Approach to pseudomyxoma peritonei

Recurrence after cytoreductive surgery and HIPEC for pseudomyxoma peritonei: A single-center retrospective cohort study

BACKGROUND AND AIMS

Pseudomyxoma peritonei (PMP) is a rare disease characterized by progressive build-up of mucinous deposits inside the abdominal cavity. The aim of this study was to investigate the effect of disease recurrence on overall survival in patients with PMP after cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC).

METHODS

One-hundred thirty-two consecutive PMP patients treated with CRS + HIPEC at Helsinki University Hospital between 2008 and 2017 were included. The impact of clinicopathological and treatment-related characteristics on recurrence and overall survival was evaluated.

RESULTS

The median follow-up time in the study was 5.04 (range = 0.05-11.60) years. In 121 (91.7%) patients, the disease was classified as low grade and 11 (8.3%) had high-grade disease. In the low-grade group, 26 (21.5%) patients developed a recurrence during follow-up compared to 6 (54.5%) patients in the high-grade group. In the low-grade group, cumulative survival was 98.2%, 91.4%, and 91.4% at 3, 6, and 8 years, respectively. In the high-grade group, cumulative survival was 90.0% and 78.8% at 3 and 6 years, respectively. In patients with recurrent disease, the cumulative survival was 100%, 84.6%, and 84.6% at 3, 6, and 8 years in the low-grade category and 80.0% and 60.0% at 3 and 6 years in the high-grade category, respectively. In the low-grade group, a statistically significant correlation with recurrence but not with overall survival was identified with peritoneal cancer index (PCI), carcinoembryonic antigen (CEA), and the number of affected regions.

CONCLUSION

The recurrence of low-grade PMP does not significantly affect overall survival of patients. Disease extent may not be a prognostic indicator after curative CRS and HIPEC in low-grade PMP.

Analysis of causes and prognostic impact of tube occlusion during hyperthermic intraperitoneal chemotherapy for appendiceal pseudomyxoma peritonei

BACKGROUND

Appendiceal pseudomyxoma peritonei (PMP), a rare tumor from mucinous appendiceal origins, is treated with Cytoreductive Surgery (CRS) and Hyperthermic Intraperitoneal Chemotherapy (HIPEC). However, tubing blockages during HIPEC treatment pose a common challenge, impeding the smooth progression of therapy. Few studies to date have explored the incidence and risk factors of tube occlusion during HIPEC in patients with appendiceal PMP, as well as its adverse impact on postoperative complications.

METHODS

From October 2017 to June 2023, a total of 80 patients with appendiceal PMP undergoing combined CRS and HIPEC were included in this study. Tubing blockage events were strictly defined, with patients experiencing blockages during HIPEC treatment allocated to the study group, while those with unobstructed perfusion were assigned to the control group. A comparative analysis was conducted between the two groups regarding post-HIPEC health assessments and occurrence of complications. Risk factors for luminal occlusion during closed HIPEC procedures were identified through univariate and multivariate analysis of data from 303 HIPEC treatments.

RESULTS

Tubing blockages occurred in 41 patients (51.3%). The study group experienced prolonged gastrointestinal decompression time (4.1 ± 3.0 vs. 2.5 ± 1.7 days, P = 0.003) and prolonged time to bowel movement (6.1 ± 2.3 vs. 5.1 ± 1.8 days, P = 0.022) compared to the control group. There was no significant difference in the incidence of complications between the two groups. The 1-year survival rate postoperatively was 97%, and the 3-year survival rate was 81%, with no association found between tubing blockage and poorer survival. Additionally, In 303 instances of HIPEC treatment among these 80 patients, tube occlusion occurred in 89 cases (89/303, 29.4%). Multivariable logistic regression analysis revealed age, diabetes, hypertension, and pathology as independent risk factors for tube occlusion.

