The contemporary management of peritoneal metastasis: A journey from the cold past of treatment futility to a warm present and a bright future.

Peritoneal metastasis (PM) is often regarded as a less frequent pattern of spread; however, collectively across all spectra of primary tumors, the consequences of PM impact a large population of patients annually. Unlike other modes of metastasis, symptoms at presentation or during the treatment course are common, representing an additional challenge in the management of PM. Early efforts with chemotherapy and incomplete surgical interventions transiently improved symptoms, but durable symptom control and survival extension were rare, which established a perspective of treatment futility for PM through most of the 20th century. Notably, the continued development of better systemic therapy combinations, optimization of cytoreductive surgery (CRS), and rigorous investigation of combining regional therapy-specifically hyperthermic intraperitoneal chemotherapy-with CRS, have resulted in more effective multimodal treatment options for patients with PM. In this article, the authors provide a comprehensive review of the data establishing the contemporary approach for tumors with a high frequency of PM, including appendix, colorectal, mesothelioma, and gastric cancers. The authors also explore the emerging role of adding hyperthermic intraperitoneal chemotherapy to the well established paradigm of CRS and systemic therapy for advanced ovarian cancer, as well as the recent clinical trials identifying the efficacy of poly(adenosine diphosphate ribose) polymerase maintenance therapy. Finally, recent data are included that explore the role of precision medicine technology in PM management that, in the future, may help further improve patient selection, identify the best systemic therapy regimens, detect actionable mutations, and identify new targets for drug development.

Peritoneal metastases from gastric cancer in a nationwide cohort: Incidence, treatment and survival.

The aims of this study were to investigate incidence, risk factors and treatment of synchronous or metachronous peritoneal metastases (PM) from gastric cancer and to estimate survival of these patients using population-based data. Patients diagnosed with gastric cancer in 2015 to 2016 were selected from the Netherlands Cancer Registry. The incidence of synchronous and metachronous PM were calculated. Multivariable regression analyses were performed to identify factors associated with the occurrence of PM. Treatment and survival were compared between patients with synchronous and metachronous PM. Of 2206 patients with gastric cancer, 741 (34%) were diagnosed with PM. Of these, 498 (23%) had synchronous PM. The cumulative incidence of metachronous PM in patients who underwent potentially curative treatment (n = 675) was 22.8% at 3 years. A factor associated with synchronous and metachronous PM was diffuse type histology. Patients diagnosed with synchronous PM more often received systemic treatment than patients with metachronous PM (35% vs 18%, respectively, P < .001). Median overall survival was comparable between synchronous and metachronous PM (3.2 vs 2.3 months, respectively, P = .731). Approximately one third of all patients with gastric cancer are diagnosed with PM, either at primary diagnosis or during 3-year follow-up after potentially curative treatment. Patients with metachronous PM less often received systemic treatment than those with synchronous PM but survival was comparable between both groups. Future trials are warranted to detect gastric cancer at an earlier stage and to examine strategies that lower the risk of peritoneal dissemination. Also, specific treatment options for patients with gastric PM should be further investigated.

Metastasis-associated fibroblasts in peritoneal surface malignancies.

Over decades, peritoneal surface malignancies (PSMs) have been associated with limited treatment options and poor prognosis. However, advancements in perioperative systemic chemotherapy, cytoreductive surgery (CRS), and hyperthermic intraperitoneal chemotherapy (HIPEC) have significantly improved clinical outcomes. PSMs predominantly result from the spread of intra-abdominal neoplasia, which then form secondary peritoneal metastases. Colorectal, ovarian, and gastric cancers are the most common contributors. Despite diverse primary origins, the uniqueness of the peritoneum microenvironment shapes the common features of PSMs. Peritoneal metastization involves complex interactions between tumour cells and the peritoneal microenvironment. Fibroblasts play a crucial role, contributing to tumour development, progression, and therapy resistance. Peritoneal metastasis-associated fibroblasts (MAFs) in PSMs exhibit high heterogeneity. Single-cell RNA sequencing technology has revealed that immune-regulatory cancer-associated fibroblasts (iCAFs) seem to be the most prevalent subtype in PSMs. In addition, other major subtypes as myofibroblastic CAFs (myCAFs) and matrix CAFs (mCAFs) were frequently observed across PSMs studies. Peritoneal MAFs are suggested to originate from mesothelial cells, submesothelial fibroblasts, pericytes, endothelial cells, and omental-resident cells. This plasticity and heterogeneity of CAFs contribute to the complex microenvironment in PSMs, impacting treatment responses. Understanding these interactions is crucial for developing targeted and local therapies to improve PSMs patient outcomes.

