Is Hyperthermic Intraperitoneal Chemotherapy Appropriate for Colon Cancer?

Colorectal cancer (CRC) with peritoneal metastases is a complex disease and its management presents significant clinical challenges. In well-selected patients at experienced centers, CRS/hyperthermic intraperitoneal chemotherapy (HIPEC) can be performed with acceptable morbidity and is associated with prolonged survival. Based on the results of recent randomized controlled trials, HIPEC using oxaliplatin after CRS with shortened perfusion periods (30 minutes) is no longer recommended. There is a movement toward utilizing mitomycin C as a first-line intraperitoneal agent with extended perfusion times (90-120 minutes); however, there is currently little prospective evidence to support its widespread use.

Long-Term Outcomes following Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Peritoneal Carcinomatosis of Colorectal Origin.

BACKGROUND: Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is a major treatment of colorectal peritoneal carcinomatosis (CPC). The aim was to determine the disease-free survival (DFS) and overall survival (OS) of patients undergoing CRS-HIPEC for CPC and factors associated with long-term survival (LTS). METHODS: consecutive CPC patients who underwent CRS-HIPEC at a HIPEC center between 2007 and 2021 were included. Actual survival was calculated, and Cox proportional hazards models were used to identify factors associated with OS, DFS and LTS. RESULTS: there were 125 patients with CPC who underwent primary CRS-HIPEC, with mean age of 54.5 years. Median follow-up was 31 months. Average intraoperative PCI was 11, and complete cytoreduction (CC-0) was achieved in 96.8%. Median OS was 41.6 months (6-196). The 2-year and 5-year OS were 68% and 24.8%, respectively, and the 2-year DFS was 28.8%. Factors associated with worse OS included pre-HIPEC systemic therapy, synchronous extraperitoneal metastasis, and PCI ≥ 20 (p < 0.05). Progression prior to CRS-HIPEC was associated with worse DFS (p < 0.05). Lower PCI, fewer complications, lower recurrence and longer DFS were associated with LTS (p < 0.05). CONCLUSION: CRS and HIPEC improve OS in CPC patients but they have high disease recurrence. Outcomes depend on preoperative therapy response, extraperitoneal metastasis, and peritoneal disease burden.

Progress on immuno-microenvironment and immune-related therapies in patients with pseudomyxoma peritonei.

Pseudomyxoma peritonei (PMP) is an indolent malignant syndrome. The standard treatment for PMP is cytoreductive surgery combined with intraperitoneal hyperthermic chemotherapy (CRS + HIPEC). However, the high recurrence rate and latent clinical symptoms and signs are major obstacles to further improving clinical outcomes. Moreover, patients in advanced stages receive little benefit from CRS + HIPEC due to widespread intraperitoneal metastases. Another challenge in PMP treatment involves the progressive sclerosis of PMP cell-secreted mucus, which is often increased due to activating mutations in the gene coding for guanine nucleotide-binding protein alpha subunit (GNAS). Consequently, the development of other PMP therapies is urgently needed. Several immune-related therapies have shown promise, including the use of bacterium-derived non-specific immunogenic agents, radio-immunotherapeutic agents, and tumor cell-derived neoantigens, but a well-recognized immunotherapy has not been established. In this review the roles of GNAS mutations in the promotion of mucin secretion and disease development are discussed. In addition, the immunologic features of the PMP microenvironment and immune-associated treatments are discussed to summarize the current understanding of key features of the disease and to facilitate the development of immunotherapies.

Nomogram to Predict Tube Occlusion During Hyperthermic Intraperitoneal Chemotherapy for Pseudomyxoma Peritonei.