CONCLUSION

Tubing blockages are a common occurrence during HIPEC treatment, leading to prolonged postoperative gastrointestinal functional recovery time. When patients are elderly and have concomitant hypertension and diabetes, along with a histological type of low-grade mucinous tumor, the risk of tube occlusion increases. However, this study did not find a significant correlation between tubing blockage and the incidence of postoperative complications or overall patient survival.

Progress in Biological Research and Treatment of Pseudomyxoma Peritonei

Pseudomyxoma peritonei (PMP) is a rare disease characterized by extensive peritoneal implantation and mass secretion of mucus after primary mucinous tumors of the appendix or other organ ruptures. Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is currently the preferred treatment, with excellent efficacy and safety, and is associated with breakthrough progress in long-term disease control and prolonged survival. However, the high recurrence rate of PMP is the key challenge in its treatment, which limits the clinical application of multiple rounds of CRS-HIPEC and does not benefit from conventional systemic chemotherapy. Therefore, the development of alternative therapies for patients with refractory or relapsing PMP is critical. The literature related to PMP research progress and treatment was searched in the Web of Science, PubMed, and Google Scholar databases, and a literature review was conducted. The overview of the biological research, treatment status, potential therapeutic strategies, current research limitations, and future directions associated with PMP are presented, focuses on CRS-HIPEC therapy and alternative or combination therapy strategies, and emphasizes the clinical transformation prospects of potential therapeutic strategies such as mucolytic agents and targeted therapy. It provides a theoretical reference for the treatment of PMP and the main directions for future research.

A case of pseudomyxoma peritonei arising from a perforated intraductal papillary mucinous neoplasm that underwent cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

Pseudomyxoma peritonei (PMP) of pancreatic origin arising from an intraductal papillary mucinous neoplasm (IPMN) is rare. Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has been established as the optimal treatment for PMP. However, the benefits and safety of CRS with HIPEC for treating PMP of pancreatic origin remain unclear. Herein, we describe a case of PMP of pancreatic origin that was treated with CRS and HIPEC without postoperative complications. A 75-year-old woman was referred to our department. Computed tomography (CT) revealed a multilocular cystic tumor in the pancreatic tail, notable mucinous ascites in the abdominal cavity, and scalloping of the liver and spleen. CT did not reveal the appendix, and the ovaries were normal in size. The patient was diagnosed with PMP of pancreatic origin, and CRS and HIPEC were performed. Intraoperatively, the pancreatic tumor was perforated, and there was a large amount of mucinous ascites. We performed distal pancreatectomy in addition to CRS and HIPEC, with no intraoperative complications. The postoperative course was uneventful, and the patient survived after 6 months without recurrence. CRS with HIPEC may be a feasible treatment option for PMP of pancreatic origin.

Origin and survival outcomes of Pseudomyxoma peritonei-A retrospective study

BACKGROUND

Pseudomyxoma peritonei (PMP) is an unusual clinical condition typically presenting with widespread mucinous neoplastic lesions within the peritoneum resulting in gelatin material-rich ascites. It was first described by Werth in 1884. Ever since, its clinical presentation, definition, site of origin, and prognosis have been a subject of debate. However, many histopathologic, immunohistochemical, and genetic studies have attempted to locate the primary lesion in the appendix in both genders.

OBJECTIVES

To analyze the histological origin and survival outcomes of pseudomyxoma peritonei in patients treated at a regional cancer center.

MATERIALS AND METHODS

Fifteen cases of PMP were diagnosed during the five-year study period. The demographic and clinicopathological details were retrieved; the slides were reviewed and histological parameters reassessed. Descriptive statistics were used to express proportions. Continuous variables were recorded as mean (SD) or median (IQR). Kaplan-Meier (KM) curve was used to estimate overall survival.