Enhanced anti-tumor efficacy with multi-transgene armed mesenchymal stem cells for treating peritoneal carcinomatosis.

BACKGROUND: Mesenchymal stem cells (MSCs) have garnered significant interest for their tumor-tropic property, making them potential therapeutic delivery vehicles for cancer treatment. We have previously shown the significant anti-tumour activity in mice preclinical models and companion animals with naturally occurring cancers using non-virally engineered MSCs with a therapeutic transgene encoding cytosine deaminase and uracil phosphoribosyl transferase (CDUPRT) and green fluorescent protein (GFP). Clinical studies have shown improved response rate with combinatorial treatment of 5-fluorouracil and Interferon-beta (IFNb) in peritoneal carcinomatosis (PC). However, high systemic toxicities have limited the clinical use of such a regime. METHODS: In this study, we evaluated the feasibility of intraperitoneal administration of non-virally engineered MSCs to co-deliver CDUPRT/5-Flucytosine prodrug system and IFNb to potentially enhance the cGAS-STING signalling axis. Here, MSCs were engineered to express CDUPRT or CDUPRT-IFNb. Expression of CDUPRT and IFNb was confirmed by flow cytometry and ELISA, respectively. The anti-cancer efficacy of the engineered MSCs was evaluated in both in vitro and in vivo model. ES2, HT-29 and Colo-205 were cocultured with engineered MSCs at various ratio. The cell viability with or without 5-flucytosine was measured with MTS assay. To further compare the anti-cancer efficacy of the engineered MSCs, peritoneal carcinomatosis mouse model was established by intraperitoneal injection of luciferase expressing ES2 stable cells. The tumour burden was measured through bioluminescence tracking. RESULTS: Firstly, there was no changes in phenotypes of MSCs despite high expression of the transgene encoding CDUPRT and IFNb (CDUPRT-IFNb). Transwell migration assays and in-vivo tracking suggested the co-expression of multiple transgenes did not impact migratory capability of the MSCs. The superiority of CDUPRT-IFNb over CDUPRT expressing MSCs was demonstrated in ES2, HT-29 and Colo-205 in-vitro. Similar observations were observed in an intraperitoneal ES2 ovarian cancer xenograft model. The growth of tumor mass was inhibited by ~ 90% and 46% in the mice treated with MSCs expressing CDUPRT-IFNb or CDUPRT, respectively. CONCLUSIONS: Taken together, these results established the effectiveness of MSCs co-expressing CDUPRT and IFNb in controlling and targeting PC growth. This study lay the foundation for the development of clinical trial using multigene-armed MSCs for PC.

Top Peritoneal Surface Malignancy Articles from 2022 to Inform your Cancer Practice.

Over the last few decades, the role of cytoreductive surgery (CRS) with or without regional-based peritoneal therapies such as hyperthermic intraperitoneal chemotherapy (HIPEC) has evolved in the management of patients with peritoneal surface malignances (PSMs). Despite the benefit of CRS in improving oncologic outcomes, significant challenges remain in the treatment of patients with advanced PSMs, and the role of HIPEC continues to be questioned. Additionally, while there has been improvement in perioperative outcomes, long-term survival remains poor. As a result, there is much need to improve our understanding of the processes that drive tumor biology, thereby improving patient selection for various treatment approaches. Additionally, newer therapies are needed for patients who remain poor surgical candidates and who progress on systemic therapy. This article highlights recently published studies that we consider impactful in the care of patients with PSMs.

The 2022 PSOGI International Consensus on HIPEC Regimens for Peritoneal Malignancies: HIPEC Technologies.

