastric cancer. The results indicated that human peritoneal mesothelial cells (HPMCs) exposed to TGF-β1 or serum-free conditional medium (SF-CM) of SGC7901 that produced a large amount of TGF-β1 became exfoliated, apoptosis and exhibited signs of injury, and the tumor-mesothelial cell adhesion significantly increased. Connective tissue growth factor (CTGF) expression was also increased when HPMCs were exposed to TGF-β1 or SF-CM of SGC7901. However, these effects were significantly decreased when HPMCs were exposed to SF-CM of SGC7901-TGFβS, a TGF-β1 knockdown stable cell line. Animal studies revealed that nude mice injected with SGC7901-TGFβS cells featured a smaller number of peritoneal seeding nodules and lower expression of CTGF in ascites than the control cell lines. These findings suggest that TGF-β1 promotes peritoneal metastasis of gastric cancer and induces CTGF expression. Therefore, blockage of TGF-β1 or TGF-β1 signaling pathway might prevent and treat peritoneal metastasis of gastric cancer.

Comparison of Docetaxel + Oxaliplatin + S-1 vs Oxalipatin + S-1 as Neoadjuvant Chemotherapy for Locally Advanced Gastric Cancer: A Propensity Score Matched Analysis

Background

What is the optimal neoadjuvant chemotherapy (NAC) regimen for locally advanced gastric cancer (LAGC) remains debatable. The objective of this study was to compare the efficacy of docetaxel+oxaliplatin+S-1 (DOS) vs oxaliplatin+S-1 (SOX) as NAC for LAGC.

Methods

Data of 248 LAGC patients who received either DOS or SOX as NAC in our hospital between January 2010 and January 2018 were reviewed retrospectively. Propensity score matched (PSM) analysis was applied to minimize the selection bias in both groups. Prognostic factors were screened by univariate and multivariate Cox regression analyses.

Results

Of the 248 LAGC patients included, 180 patients were subjected to the PSM analysis. Patients in DOS group showed a better tumor response to NAC, higher radical resection rate and R0 resection rate than those in SOX group. The overall survival (OS) rate in DOS group was better than that in SOX group, although the overall incidence of Grade 3/4 NAC-related toxicity in DOS group was higher, as represented by leukopenia and neutropenia. Multivariate analysis revealed that the NAC regimen, cTNM stage and the R0 resection rate were independent prognostic factors. In addition, patients with TLND less than 16 population showed a worse OS rate. Subgroup analysis indicated that patients benefited from the addition of docetaxel regardless of the clinical T stage, but those with high clinical N stages (N2-3) did not.

Conclusion

DOS is a safe and feasible NAC regimen for LAGC, which is worth popularizing in clinical practice.

Non-medical caregivers and the use of intraperitoneal chemotherapy in the operating theatre: A survey on the perception of safety

BACKGROUND

In the last two decades, intraperitoneal(IP) chemotherapy during surgery achieved recognition in the management of peritoneal metastases. Occupational hazard became a concern leading to standardized safety measures. The aim of this study is to evaluate the perceived level of information and protection among the non-medical caregivers involved in HIPEC and PIPAC in a high-volume center.

METHODS

All non-medical caregivers in the operating theatre of our institution were asked to answer a questionnaire between April and May 2018. The questionnaire included multiple choice questions and open questions structured in four parts: demographic variables, perceived level of information, perceived level of protection, interest in further education.

RESULTS

Forty-nine caregivers agreed to answer the questionnaire. All identified IP chemotherapy as an occupational risk. Thirty-eight persons (77.55%) trusted the protective value of safety measures during HIPEC compared to 32 (65.3%) during PIPAC. A total of 29 persons (59.18%) used some of the measures while 16 (32.65%) used all of them. Main reasons of non-use were slips and lapses (7 persons) and lack of comfort (4 persons). A total of 34 caregivers considered the level of information about safety protocols as good or very good (69%). A total of 46 persons considered the level of protection as satisfying or excellent (93.87%). A total of 36 (73.47%) interviewees expressed the need of receiving more information.

CONCLUSIONS

The present study shows that non-medical caregivers in the operating theatres are aware of the occupational hazards related to the use of IP chemotherapy. The use of protective measures is associated with decreased level of perceived risk. However there is a high need of continuous education on this subject for the involved personnel.