OBJECTIVE: To investigate the factors contributing to the blockage of perfusion tubes during hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with appendiceal pseudomyxoma peritonei (PMP) undergoing combined cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy treatment, and to construct a nomogram for predicting the risk of tube occlusion. STUDY DESIGN: Observational study. Place and Duration of the Study: Department of Gastrointestinal Surgery, Central Hospital Affiliated to Shandong First Medical University, Jinan, China, from June 2017 to December 2023. METHODOLOGY: Tube occlusion was defined as the inability to achieve 30 minutes of continuous unobstructed perfusion. Statistical methods such as univariate analysis, multivariate analysis, and Lasso regression were employed for data analysis. RESULTS: The results revealed that 27% of the 383 hyperthermic intraperitoneal chemotherapy perfusion treatments resulted in the tube occlusion events. Multivariate logistic regression analysis identified age, CA-125, CA19-9, and pathological type as the independent risk factors. A nomogram predicting the tube occlusion was constructed and validated for its predictive accuracy and clinical utility. CONCLUSION: This study successfully developed a nomogram to predict the tube occlusion risk during cytoreductive surgery combined with hyperthermic intraperitoneal chemotherapy treatment for patients with pseudomyxoma peritonei, providing valuable guidance for clinical practice and aiding in personalised treatment decisions to improve patient prognosis. However, further research is needed to validate the reliability and clinical applicability of the model, as well as to investigate the impact of tube occlusion on treatment outcomes and corresponding management strategies. KEY WORDS: Pseudomyxoma peritonei, Cytoreductive surgery, Hyperthermic intraperitoneal chemotherapy treatment, Tube occlusion, Nomogram.

[Treatment strategies of cytoreductive surgery plus intraperitoneal hyperthermic chemotherapy for gastric cancer with peritoneal metastasis: a systematic review].

Peritoneal metastasis in gastric cancer is associated with rapid disease progression. Hyperthermic intraoperative peritoneal chemotherapy (HIPEC) done immediately after cytoreductive surgery (CRS) has become an important treatment for peritoneal metastasis in gastric cancer patients. However, different treatment options for HIPEC exist with potential influence on survival rates and prognosis in patients, exist. These treatment options include open or closed abdomen technique, perfusion solution, number of catheters, temperature, duration, and drug regimens. This paper aims to provide more evidence on standardization of HIPEC treatment options and technologies by systematically reviewing different drug regimens and technical approaches. The study included 2 randomized controlled trials, 3 phase I/II clinical trials, 2 prospective cohort studies, and 34 retrospective cohort studies, involving 1511 patients. The most common HIPEC option is to dissolve 50-75 mg/m2 of Cisplatin and 30-40 mg/m2 of Mitomycin C in 3-4 L saline solution at 42-43℃. After gastrointestinal anastomosis, 2-3 catheters are used in the HIPEC system with a perfusion flow rate of 500 ml/min. The duration is 60-90 minutes. Anastomotic leakage was low in studies where HIPEC was performed after gastrointestinal anastomosis. The utilization of open HIPEC and a two-drug regimen resulted in improved overall survival rates. The future development of HIPEC aims to enhance tumor-specific therapy by optimizing various aspects, such as identifying the safest and most effective chemotherapy regimens, refining patient selection criteria, and improving perioperative care.

The impact of Paclitaxel-based hyperthermic intraperitoneal chemotherapy in advanced high-grade serous ovarian cancer patients - interim analysis of safety and immediate efficacy of a randomized control trial (C-HOC trial).

OBJECTIVE: This study evaluates the potential superiority of combining paclitaxel-based hyperthermic intraperitoneal chemotherapy (HIPEC) with sequential intravenous neoadjuvant chemotherapy over intravenous neoadjuvant chemotherapy alone in Chinese patients with Federation of Gynecology and Obstetrics (FIGO) stage IIIC, IVA and IVB high-grade serous ovarian/fallopian tube carcinoma (HGSOC). This interim analysis focuses on the safety and immediate efficacy of both regimens to determine the feasibility of the planned trial (C-HOC Trial). METHODS: In a single-center, open-label, randomized control trial, FIGO stage IIIC, IVA, and IVB HGSOC patients (FAGOTTI score ≥ 8 during laparoscopic exploration) unsuitable for optimal cytoreduction in primary debulking surgery (PDS) were randomized 2:1 during laparoscopic exploration. The Experiment Group (HIPEC Group) received one cycle of intraperitoneal neoadjuvant laparoscopic hyperthermic intraperitoneal chemotherapy (paclitaxel) followed by three cycles of intravenous chemotherapy (paclitaxel plus carboplatin), while the Control Group received only three cycles of intravenous chemotherapy. Both groups subsequently underwent interval debulking surgery (IDS). The adverse effects of chemotherapy, postoperative complications, and pathological chemotherapy response scores (CRS) after IDS were compared. RESULTS: Among 65 enrolled patients, 39 HIPEC Group and 21 Control Group patients underwent IDS. Grade 3-4 chemotherapy-related adverse effects were primarily hematological with no significant differences between the two groups. The HIPEC Group exhibited a higher proportion of CRS 3 (20.5% vs. 4.8%; P = 0.000). R0 resection rates in IDS were 69.2% (HIPEC Group) and 66.7% (Control Group). R2 resection occurred in 2.6% (HIPEC Group) and 14.3% (Control Group) cases. No reoperations or postoperative deaths were reported, and complications were managed conservatively. CONCLUSIONS: Combining HIPEC with IV NACT in treating ovarian cancer demonstrated safety and feasibility, with no increased chemotherapy-related adverse effects or postoperative complications. HIPEC improved tumor response to neoadjuvant chemotherapy, potentially enhancing progression-free survival (PFS). However, the final overall survival results are pending, determining if HIPEC combined with IV NACT is superior to IV NACT alone.