This manuscript reports the results of an international consensus on technologies of hyperthermic intraperitoneal perioperative chemotherapy (HIPEC) performed with the following goals: To provide recommendations for the technological parameters to perform HIPEC. To identify the role of heat and its application forms in treating peritoneal metastases. To provide recommendations regarding the correct dosimetry of intraperitoneal chemotherapy drugs and their carrier solutions. To identify for each intraperitoneal chemotherapy regimen the best dosimetry and fractionation. To identify areas of future research pertaining to HIPEC technology and regimens. This consensus was performed by the Delphi technique and comprised two rounds of voting. In total, 96 of 102 eligible panelists replied to both Delphi rounds (94.1%) with a consensus of 39/51 questions on HIPEC technical aspects. Among the recommendations that met with the strongest consensus were those concerning the dose of HIPEC drug established in mg/m2, a target temperature of at least 42°C, and the use of at least three temperature probes to pursue hyperthermia. Ninety minutes as the ideal HIPEC duration seemed to make consensus. These results should be considered when designing new clinical trials in patients with peritoneal surface malignancies.

Actual 5-Year Survival After Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Patients with Peritoneal Carcinomatosis of Colorectal Origin.

BACKGROUND: Cytoreductive surgery and heated intraperitoneal chemotherapy (CRS/HIPEC) improves survival compared with chemotherapy alone in patients with peritoneal carcinomatosis (PC) of colorectal (CRC) origin, however, long-term survival data are lacking. We report the actual survival of patients who underwent CRS/HIPEC for PC of CRC origin with a minimum potential 5-year follow-up period to identify factors that preclude long-term survival. METHODS: We performed a retrospective analysis of a prospective database, analyzing patients undergoing CRS/HIPEC for PC of CRC origin from 2007 to 2017. Patients with aborted CRS/HIPEC, postoperative follow-up <90 days, or non-CRC histology were excluded. Overall survival (OS) and disease-free survival (DFS) were measured from date of surgery. Surviving patients with <60 months of follow-up were censored at date of last follow-up. RESULTS: A total of 103 patients met inclusion criteria and were analyzed. CC score 0-1 was achieved in 89.3% of patients, and median peritoneal cancer index (PCI) was 9 (interquartile range [IQR] 5-17). Ninety-day mortality was 2.9%. The median follow-up of survivors was 88 months. Five-year OS was 36%, and median OS was 42.5 months. Factors independently associated with poor survival included high PCI (PCI = 14-20, hazard ratio [HR] 3.1, p = 0.007, and PCI > 20, HR 5.3, p ≤ 0.001) and incomplete CRS (CC score-2, HR 2.96, p = 0.02). Patients with low PCI (0-6) had 5-year OS 60.7%. CONCLUSIONS: Actual 5-year OS was 36% and median OS was 42.5 months. Our study demonstrates that patients with PC from CRC origin with low PCI who undergo complete surgical resection can achieve favorable long-term survival.

The 2022 PSOGI International Consensus on HIPEC Regimens for Peritoneal Malignancies: Pseudomyxoma Peritonei.

BACKGROUND: The combination of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) constitutes the established standard of care for pseudomyxoma peritonei patients. However, the role of HIPEC lacks validation through randomized trials, leading to diverse proposed treatment protocols. This consensus seeks to standardize HIPEC regimens and identify research priorities for enhanced clarity. METHODS: The steering committee applied the patient, intervention, comparator, and outcome method to formulate crucial clinical questions. Evaluation of evidence followed the Grading of Recommendations, Assessment, Development, and Evaluation system. Consensus on HIPEC regimens and research priorities was sought through a two-round Delphi process involving international experts. RESULTS: Out of 90 eligible panelists, 71 (79%) participated in both Delphi rounds, resulting in a consensus on six out of seven questions related to HIPEC regimens. An overwhelming 84% positive consensus favored combining HIPEC with CRS, while a 70% weak positive consensus supported HIPEC after incomplete CRS. Specific HIPEC regimens also gained consensus, with 53% supporting Oxaliplatin 200 mg/m2 and 51% favoring the combination of cisplatin (CDDP) associated with mitomycin-C (MMC). High-dose MMC regimens received an 89% positive recommendation. In terms of research priorities, 61% of panelists highlighted the importance of studies comparing HIPEC regimens post CRS. The preferred regimens for such studies were the combination of CDDP/MMC and high-dose MMC. CONCLUSIONS: The consensus recommends the application of HIPEC following CRS based on the available evidence. The combination of CDDP/MMC and high-dose MMC regimens are endorsed for both current clinical practice and future research efforts.

