Pseudomyxoma Peritonei

This is a pilot, open-label clinical trial determining the feasibility of metformin therapy in subjects with pseudomyxoma peritonei (PMP) secondary to appendiceal mucinous neoplasms (AMNs).

The goal of this prospective phase 2 study is to assess the efficacy and safety of intestinal or multivisceral transplantation for participants with PMP not amenable to other curative-intent treatments. Participants will undergo intestinal/multivisceral transplantation. Participants will be followed for 12 months to assess efficacy and safety.

The Investigators are researching how to improve the treatment currently available for patients diagnosed with Pseudomyxoma Peritonei (PMP). This is a rare cancer that usually starts in the appendix and spreads around the abdomen. PMP is usually treated using a type of surgery called Cytoreductive Surgery (CRS). During the surgery heated chemotherapy will also be used to treat any cancer cells that cannot be seen and may be left behind. This is called Hyperthermic Intraperitoneal Chemotherapy (HIPEC). This treatment is commonly used in the UK and in Europe, however, the chemotherapy can be given at two different doses: a lower dose over 60 minutes or a higher-dose over 90 minutes. The Investigators want to understand if there is a difference between these two doses. The higher dose has been associated with a slightly increased rate of complications but may be better at killing cancer cells and preventing recurrence of cancer. In Basingstoke the lower dose over 60 minutes is used and survival results are similar to centres who use the higher dose. Previous studies have shown that both doses are effective at treating PMP, but no research has shown which is better for patients. The Investigators hope to show that the lower-dose over 60-minutes is as good as the higher-dose over 90-minutes.

This randomized controlled trial evaluates the efficacy of a proactive Goal-Directed Temperature Management (GDTM) protocol in reducing postoperative delirium among patients undergoing Cytoreductive Surgery (CRS) with Hyperthermic Intraperitoneal Chemotherapy (HIPEC) for pseudomyxoma peritonei. CRS-HIPEC presents a unique physiological challenge characterized by a biphasic thermal trajectory: potential hypothermia during extensive surgery followed by rapid iatrogenic hyperthermia during perfusion. This study compares a standardized GDTM strategy-which incorporates strict normothermia maintenance and anticipatory pre-cooling prior to perfusion-against standard reactive thermal management. The primary objective is to determine if optimized thermoregulation can attenuate thermal variability and improve early neurocognitive recovery.

The investigator proposes to use the cardiac coherence technique to diminish anxiety before the surgery of a peritoneal carcinosis of colon or stomach or ovary and pseudomyxoma or peritoneal mesothelioma.

Participants will receive vaccination with Pseudovax/GM-CSF in combination with PD-1 inhibitor tislelizumab over a period of up to two years. The vaccine is expected to reactivate measurable immune response, and tislelizumab to restore anticancer immunity in patients with GNAS mutated pseudomyxoma peritonei.

The goal of this clinical trial is to compare the efficacy and safety of one versus three sessions of hyperthermic intraperitoneal chemotherapy (HIPEC) after cytoreductive surgery (CRS) for patients with pseudomyxoma peritonei (PMP). The main questions it aims to answer are: * Does receiving three HIPEC sessions lead to better Progression-Free Survival (PFS) and Overall Survival (OS) compared to one session? * What are the differences in postoperative complications (e.g., infection, bowel obstruction, myelosuppression) and organ toxicity (e.g., liver/kidney injury) between the two regimens? * How do the different treatment schedules impact patients' quality of life? Researchers will compare the experimental group (3 HIPEC sessions) to the control group (1 HIPEC session) to investigate the efficacy and safety of the additional sessions. Participants will: * Be randomly assigned to one of two groups: 1. Control Group: Receive only a single intraoperative HIPEC session following CRS. 2. Experimental Group: Receive two additional HIPEC sessions after CRS+HIPEC (on post-operative day 2 and day 4) at reduced drug doses. * Undergo scheduled safety checks for side effects on days 1, 3, 5, 7, and 10 post-HIPEC. * Attend a follow-up visit at 1 month after CRS+HIPEC and, if eligible, receive 6 cycles of standard postoperative chemotherapy. * Attend regular long-term follow-up visits for several years, which will include physical examinations, blood tests (for tumor markers), CT scans, and quality-of-life questionnaires (EORTC QLQ-C30 version 3.0).

The goal of this clinical trial is to evaluate the safety and efficacy of neoadjuvant capecitabine and cyclophosphamide treatment in patients affected by huge Pseudomyxoma peritonei (PMP) (peritoneal cancer index \>28). Treatment consists of metronomic (low-dose medication for a prolonged time) of capecitabine plus cyclophosphamide for 6 months followed by standard of care cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). The main question the trial aims to answer is which is the proportion of patients with complete cytoreduction at CRS/HIPEC after neoadjuvant metronomic approach with oral capecitabine and cyclophosphamide in patients affected by huge PMP.

The purpose of this study is to register the follow-up data of patients who, because of a peritoneal surface malignancy, will undergo cytoreductive surgery and HIPEC.

The aim of this study is to identify biomarkers of disease recurrence and prognosis to optimize patient selection for treatment with cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC), and through animal models to explore different treatment strategies for peritoneal surface malignancies (PSM).