LAMN port-site metastasis after laparoscopic oophorectomy for a presumed ovarian tumour treated with CRS and HIPEC.

Low-grade appendiceal mucinous neoplasm (LAMN) may culminate as a mucin-secreting disease known as pseudomyxoma peritonei (PMP). Once the diagnosis of LAMN and PMP is made, cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS and HIPEC) are indicated.Herein, we present a female patient in her 50s who was diagnosed with an ovarian mass for which she underwent laparoscopic oophorectomy. As the pathology of the ovary showed a tumour of gastrointestinal origin, she then underwent CRS and HIPEC with a final pathology of LAMN. Six weeks later, a mucinous lesion confined to the abdominal wall was detected on a postoperative CT. Suspected for port-site metastasis at the laparoscopic trocar site, we treated this lesion using the same principles of treatment as the intra-abdominal disease. The abdominal wall mass was surgically resected, and the cavity created was irrigated with mitomycin C. On 30 months of follow-up, the patient had no evidence of disease.

Survival Difference of Endometrial Cancer Patients with Peritoneal Metastasis Receiving Cytoreductive Surgery (CRS) with and without Hyperthermic Intraperitoneal Chemotherapy (HIPEC): A Systematic Review and Meta-Analysis.

Although several studies have been completed to investigate the effect of cytoreductive surgery (CRS) with or without hyperthermic intraperitoneal chemotherapy (HIPEC) in endometrial cancer with peritoneal metastasis (ECPM), a direct comparison was not performed previously. A meta-analysis was performed to investigate the suspected additional survival benefits of CRS plus HIPEC over CRS only. Twenty-one and ten studies with a total number of 1116 and 152 cases investigating CRS only and CRS plus HIPEC were identified, respectively. When all articles were analyzed, the 1-year survival rate was 17.60% higher for CRS plus HIPEC (82.28% vs. 64.68%; p = 0.0102). The same tendency was observed for the 2-year (56.07% vs. 36.95%; difference: 19.12%; p = 0.0014), but not for the 5-year (21.88% vs. 16.45%; difference: 5.43%; p = 0.3918) survival rates. The same clinical significance, but statistically less strong observations, could be made if only the studies published after 2010 were investigated (1-year survival rate: 12.08% and p = 0.0648; 2-year survival rate: 10.90% and p = 0.0988). CRS remains one of the core elements of ECPM treatment, but the addition of HIPEC to CRS can increase the positive clinical outcome, especially in the first 2 years.

Efficacy of Hyperthermic Pressurized Intraperitoneal Aerosol Chemotherapy in an In Vitro Model Using a Human Gastric Cancer AGS Cell Line and an Abdominal Cavity Model.

PURPOSE: Peritoneal carcinomatosis (PC) presents a major challenge in the treatment of late-stage, solid tumors, with traditional therapies limited by poor drug penetration. We evaluated a novel hyperthermic pressurized intraperitoneal aerosol chemotherapy (HPIPAC) system using a human abdominal cavity model for its efficacy against AGS gastric cancer cells. MATERIALS AND METHODS: A model simulating the human abdominal cavity and AGS gastric cancer cell line cultured dishes were used to assess the efficacy of the HPIPAC system. Cell viability was measured to evaluate the impact of HPIPAC under 6 different conditions: heat alone, PIPAC with paclitaxel (PTX), PTX alone, normal saline (NS) alone, heat with NS, and HPIPAC with PTX. RESULTS: Results showed a significant reduction in cell viability with HPIPAC combined with PTX, indicating enhanced cytotoxic effects. Immediately after treatment, the average cell viability was 66.6%, which decreased to 49.2% after 48 hours and to a further 19.6% after 120 hours of incubation, demonstrating the sustained efficacy of the treatment. In contrast, control groups exhibited a recovery in cell viability; heat alone showed cell viability increasing from 90.8% to 94.4%, PIPAC with PTX from 82.7% to 89.7%, PTX only from 73.3% to 74.8%, NS only from 90.9% to 98.3%, and heat with NS from 74.4% to 84.7%. CONCLUSIONS: The HPIPAC system with PTX exhibits a promising approach in the treatment of PC in gastric cancer, significantly reducing cell viability. Despite certain limitations, this study highlights the system's potential to enhance treatment outcomes. Future efforts should focus on refining HPIPAC and validating its effectiveness in clinical settings.

Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy in the Management of Colorectal Cancer with Peritoneal Metastasis: A Single-Center Cohort Study.

Multimodal treatment in peritoneal metastases (PM) from colorectal neoplasms may improve overall survival (OS). In this study, we reported our experience in using cytoreductive surgery (CRS) combined with intraperitoneal chemohyperthermia (HIPEC) for the treatment of peritoneal metastases (PM) from colorectal neoplasms. The first aim was to evaluate the overall survival of these patients. Furthermore, using the results of the Prodige 7 Trial and incorporating them with the entropy balance statistical tool, we generated a pseudopopulation on which to test the use of CRS alone. We performed a retrospective analysis based on a prospective database of all 55 patients treated with CRS + HIPEC between March 2004 and January 2023. The median OS was 47 months, with 1-, 3- and 5-year survival rates of 90.8%, 58.7% and 42.7%, respectively. There was no significant difference in the data in the pseudogroup generated with entropy balance. This finding confirms the critical role of complete cytoreduction in achieving the best OS for patients with PM. PCI > 6 seems to be the most important prognostic factor influencing OS. At present, CRS + HIPEC seems to be the therapeutic strategy that guarantees the best results in terms of OS for patients with relatively low PCI and in whom a CCS ≤ 1 can be achieved.

Cytoreductive surgery without intra-peritoneal chemotherapy for metachronous colorectal peritoneal metastases.

BACKGROUND: Cytoreductive surgery and chemotherapy reportedly improve the prognosis of patients with metachronous peritoneal metastases. However, the types of peritoneal metastases indicated for cytoreductive surgery remains unclear. Therefore, we aimed to clarify the category of cases for which cytoreductive surgery would be effective and report the prognosis associated with cytoreductive surgery for metachronous peritoneal metastases. METHODS: This study included 52 consecutive patients who underwent cytoreductive surgery for metachronous peritoneal metastases caused by colorectal cancer between January 2005 and December 2018 and fulfilled the selection criteria. The median follow-up period was 54.9 months. Relapse-free survival was calculated as the time from cytoreductive surgery of metachronous peritoneal metastases to recurrence. Overall survival was defined as the time from cytoreductive surgery of metachronous peritoneal metastases to death or the end of the follow-up period. RESULTS: The 5-year relapse-free survival rate was 30.0% and the 5-year overall survival rate was 72.3%. None of the patients underwent hyperthermic intraperitoneal chemotherapy. The analysis indicated no potential risk factors for 5-year relapse-free survival. However, for 5-year overall survival, the multivariate analysis revealed that time to diagnosis of metachronous peritoneal metastases of < 2 years after primary surgery (hazard ratio = 4.1, 95% confidence interval = 2.0-8.6, p = 0.0002) and number of metachronous peritoneal metastases ≥ 3 (hazard ratio = 9.8, 95% confidence interval = 2.3-42.3, p = 0.002) as independent factors associated with a poor prognosis. CONCLUSIONS: Long intervals of more than 2 years after primary surgery and 2 or less metachronous peritoneal metastases were good selection criteria for cytoreductive surgery for metachronous peritoneal metastases from colorectal cancer.

Intraoperative urinary tract resection and construction in CRS + HIPEC procedures: a single center retrospective analysis.