Quality-of-Life Outcomes for Patients Taking Opioids and Psychotropic Medications Before Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy.

BACKGROUND: The impact of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) on quality of life (QoL) for patients taking opioids and psychotropic medications preoperatively is unclear. METHODS: This study retrospectively reviewed a CRS-HIPEC single-center prospectively maintained database for 2012-2016. Demographics and clinical data on opioids/psychotropic medication use were collected via chart review. The study collected QoL outcomes at baseline, then 3, 6, and 12 months postoperatively via the Center for Epidemiologic Studies Depression Scale (CES-D), Brief Pain Inventory, Functional Assessment of Cancer Therapy, and 36-Item Short-Form Health Survey. Differences in QoL between the groups were calculated using repeated measures analysis of variance regression. Descriptive statistics and Kaplan-Meier analyses were performed. RESULTS: Of 388 patients, 44.8% were taking opioids/psychotropic medications preoperatively. At baseline, those taking opioids/psychotropic medications preoperatively versus those not taking these medications had significantly worse QoL. By 1 year postoperatively, the QoL measures did not differ significantly except for emotional functioning (e.g., no medications vs. opioids/psychotropic medications: CES-D, 5.6 vs. 10.1). Median survival did not differ significantly (opioids/psychotropic medications vs. no medications: 52.3 vs. 60.6 months; p = 0.66). At 1 year after surgery, a greater percentage of patients were taking opioids, psychotropic medications, or both than at baseline (63.2% vs. 44.8%; p < 0.001). CONCLUSION: Despite worse baseline QoL, patients who took opioids/psychotropic medications had QoL scores 1 year postoperatively similar to the scores of those who did not except in the emotional domains. These data point to the potential utility of a timed psychosocial intervention to enhance emotional adaptation and further support the role of CRS-HIPEC in improving QoL.

Systematic Cholecystectomy During Cytoreductive Surgery Plus HIPEC: A Critical Analysis of an Empirical Tradition.

BACKGROUND: Some procedures performed during cytoreductive surgery (CRS) and hyperthermic intraoperative intraperitoneal chemotherapy (HIPEC) are based on empirical data. One of these procedures is systematic cholecystectomy. This study aimed to perform a critical analysis of the need for systematic cholecystectomy during CRS+HIPEC of patients with peritoneal carcinomatosis using long-term follow-up data. METHODS: Patients with peritoneal surface malignancies who were candidates for CRS+HIPEC and underwent surgery between January 2008 and December 2022 were analyzed. For patients with gallbladder involvement due to the disease or for patients whose preoperative study showed the presence of cholelithiasis, cholecystectomy was performed as part of the surgery, which was avoided for the remaining patients. All postoperative adverse events that occurred in the first 90 days were recorded, and clinical records focused on the development of biliary pathology during the follow-up period were studied. RESULTS: The results from a consecutive series of 443 patients with peritoneal surface malignancies who underwent surgery between January 2008 and December 2022 were analyzed. The average age of the cohort was 50 years. The median follow-up period for the cohort was 41 months (range, 12-180 months), with a disease-free survival of 17 months. For 373 of the patients, CRS+HIPEC was completed without an associated cholecystectomy, and in 16 of them, the appearance of cholelithiasis was detected during the follow-up period. Only two patients in the series showed complications derived from gallstones and required a delayed cholecystectomy. CONCLUSIONS: Although cholecystectomy is a safe procedure in the context of CRS+HIPEC, it is not risk free, and its routine performance may be unnecessary.

Adoption of an Enhanced Recovery After Surgery Protocol Increases Cost of Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy and Does not Improve Outcomes.