Reduced expression of exosomal miR‑29s in peritoneal fluid is a useful predictor of peritoneal recurrence after curative resection of gastric cancer with serosal involvement

The peritoneal surface is the most frequent site of metastasis disease in patients with gastric cancer. Even after curative surgery and adjuvant chemotherapy, peritoneal recurrences often develop. Exosomes play pivotal roles in tumor metastasis via the transfer of microRNAs (miRNAs). In the present study, exosomes were isolated from peritoneal lavage fluid or ascites in 85 patients with gastric cancer and the relative expression levels of miR-29s were examined. The expression of miR-29a-3p, miR-29b-3p and miR-29c-3p in peritoneal exosomes were all downregulated in patients with peritoneal metastases (PM) compared to those without PM. In 30 patients who underwent curative gastrectomy with serosa-involved (T4) gastric cancer, 6 patients exhibited recurrence in the peritoneum within 12 months. The expression levels of miR-29s at gastrectomy tended to be lower in these 6 patients than in the other 24 patients with significant differences in miR-29b-3p (P=0.003). When the patients were divided into two groups based on median levels of miR-29s, peritoneal recurrence developed more frequently in patients with low expression of miR-29b-3p, and lower expression of miR-29s were related with worse overall survival. miR-29s are thought to play a suppressive role in the growth of disseminated peritoneal tumor cells. Reduced expression of miR-29b in peritoneal exosomes is a strong risk factor of developing postoperative peritoneal recurrence.

shRNA-mediated inhibition of PhosphoGlycerate Kinase 1 (PGK1) enhances cytotoxicity of intraperitoneal chemotherapy in peritoneal metastasis of gastric origin

BACKGROUND

Phosphoglycerate kinase 1 (PGK1) plays metabolic, kinase and translational roles in Peritoneal metastasis (PM) of gastric origin and is associated with chemoresistance. Silencing PGK1 might potentiate the effect of chemotherapy.

METHODS

In an orthoptic xenograft nude mice model, human gastric cancer cells (MKN45) were grown in 22 donor animals. Solid tumors were then grafted into the gastric subserosa of 102 recipient animals and allowed to grow for 10 days. Animals were randomized into 7 groups: Five test groups: 1) Mitomycin C (MMC), 2) MMC and small hairpin RNA silencing of PGK1 with an adenoviral vector (Adv-shPGK1), 3) 5-fluorouracil (5-FU), 4) 5-FU and Adv-shPGK1, 5) Adv-shPGK1 alone; two control groups: 1) Sham (NaCl 0.9%), 2) empty viral vector. Intraperitoneal therapy was administered on postoperative day (POD) 11 and 18. Animals were sacrificed at POD 21, analysis was blinded to therapy.

RESULTS

Adding Adv-shPGK1 to 5-FU reduced the number (0.23 ± 0.43 vs. 1.36 ± 1.00, p = 0.005) and weight (0,005 ± 0.012 mg vs. 0.05 ± 0.08 mg, p = 0.002) of PM as compared to 5-FU alone. The effect of adding Adv-shPGK1 to MMC did not reach statistical significance. Mortality was not increased by adding Adv-shPGK1 to chemotherapy but was increased by Adv-shPGK1 alone as compared to sham.

CONCLUSION

In this experimental model, combined therapy with chemotherapy and Adv-shPGK1 improves control of PM of gastric origin as compared to chemotherapy alone and might counteract chemoresistance of PM. A systemic toxicity of Adv-shPGK1 cannot be excluded.

Overcoming Drug Resistance by Taking Advantage of Physical Principles: Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC)

Theoretical considerations as well as comprehensive preclinical and clinical data suggest that optimizing physical parameters of intraperitoneal drug delivery might help to circumvent initial or acquired resistance of peritoneal metastasis (PM) to chemotherapy. Pressurized Intraperitoneal Aerosol Chemotherapy (PIPAC) is a novel minimally invasive drug delivery system systematically addressing the current limitations of intraperitoneal chemotherapy. The rationale behind PIPAC is: (1) optimizing homogeneity of drug distribution by applying an aerosol rather than a liquid solution; (2) applying increased intraperitoneal hydrostatic pressure to counteract elevated intratumoral interstitial fluid pressure; (3) limiting blood outflow during drug application; (4) steering environmental parameters (temperature, pH, electrostatic charge etc.) in the peritoneal cavity for best tissue target effect. In addition, PIPAC allows repeated application and objective assessment of tumor response by comparing biopsies between chemotherapy cycles. Although incompletely understood, the reasons that allow PIPAC to overcome established chemoresistance are probably linked to local dose intensification. All pharmacological data published so far show a superior therapeutic ratio (tissue concentration/dose applied) of PIPAC vs. systemic administration, of PIPAC vs. intraperitoneal liquid chemotherapy, of PIPAC vs. Hyperthermic Intraperitoneal Chemotherapy (HIPEC) or PIPAC vs. laparoscopic HIPEC. In the initial introduction phase, PIPAC has been used in patients who were quite ill and had already failed multiple treatment regimes, but it may not be limited to that group of patients in the future. Rapid diffusion of PIPAC in clinical practice worldwide supports its potential to become a game changer in the treatment of chemoresistant isolated PM of various origins.

