Biomarker Analysis of HIPEC Combined With PD1/PDL1 Inhibitor for Gastric Cancer With Peritoneal Metastasis

Study Overview
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Brief Summary
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A single-center, observational study, integrated biomarker analysis of HIPEC combined Programmed cell death 1 /Programmed cell death 1 ligand 1(PD1/PDL1)inhibitor in previously treated patients of advanced gastric cancer with peritoneal metastasis. Tests will be performed on tumor tissue and blood samples, and imaging assessments will be reviewed in order to monitor how well each patient responds to treatment. This is an observational study, so participants will not receive cancer treatment, other than the treatment received as standard of care.

Detailed Description
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To analyze the correlation between genomic alterations, gene expression characteristics and the efficacy of HIPEC combined with PD1/PDL1 inhibitor conversion therapy in patients with peritoneal metastasis of gastric cancer. Circulating tumor DNA(ctDNA) in plasma samples and DNA, RNA in tumor tissue sample were obtained over the course of HIPEC combined PD1/PDL1 inhibitor conversion treatment will be assessed by high-intensity, next-generation sequencing(NGS) to identify genomic alterations. The assay will performed used AmoyDx® Master Panel(Amoy Diagnostics Co., Xiamen, China), which contains 559 genes for DNA mutation detection and 1813 genes for RNA expression and fusion detection. Data acquired will be analyzed to characterize the association between these genetic elements, clinical response, and durability of responses. There will be prospective groups for the study. Samples will be collected from patients in the prospective cohort who have been treated with HIPEC combined PD1/PDL1 inhibitor at Affiliated Cancer Hospital & Institute of Guangzhou Medical University under standard of conversion treatment.

Official Title
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Integrated Biomarker Analysis for Hyperthermic Intraperitoneal Chemotherapy(HIPEC) Combined PD1/PDL1 Inhibitor Treatment in Patients of Advanced Gastric Cancer With Peritoneal Metastasis

Conditions
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Gastric Cancer

Intervention / Treatment
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* Other: Observational


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Advanced gastric (gastroesophageal junction) adenocarcinoma confirmed by histology; Age 18-75 years, Male or Non-pregnant female Eastern Cooperative Oncology Group(ECOG): 0 1； Negative for human epidermal growth factor receptor 2(HER-2) by immunocytochemistry or fluorescence in situ hybridization； The presence of gastric cancer peritoneal metastasis is confirmed by laparoscopic exploration, and the PCI≤20； Patients had received HIPEC combined with PD1/PDL1 inhibitor conversion therapy. Signed the Informed Consent Form, and blood and tissue samples can be obtained; Exclusion Criteria: Other distal metastases besides peritoneal metastases (e.g., liver, lung, pleural, brain, bone metastases, etc.); Other patients who were considered unsuitable for inclusion by the researchers;

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Prospective Sample Collection<br>Prospective sample collection from participants treated with HIPEC combined PD1/PDL1inhibitor at Affiliated Cancer Hospital & Institute of Guangzhou Medical University under standard of care treatment. Blood and tissue samples will be collected prior to initiation of conversion therapy. And thereafter at the four time points: before and after surgery(±7 days), before the start of the second cycle of adjuvant, tumour progression, blood sample will be collected too. | Other: Observational<br>* All patients will be treated with standard of conversion treatment with HIPEC combined PD1/PDL1 inhibitor. After obtaining written informed consent, participants will have serial blood, tumor tissue collection. The blood collection (10 ml) should coincide with routine clinical blood draw to minimize participant discomfort if possible. No additional procedures will be performed other than phlebotomy. Participants will remain on the study for as long as they are being followed or treated at Affiliated Cancer Hospital & Institute of Guangzhou Medical University. Participants can withdraw from the study at any time.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Relationship between the status, numerical changes of ctDNA during HIPEC combined with PD1/PDL1 inhibitor conversion therapy and postoperative R0 resection rate. | R0 resection rate refers to the proportion of all patients with negative margins under the microscope of tumor specimens after surgery to the total number of participants. To dynamically evaluate the ctDNA profiles by next-generation sequencing and illustrate the genomic changes of ctDNA at baseline, during treatment. | 3 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Genomic changes of ctDNA and see if they are predictive of ORR. | Objective response rate(ORR): ORR = (number of subjects with complete response (CR) + partial response (PR))/total number of subjects ×100%. Measurable lesion according to the Response Evaluation Criteria In Solid Tumours(RECISTv1.1). To dynamically evaluate the ctDNA profiles by next-generation sequencing and illustrate the genomic changes of ctDNA at baseline, during treatment. | 3 months | 
| Genomic changes of ctDNA and see if they are predictive of overall survival time. | Overall survival time(OS) refers to the time of first use of the drug to the time of death. At the end of the study, if the subject is still alive, refer the known date of last survival of the subject as the date of censoring. To dynamically evaluate the ctDNA profiles by next-generation sequencing and illustrate the genomic changes of ctDNA at baseline, during and after treatment. | 2 years | 
| Genomic changes of ctDNA and see if they are predictive of event-Free Survival. | Event-Free Survival(EFS): Defined as the interval between the first conversion therapy and the first recorded related events, including preoperative disease progression, postoperative disease recurrence, and death from any cause. To dynamically evaluate the ctDNA profiles by next-generation sequencing and illustrate the genomic changes of ctDNA at baseline, during and after treatment. | 2 years | 
| Genomic changes of ctDNA and see if they are predictive of relapse-Free Survival. | Relapse-Free Survival(RFS): Defined as postoperative the first recorded postoperative recurrence of disease or death from any cause. To dynamically evaluate the ctDNA profiles by next-generation sequencing and illustrate the genomic changes of ctDNA at baseline, during and after treatment. | 2 years | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Biomarker