BACKGROUND: Enhanced recovery after surgery (ERAS) protocols have been shown to reduce length of stay (LOS) and complications. The impact of ERAS protocols on the cost of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) has not been studied. PATIENTS AND METHODS: We performed a retrospective cohort analysis of patients undergoing CRS-HIPEC from 2016-2022 at a single quaternary center. Propensity score matching was used to create pre-and post-ERAS cohorts. Cost, overall and serious complications, and intensive care unit (ICU) length of stay (LOS) between the two cohorts were compared using the Mann-Whitney U-test for continuous variables and χ2 test for categorical variables. RESULTS: Our final matched cohort consisted of 100 patients, with 50 patients in both the pre- and post-ERAS groups. After adjusting for patient complexity and inflation, the median total cost [$75,932 ($67,166-102,645) versus $92,992 ($80,720-116,710), p = 0.02] and operating room cost [$26,817 ($23,378-33,121) versus $34,434 ($28,085-$41,379), p < 0.001] were significantly higher in the post-ERAS cohort. Overall morbidity (n = 22, 44% versus n = 17, 34%, p = 0.40) and ICU length of stay [2 days (IQR 1-3) versus 2 days (IQR 1-4), p = 0.70] were similar between the two cohorts. A total cost increase of $22,393 [SE $13,047, 95% CI (-$3178 to $47,965), p = 0.086] was estimated after implementation of ERAS, with operating room cost significantly contributing to this increase [$8419, SE $1628, 95% CI ($5228-11,609), p < 0.001]. CONCLUSIONS: CRS-HIPEC ERAS protocols were associated with higher total costs due to increased operating room costs at a single institution. There was no significant difference in ICU LOS and complications after the implementation of the ERAS protocol.

Triphasic Learning Curve of Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy.

BACKGROUND: Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is an effective but costly procedure for select patients with peritoneal malignancies. The impact of progression along a learning curve on the cost of these procedures is unknown. PATIENTS AND METHODS: We performed a retrospective cohort study of patients undergoing CRS-HIPEC from 2016 to 2022 at a single quaternary center. Our study cohort was temporally divided into four equally sized volume quartiles (A, B, C, and D). We utilized cumulative sum plots and split-group analysis to characterize the institutional learning curve based on cost, operative time, length of stay, and morbidity. Multivariable linear regression was performed to estimate costs after adjusting for covariates. Bivariate analysis was performed using a Kruskal-Wallis test to compare continuous variables and a χ2 test to compare categorical variables. RESULTS: Of 201 patients, the median age [interquartile range (IQR)] was 57 (47-65) years, 113 (56%) patients were female, 143 (71%) were white, and 107 (53%) had private insurance. Median operating room charge [US$42,639 (US$32,477-54,872), p < 0.001] varied between volume quartiles, peaking in quartile C. Stabilization was achieved for 86 cases for operating room cost, 88 cases for routine cost, 96 cases for length of stay, 103 cases for operative time, 120 cases for intensive care unit length of stay, and 150 cases for overall and serious morbidity. The actual operating room and routine costs were similar to predicted costs at the end of the study period. CONCLUSIONS: The CRS-HIPEC learning curve is triphasic, with cost stability achieved relatively early compared with other markers of surgical proficiency.

Decision Regret in Patients with Appendiceal Cancer Undergoing Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy.

BACKGROUND: Decision regret is an emerging patient reported outcome. The aim of this study was to assess the incidence of regret in patients with appendiceal cancer (AC) who underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). PATIENTS AND METHODS: An anonymous survey was distributed to patients through the Appendix Cancer and Pseudomyxoma Peritonei (ACPMP) Research Foundation. The Decision Regret Scale (DRS) was employed, with DRS > 25 signifying regret. Patient demographics, tumor characteristics, postoperative outcomes, symptoms (FACT-C), and PROMIS-29 quality of life (QoL) scores were compared between patients who regretted or did not regret (NO-REG) the procedure. RESULTS: A total of 122 patients were analyzed. The vast majority had no regret about undergoing CRS-HIPEC (85.2%); 18 patients expressed regret (14.8%). Patients with higher regret had: income ≤ $74,062 (72.2% vs 44.2% NO-REG; p = 0.028), major complications within 30 days of surgery (55.6% vs 15.4% NO-REG; p < 0.001), > 30 days hospital stay (38.9% vs 4.8% NO-REG; p < 0.001), a new ostomy (27.8% vs 7.7% NO-REG; p = 0.03), >1 CRS-HIPEC procedure (56.3% vs 12.6% NO-REG; p < 0.001). Patients with worse FACT-C scores had more regret (p < 0.001). PROMIS-29 QOL scores were universally worse in patients with regret. Multivariable analysis demonstrated > 30 days in the hospital, new ostomy and worse gastrointestinal symptom scores were significantly associated with regret. CONCLUSIONS: The majority of patients with AC undergoing CRS-HIPEC do not regret undergoing the procedure. Lower income, postoperative complications, an ostomy, undergoing > 1 procedure, and with worse long-term gastrointestinal symptoms were associated with increased regret. Targeted perioperative psychological support and symptom management may assist to ameliorate regret.