The use of intraperitoneal chemotherapy for gastric malignancies

Introduction: Gastric cancer is the fourth/fifth most common malignancy worldwide, with only a quarter of patients achieving a 5-year survival rate. It has been estimated that 15-50% or more of patients have peritoneal disease upon surgical exploration. Until the early 1990s, peritoneal metastasis was considered as terminal stage of the disease; in the late 1990s, selected patients with peritoneal metastasis were recategorized as local disease. Over the past two decades, the treatment of peritoneal involvement has transformed, and cytoreductive surgery plus intraperitoneal therapy have drastically altered the natural course of several malignancies. Areas covered: We performed a review of studies available on PubMed from 1 January 2014 to 31 July 2019 and the analysis of their reference citations. We describe the most current intraperitoneal chemotherapy opportunities in the treatment of gastric cancer: hyperthermic intraoperative intraperitoneal chemotherapy (HIPEC), laparoscopic hyperthermic intraperitoneal chemotherapy (LHIPEC), neoadjuvant intraperitoneal and systemic chemotherapy (NIPS), LHIPEC + NIPS, extensive intraoperative peritoneal lavage (EIPL), early postoperative intraperitoneal chemotherapy (EPIC), and pressurized intraperitoneal aerosol chemotherapy (PIPAC). Expert opinion: Comprehensive treatment consisting of CRS combined with perioperative intraperitoneal/systemic chemotherapy can, today, be considered an effective strategy to improve the long-term survival of gastric cancer patients with peritoneal metastasis.

SLAMF6 as a Regulator of Exhausted CD8+ T Cells in Cancer

The tumor microenvironment in leukemia and solid tumors induces a shift of activated CD8+ cytotoxic T cells to an exhausted state, characterized by loss of proliferative capacity and impaired immunologic synapse formation. Efficient strategies and targets need to be identified to overcome T-cell exhaustion and further improve overall responses in the clinic. Here, we took advantage of the Eμ-TCL1 chronic lymphocytic leukemia (CLL) and B16 melanoma mouse models to assess the role of the homophilic cell-surface receptor SLAMF6 as an immune-checkpoint regulator. The transfer of SLAMF6+ Eμ-TCL1 cells into SLAMF6-/- recipients, in contrast to wild-type (WT) recipients, significantly induced expansion of a PD-1+ subpopulation among CD3+CD44+CD8+ T cells, which had impaired cytotoxic functions. Conversely, administering anti-SLAMF6 significantly reduced the leukemic burden in Eμ-TCL1 recipient WT mice concomitantly with a loss of PD-1+CD3+CD44+CD8+ T cells with significantly increased effector functions. Anti-SLAMF6 significantly reduced leukemic burden in the peritoneal cavity, a niche where antibody-dependent cellular cytotoxicity (ADCC) is impaired, possibly through activation of CD8+ T cells. Targeting of SLAMF6 affected tumor growth not only in B cell-related leukemia and lymphomas but also in nonhematopoietic tumors such as B16 melanoma, where SLAMF6 is not expressed. In vitro exhausted CD8+ T cells showed increased degranulation when anti-human SLAMF6 was added in culture. Taken together, anti-SLAMF6 both effectively corrected CD8+ T-cell dysfunction and had a direct effect on tumor progression. The outcomes of our studies suggest that targeting SLAMF6 is a potential therapeutic strategy.

Pressurized intraperitoneal aerosol chemotherapy with low-dose cisplatin and doxorubicin (PIPAC C/D) in patients with gastric cancer and peritoneal metastasis: a phase II study

Background:

Efficacy of second-line systemic chemotherapy in recurrent gastric cancer with peritoneal metastasis (RGCPM) is limited. We assessed the feasibility, safety and possible efficacy of pressurized intraperitoneal aerosol chemotherapy (PIPAC) in patients with RGCPM after ⩾1 line of palliative intravenous chemotherapy.