INTRODUCTION: The safety and efficacy of CRS + HIPEC combined with urinary tract resection and reconstruction are controversial. This study aims to summarize the clinicopathological features and to evaluate the safety and survival prognosis of CRS + HIPEC combined with urinary tract resection and reconstruction. METHODS: The patients who underwent urinary tract resection and reconstruction as part of CRS surgery were retrospectively selected from our disease-specific database for analysis. The clinicopathological characteristics, treatment-related variables, perioperative adverse events (AEs), and survival outcomes were studied using a descriptive approach and the K-M analysis with log-rank comparison. RESULTS: Forty-nine patients were enrolled. Perioperative serious AEs (SAEs) were observed in 11 patients (22.4%), with urinary SAEs occurring in 3 patients (6.1%). Additionally, there were 23 cases (46.8%) involving urinary adverse events (UAEs). The median overall survival (OS) in the entire cohort was 59.2 (95%CI: 42.1-76.4) months. The median OS of the UAE group and No-UAE group were 59.2 months (95%CI not reached), and 50.5 (95%CI: 11.5 to 89.6) months, respectively, with no significant difference (P = 0.475). Furthermore, there were no significant differences in OS based on the grade of UAEs or the number of UAEs (P = 0.562 and P = 0.622, respectively). CONCLUSION: The combination of CRS + HIPEC with urinary tract resection and reconstruction is associated with a high incidence of Grade I-II UAEs, which do not have an impact on OS. The safety profile of this combined technique is acceptable. However, this is a retrospective single-center single-arm analysis, with limitations of generalizability and potential selection bias. The findings need high-level validation.

[Intraperitoneal chemotherapy for colorectal cancer peritoneal metastasis].

Peritoneal metastasis is one of the common site of colorectal cancer metastasis and associated with a poor prognosis. The core strategy for colorectal cancer peritoneal metastasis primarily revolves around a comprehensive treatment approach with cytoreductive surgery and systemic chemotherapy as the mainstay, supplemented by intraperitoneal chemotherapy. As an important supplement to treatment, intraperitoneal chemotherapy has broad application prospects. The main modalities are hyperthermic intraperitoneal chemotherapy (HIPEC), neoadjuvant intraperitoneal and systemic chemotherapy (NIPS), early postoperative intraperitoneal chemotherapy (EPIC), sequential postoperative intraperitoneal chemotherapy (SPIC), normothermic intraperitoneal chemotherapy (NIPEC) and pressurized intraperitoneal aerosol chemotherapy (PIPAC). To promote the standardized application of intraperitoneal chemotherapy, further research on the mechanisms underlying peritoneal metastasis of colorectal cancer, selection of effective intraperitoneal chemotherapy agents, determination of optimal timing and administration protocols, exploration of the feasibility of sequential intraperitoneal chemotherapy and conduction of valuable basic and clinical research are currently needed. This paper will review the development and origins of intraperitoneal chemotherapy, treatment modalities, as well as the current application status and prospects of various treatment approaches in the context of peritoneal metastasis of colorectal cancer.

First Clinical Safety and Feasibility Data of Whole-body Hyperthermia Pressurized Intraperitoneal Aerosol Chemotherapy (WBH-PIPAC) for Peritoneal Surface Malignancies.

BACKGROUND/AIM: This study evaluated the feasibility and safety of whole-body hyperthermia pressurized intraperitoneal aerosol chemotherapy (WBH-PIPAC) in patients with peritoneal surface malignancies. PATIENTS AND METHODS: This study retrospectively analyzed a database of 28 patients who had received one cycle of normothermic PIPAC prior to repetitive WBH-PIPACs. WBH (39-40°C) was induced using a Water-filtered infrared A device. Doxorubicin plus cisplatin or oxaliplatin was nebulized into a constant capnoperitoneum of 20 mmHg for 30 min at doses of 6.0 mg, 30.0 mg, or 120 mg per m2 body surface area, respectively. The primary outcome measures were feasibility and perioperative complications. RESULTS: The median age was 62 years (range=45-78 years). Primary tumor sites included the upper gastrointestinal tract (n=9), colon/rectum (n=7), hepato-pancreato-biliary system (n=3), peritoneum (n=2), ovaries (n=2), and unknown primary (n=5). The induction of WBH failed in one patient (6 liters ascites). After a median warming period of 95 min (53-117 min), the median rectal temperature (Trec) was 39.5°C (39.2-39.9°C). No hyperthermia-related side effects were observed. Twenty-seven patients received 50 WBH-PIPACs. The median time of therapeutic capnoperitoneum and treatment time with Trec ≥39°C was 39 min (37-43 min) and 66 min (53-69 min), respectively. The overall rate of postoperative procedure-related complications was 9/50, including seven grade I and two grade II complications. There were no grade III-V complications. CONCLUSION: In a highly selected group of patients, the feasibility and perioperative safety of WBH-PIPAC was comparable to normothermic PIPAC.