Intra- and Interpatient Drug Response Heterogeneity Exist in Patients Undergoing Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy for Nongynecologic Cancers.

BACKGROUND: Select patients with peritoneal metastases are treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). We assayed for intra- and interpatient drug response heterogeneity through testing of patient-derived tumor organoids (PDTOs). METHODS: PDTOs were generated from CRS/HIPEC patients from December 2021 to September 2022 and subjected to an in vitro HIPEC drug screen. Drug response was assessed with a cell viability assay and cleaved caspase-3 staining. RESULTS: A total of 31 patients were consented for tissue collection. Viable tissue was harvested from 23, and PDTO generation was successful in 13 (56%). PDTOs were analyzed from six appendiceal, three colorectal, two small bowel, one gastric, and one adrenal tumor. Drug screen results were generated in as few as 7 days (62%), with an average time of 12 days. Most patients received mitomycin-C (MMC) intraoperatively (n = 9); however, in only three cases was this agent considered the optimal choice in vitro. Three sets of PDTOs were resistant (defined as > 50% PDTO viability) to all agents tested and two were pan-sensitive (defined as 3 or more agents with < 50% PDTO viability). In three patients, organoids were generated from multiple metastatic sites and intrapatient drug response heterogeneity was observed. CONCLUSIONS: Both intra- and interpatient drug response heterogeneity exist in patients undergoing CRS/HIPEC for nongynecologic abdominal cancers. Caution must be used when interpreting patient response to chemotherapeutic agents based on a single site of testing in those with metastatic disease.

Quality of Life After Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy (CRS/HIPEC): Cancer Survivors' Perspective Through In-Depth Interviews.

BACKGROUND: CRS/HIPEC patients face unique quality of life (QoL) challenges due to advanced disease (peritoneal carcinomatosis), the extent of procedure, and risk for long-term complications. Standard QoL questionnaires are generic, focusing on tumor type and standard treatments, and likely do not capture this select population's full experience, suggesting the need for tailored instruments. We aimed to characterize the QoL challenges faced by CRS/HIPEC cancer survivors and determine whether these were captured by a standard QoL questionnaire. PATIENTS AND METHODS: An anonymous, semi-structured individual interview was conducted with CRS/HIPEC patients addressing their experience at diagnosis, challenges related to CRS/HIPEC, and access to CRS/HIPEC information. Verbatim transcripts were interpreted using thematic analysis. Code and theme identification was inductive. Questions addressing common themes that were not encompassed by a standard QoL questionnaire were developed. RESULTS: We interviewed eight patients. Median age was 55 (range 30-71) years and 75% (n = 6) were women. Primary tumor sites included appendix (n = 4), ovarian (n = 3), and peritoneal mesothelioma (n = 1). Median time from CRS/HIPEC was 40.1 (range 3.1-216.3) months. Overall, 133 codes were identified and categorized into 9 themes. The most recurring were physical symptoms after CRS/HIPEC (specifically gastrointestinal symptoms), adjusting to survivorship, mental health, expectations from CRS/HIPEC, and access to care. A total of 22 questions that did not overlap with a standardized QoL questionnaire were developed. CONCLUSIONS: There is an unmet need to understand the unique QoL challenges CRS/HIPEC patients encounter. Patient-centered QoL questionnaires based on CRS/HIPEC patient experiences can capture these unique challenges and help guide future studies and care.

Towards Equal Access to Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy and Survival in Patients with Isolated Colorectal Peritoneal Metastases: A Nationwide Population-Based Study.