Methods:

In this open-label, single-arm, monocentric phase II ICH-GCP clinical trial, patients were scheduled for three courses of PIPAC with cisplatin 7.5 mg/m² and doxorubicin 1.5 mg/m² (PIPAC C/D) every 6 weeks. Patients with bowel obstruction or extraperitoneal metastasis were ineligible. The primary endpoint was clinical benefit rate (CBR) by Response Evaluation Criteria in Solid Tumors based on clinical records. Secondary endpoints included overall survival (OS), median time to progression (TTP), peritoneal carcinomatosis index (PCI), histological regression and ascites volume. Safety and tolerability were assessed by Common Terminology Criteria for Adverse Events (CTCAE) version 4, quality of life (QoL) by EORTC-QLQ30 questionnaire.

Results:

A total of 25 patients were enrolled and available for the analysis of the primary endpoint. Of those 25 patients, 10 (40%) had a radiological complete, partial response or stable disease. Median OS [intention to treat (ITT)] was 6.7 months, median TTP was 2.7 months. Complete or major regression on histology were observed in 9/25 patients (36%, ITT) or 6/6 [100%, per protocol (PP)] patients. There were no suspected unexpected serious adverse reactions, no treatment-related deaths, no CTCAE grade 4 toxicity and three (12%) grade 3 toxicities. Changes in the QLQ-C30 scores during PIPAC C/D therapy were small and not significant.

Conclusions:

PIPAC C/D was well tolerated and active in patients with RGCPM. Survival was encouraging. Randomized controlled trials should now be designed in this indication.

Contemporary paradigm for the evaluation and treatment of hereditary gastric cancer

Gastric cancer is the third leading cause of cancer mortality worldwide. Survival is linked to stage at diagnosis and tolerance to surgery and adjuvant therapy. The emergence of sophisticated methods to identify patients at high risk for the development of gastric cancer has given us an opportunity to eliminate a lethal disease in an identifiable patient population. Guidelines and recommendations have been established and prophylactic total gastrectomy is considered the most effective treatment. However, this requires substantial physical and emotional investment. It is imperative that patients and families are supported by genetic counseling, ongoing surveillance, and survivorship studies.

Management Of Synchronous Krukenberg Tumors From Gastric Cancer: a Single-center Experience

Background: Whether metastasectomy improves prognosis of gastric cancer patients with ovarian metastases (Krukenberg tumors) is not clear. In this study, we examined the survival benefit of metastasectomy combined with chemotherapy for treatment of synchronous Krukenberg tumors from gastric cancer and identified the prognostic factors.

Methods: The subjects of this study were patients diagnosed as synchronous Krukenberg tumors of gastric origin in the period between December 2004 and December 2015. Patients were classified in accordance with treatment modality: metastasectomy group (metastasectomy combined with chemotherapy) and non-metastasectomy group (chemotherapy alone). Clinicopathological characteristics together with treatment records were investigated in detail and their relationship with survival outcomes was examined.

Results: Out of a total of 103 patients, 54 (52.4%) underwent metastasectomy of Krukenberg tumors while 49 (47.6%) patients had chemotherapy alone. Overall survival (OS) in the metastasectomy group was significantly longer than that in the non-metastasectomy group (18.9 months vs. 12.4 months, respectively; P<0.001). Metastasectomy (hazard ratio [HR] 0.486; 95% confidence interval [CI] 0.323-0.729; P<0.001), signet ring cells (HR 1.938; 95% CI 1.182-3.175; P=0.009), peritoneal carcinomatosis (HR 1.934; 95% CI 1.230-3.049; P=0.004), expression of estrogen receptor-β (ER-β) (HR 0.404; 95% CI 0.251-0.648; P<0.001), and progesterone receptor (PR) (HR 0.496; 95% CI 0.301-0.817; P<0.001) were independent predictors of OS.

Conclusion: Metastasectomy combined with chemotherapy showed an association with survival benefit in patients with synchronous Krukenberg tumors from gastric cancer. Metastasectomy, expression of ER-β and PR, peritoneal carcinomatosis, and signet ring cells were independent predictors of survival. Further prospective studies are warranted.