Omental metastases in patients with pseudomyxoma peritonei or colorectal peritoneal metastases - is routine omentectomy justified?

BACKGROUND: The greater omentum is routinely resected during cytoreductive surgery (CRS), but few studies have analyzed the rationale behind this. This study aimed to assess the prevalence of omental metastases (OM) and the correlation between macroscopically suspected and microscopically confirmed OM, in patients with pseudomyxoma peritonei (PMP) or colorectal peritoneal metastases (PM). METHOD: All patients without previous omentectomy, treated with initial CRS and hyperthermic intraperitoneal chemotherapy for PMP or colorectal PM, at Uppsala University Hospital in 2013-2021, were included. Macroscopic OM in surgical reports was compared with histopathological analyses. RESULTS: In all, 276 patients were included. In those with PMP, 112 (98%) underwent omentectomy and 67 (59%) had macroscopic suspicion of OM. In 5 (4%) patients, the surgeon was uncertain. Histopathology confirmed OM in 81 (72%). In patients with macroscopic suspicion, 96% had confirmed OM (positive predictive value, PPV). In patients with no suspicion, 24% had occult OM (negative predictive value, NPV = 76%). In patients with colorectal PM, 156 (96%) underwent omentectomy and 97 (60%) had macroscopic suspicion. For 5 (3%) patients, the surgeon was uncertain. OM was microscopically confirmed in 90 (58%). PPV was 85% and NPV was 89%. The presence of OM was a univariate risk factor for death in PMP (HR 3.62, 95%CI 1.08-12.1) and colorectal PM (HR 1.67, 95%CI 1.07-2.60), but not in multivariate analyses. CONCLUSION: OM was common and there was a high risk of missing occult OM in both PMP and colorectal PM. These results support the practice of routine omentectomy during CRS.

Hyperthermic intraperitoneal chemotherapy in colorectal cancer.

BACKGROUND: This study evaluated the efficacy of hyperthermic intraperitoneal chemotherapy (HIPEC) in colorectal cancer with peritoneal metastases (pmCRC) in a large international data set of patients. PATIENTS AND METHODS: Patients with pmCRC from 39 centres who underwent cytoreductive surgery with HIPEC between 1991 and 2018 were selected and compared for the HIPEC protocols received-oxaliplatin-HIPEC versus mitomycin-HIPEC. Following analysis of crude data, propensity-score matching (PSM) and Cox-proportional hazard modelling were performed. Outcomes of interest were overall survival (OS), recurrence-free survival (RFS) and the HIPEC dose-response effects (high versus low dose, dose intensification and double drug protocols) on OS, RFS and 90-day morbidity. Furthermore, the impact of the treatment time period was assessed. RESULTS: Of 2760 patients, 2093 patients were included. Median OS was 43 months (95% c.i. 41 to 46 months) with a median RFS of 12 months (95% c.i. 12 to 13 months). The oxaliplatin-HIPEC group had an OS of 47 months (95% c.i. 42 to 53 months) versus 39 months (95% c.i. 36 to 43 months) in the mitomycin-HIPEC group (P = 0.002), aHR 0.77, 95% c.i. 0.67 to 0.90, P < 0.001. The OS benefit persisted after PSM of the oxaliplatin-HIPEC group and mitomycin-HIPEC group (48 months (95% c.i. 42 to 59 months) versus 40 months (95% c.i. 37 to 44 months)), P < 0.001, aHR 0.78 (95% c.i. 0.65 to 0.94), P = 0.009. Similarly, matched RFS was significantly higher for oxaliplatin-HIPEC versus others (13 months (95% c.i. 12 to 15 months) versus 11 months (95% c.i. 10 to 12 months, P = 0.02)). High-dose mitomycin-HIPEC protocols had similar OS compared to oxaliplatin-HIPEC. HIPEC dose intensification within each protocol resulted in improved survival. Oxaliplatin + irinotecan-HIPEC resulted in the most improved OS (61 months (95% c.i. 51 to 101 months)). Ninety-day mortality in both crude and PSM analysis was worse for mitomycin-HIPEC. There was no change in treatment effect depending on the analysed time period. CONCLUSIONS: Oxaliplatin-based HIPEC provided better outcomes compared to mitomycin-based HIPEC. High-dose mitomycin-HIPEC was similar to oxaliplatin-HIPEC. The 90-day mortality difference favours the oxaliplatin-HIPEC group. A trend for dose-response between low- and high-dose HIPEC was reported.