BACKGROUND: Before 2016, patients with isolated synchronous colorectal peritoneal metastases (PMCRC) diagnosed in expert centers had a higher odds of undergoing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) and better overall survival (OS) than those diagnosed in referring centers. Nationwide efforts were initiated to increase awareness and improve referral networks. METHODS: This nationwide study aimed to evaluate whether the between-center differences in odds of undergoing CRS-HIPEC and OS have reduced since these national efforts were initiated. All patients with isolated synchronous PMCRC diagnosed between 2009 and 2021 were identified from the Netherlands Cancer Registry. Associations between hospital of diagnosis and the odds of undergoing CRS-HIPEC, as well as OS, were assessed using multilevel multivariable regression analyses for two periods (2009-2015 and 2016-2021). RESULTS: In total, 3948 patients were included. The percentage of patients undergoing CRS-HIPEC increased from 17.2% in 2009-2015 (25.4% in expert centers, 16.5% in referring centers), to 23.4% in 2016-2021 (30.2% in expert centers, 22.6% in referring centers). In 2009-2015, compared with diagnosis in a referring center, diagnosis in a HIPEC center showed a higher odds of undergoing CRS-HIPEC (odds ratio [OR] 1.64, 95% confidence interval [CI] 1.02-2.67) and better survival (hazard ratio [HR] 0.80, 95% CI 0.66-0.96). In 2016-2021, there were no differences in the odds of undergoing CRS-HIPEC between patients diagnosed in HIPEC centers versus referring centers (OR 1.27, 95% CI 0.76-2.13) and survival (HR 1.00, 95% CI 0.76-1.32). CONCLUSION: Previously observed differences in odds of undergoing CRS-HIPEC were no longer present. Increased awareness and the harmonization of treatment for PMCRC may have contributed to equal access to care and a similar chance of survival at a national level.

Retrospective Evaluation of the Prognostic Value of Histological Growth Pattern in Patients with Colorectal Peritoneal Metastases Undergoing Curative-Intent Cytoreductive Surgery.

BACKGROUND: Two distinct histological growth patterns (HGPs) were described in patients with peritoneal metastasis of colorectal cancer origin (PMCRC) with limited Peritoneal Cancer Index (PCI) ≤ 6 who did not receive neoadjuvant chemotherapy (NAC) and were treated with cytoreductive surgery (CRS) ± hyperthermic intraperitoneal chemotherapy (HIPEC): pushing HGP (P-HGP) and infiltrating HGP (I-HGP). Patients with dominant P-HGP (> 50%) had significantly better disease-free survival (DFS) and overall survival (OS). OBJECTIVE: We aimed to determine whether these previous observations regarding the prognostic value of HGP in patients with PMCRC with low PCI (≤ 6) are also valid in all operable patients, regardless of whether they received NAC or not and regardless of PCI score. METHODS: This was a retrospective study including 76 patients who underwent complete CRS ± HIPEC for PMCRC between July 2012 and March 2019. In each patient, up to five of the largest excised peritoneal nodules were analyzed for their tumor-to-peritoneum interface. Correlations between NAC, HGP, and prognosis were further explored. RESULTS: Thirty-seven patients (49%) had dominant P-HGP and 39 (51%) had dominant I-HGP. On univariate analysis, patients with P-HGP ≤ 50% had significantly lower OS than those with dominant P-HGP > 50% (39 versus 60 months; p = 0.014) confirmed on multivariate analysis (hazard ratio 2.4, 95% confidence interval 1.3-4.5; p = 0.006). There were no significant associations between NAC and type of HGP. CONCLUSIONS: This study confirms the prognostic value and reproducibility of the two previously reported HGPs in PMCRC. Dominant P-HGP is associated with better DFS and OS in patients undergoing curative-intent CRS ± HIPEC compared with I-HGP, independently of the extent of peritoneal disease burden.

Initial Experience Using Laparoscopic HIPEC for Gastric Cancer with Peritoneal Metastasis: Safety and Outcomes.

BACKGROUND: Peritoneal metastases (PM) develop in approximately 20% of patients with gastric cancer (GC). For selected patients, treatment of PM with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) has shown promising results. This report aims to describe the safety and perioperative outcomes of laparoscopic HIPEC for GC/PM. METHODS: This retrospective cohort study evaluated patients who had GC and PM treated with laparoscopic HIPEC (2018-2022). The HIPEC involved cisplatin and mitomycin C (MMC) or MMC alone. The primary end point was perioperative safety. RESULTS: The 22 patients in this study underwent 27 procedures. The mean age was 58 ± 13 years. All the patients were Eastern Cooperative Oncology Group (ECOG) 0 or 1 (55 and 45%, respectively). Five patients underwent a second laparoscopic HIPEC, with a median of 126 days (interquartile range [IQR], 117-166 days) between procedures. The median peritoneal carcinomatosis index (PCI) was 4 (IQR, 2-9), and the median hospital stay was 2 days (IQR, 1-3 days). No 30-day readmissions or complications occurred. Eight patients (36%) underwent gastrectomy (CRS ± HIPEC). After an average follow-up period of 11 months, 7 (32%) of the 22 patients were alive. The median overall survival was 11 months (IQR, 195-739 days) from the initial procedure and 19.3 months (IQR, 431-1204 days) from the diagnosis. CONCLUSIONS: Laparoscopic HIPEC appears to be safe with minimal perioperative complications. Approximately one third of the patients undergoing initial laparoscopic HIPEC ultimately proceeded to cytoreduction and gastrectomy. Preliminary survival data from this highly selected cohort suggest that the addition of laparoscopic HIPEC to systemic chemotherapy does not compromise other treatment options. These initial results suggest that laparoscopic HIPEC may offer benefit to patients with GC and PM and aid in the selection of patients who may benefit from curative-intent resection.

Improved Postoperative Pain Management Outcomes After Implementation of Enhanced Recovery After Surgery (ERAS) Protocol for Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy (CRS-HIPEC).

BACKGROUND: Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) for patients with peritoneal carcinomatosis is promising but has potential for significant morbidity and prolonged hospitalization. Enhanced Recovery After Surgery (ERAS) is a standardized protocol designed to optimize perioperative care. This study describes trends in epidural and opioid use after implementing ERAS for CRS-HIPEC at a tertiary academic center. METHODS: A retrospective analysis of patients undergoing CRS-HIPEC from January 2020 to September 2023 was conducted. ERAS was implemented in February 2022. Medication and outcomes data were compared before and after ERAS initiation. All opioids were converted to morphine milligram equivalents (MMEs). RESULTS: A total of 136 patients underwent CRS-HIPEC: 73 (54%) pre- and 63 (46%) post-ERAS. Epidural usage increased from 63% pre-ERAS to 87% post-ERAS (p = 0.001). Compared with those without epidurals, patients with epidurals had decreased total 7-day oral and intravenous (IV) opioid requirements (45 MME vs. 316 MME; p < 0.001). There was no difference in 7-day opioid totals between pre- and post-ERAS groups. After ERAS, more patients achieved early ambulation (83% vs. 53%; p < 0.001), early diet initiation (81% vs. 25%; p < 0.001), and early return of bowel function (86% vs. 67%; p = 0.012). CONCLUSIONS: ERAS implementation for CRS-HIPEC was associated with increased epidural use, decreased oral and IV opioid use, and earlier bowel function return. Our study demonstrates that epidural analgesia provides adequate pain control while significantly decreasing oral and IV opioid use, which may promote gastrointestinal recovery postoperatively. These findings support the implementation of an ERAS protocol for effective pain management in patients undergoing CRS-HIPEC.

Negative Pressure Wound Therapy to Reduce Surgical Site Infections after CRS/HIPEC.

BACKGROUND: Surgical site infections (SSIs) are a common cause of morbidity after cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) for peritoneal malignancy. Negative pressure wound therapy (NPWT) has been proposed as a method to reduce the rates of SSIs; however, there is paucity in the literature on the efficacy in this population. The goal of this study was to determine whether routine use of NPWT in patients undergoing CRS/HIPEC could reduce the risk of developing SSI. METHODS: We performed a retrospective before-after study to assess the rates of SSI with NPWT compared with a standard postoperative surgical dressing (SSD) in all patients undergoing CRS/HIPEC from November 2013 to December 2021 at a single tertiary care center. The primary outcome was rate of SSI. A multivariate logistic regression analysis was performed to evaluate for risk factors for SSI. RESULTS: A total of 178 patients were treated with CRS/HIPEC over the study period. Seventy patients had placement of SSD, and 108 patients had placement of NPWT. Rates of SSI were 11.4% (8/70) and 5.6% (6/108) in the two groups, respectively (p = 0.16). On multivariate analysis, patients treated with NPWT had a significantly lower risk of developing an SSI (OR 0.24 [0.06, 0.92], p = 0.037). Patients living >50 km from the hospital had significantly higher risk of developing SSI (OR 2.03 [1.09, 3.78], p = 0.026). CONCLUSIONS: These results suggest that routine use of NPWT can reduce the risk of developing an SSI in patients undergoing CRS/HIPEC for peritoneal malignancy.