RESULTS

Mean age for PMP was found to be 47.5 years for low grade Mucinous Carcinoma Peritonei (MCP), 54.2 years for high grade MCP, and 58 years for high grade MCP with signet ring cells. Most common overall presentation was abdominal distension in 53.3% (8/15) of cases, followed by acute appendicitis in 20% (3/15) cases. PMP was detected synchronous with the primary tumor in 9/15 cases (60%). Primary lesion in the appendix was grossly identified in 7/15 cases, while it was not explored in the remaining eight cases. Yet, by combined clinical, radiological, histopathological, and immunohistochemical analysis, we identified that most of the cases (14/15) had an appendiceal origin (93.3%). The overall survival for 12 months was 50% and for 18 months was 37%.

CONCLUSION

The surgeon and radiologist may well bear in mind the most common possibility of an appendiceal origin for PMP and resect the appendix, irrespective of the presence of a grossly or radiologically detectable lesions. We emphasize that immunohistochemistry helped to detect the site of origin even when the primary was occult.

Whole-Exome Sequencing Identifies Mutation Profile and Mutation Signature-Based Clustering Associated with Prognosis in Appendiceal Pseudomyxoma Peritonei

Pseudomyxoma peritonei (PMP) is a rare malignant clinical syndrome with little known about the global mutation profile. In this study, whole-exome sequencing (WES) was performed in 49 appendiceal PMP to investigate mutation profiles and mutation signatures. A total of 4,020 somatic mutations were detected, with a median mutation number of 56 (1-402). Tumor mutation burden (TMB) was generally low (median 1.55 mutations/Mb, 0.12-11.26 mutations/Mb). Mutations were mainly enriched in the function of cancer-related axonogenesis, extracellular matrix-related processes, calcium signaling pathway, and cAMP signaling pathway. Mutations in FCGBP, RBFOX1, SPEG, RTK-RAS, PI3K-AKT, and focal adhesion pathways were associated with high-grade mucinous carcinoma peritonei. These findings revealed distinct mutation profile in appendiceal PMP. Ten mutation signatures were identified, dividing patients into mutation signature cluster (MSC) 1 (N = 28, 57.1%) and MSC 2 (N = 21, 42.9%) groups. MSC (P = 0.007) was one of the four independent factors associated with 3-year survival. TMB (P = 0.003) and microsatellite instability (P = 0.002) were independent factors associated with MSC 2 grouping. Taken together, our findings provided a broader view in the understanding of molecular pathologic mechanism in appendiceal PMP and may be critical to developing an individualized approach to appendiceal PMP treatment.

IMPLICATIONS

This work describes exhaustive mutation profile of PMP based on WES data and derives ten mutation signatures, which divides patients into two clusters and serve as an independent prognostic factor associated with 3-year survival.

Analysis of the characteristics and outcomes of patients with pseudomyxoma peritonei of appendiceal origin treated with curative-intent surgery

BACKGROUND

There are no previous studies on pseudomyxoma peritonei regarding the details of surgical procedures included in cytoreductive surgery and quantitative evaluation for peritoneal metastases by region in the abdominal cavity. This study aimed to describe the characteristics and procedural details involved in cytoreductive surgery, and survival outcomes of patients with pseudomyxoma peritonei originating from appendiceal mucinous neoplasm, and identify differences in the difficulty of cytoreductive surgery based on tumor location.

METHODS

Patient characteristics and survival outcomes were studied through a retrospective review. The complete cytoreduction rate (i), the 5-year survival rate for patients with complete cytoreduction (ii), and an index as a complement (i × ii × 100) were described for patients who had tumors larger than 50 mm in one of the 13 regions of the abdominal cavity.

RESULTS

A total of 989 patients were treated with curative-intent cytoreductive surgery. The median peritoneal cancer index was 18 (interquartile range, 6-29), with complete cytoreduction achieved in 702 patients (71%); the major complication rate was 17%. The median overall survival was 92.9 months, compared to 53.8 months for patients who underwent total gastrectomy and 30.4 months for those who underwent total colectomy. In the 13 abdominal regions, the index scores indicating cytoreduction difficulty were categorized into three risk groups: upper and mid-abdominal (>20), lateral abdominal (10-20), and small bowel (<10).

CONCLUSIONS

Cytoreductive surgery offered favorable survival outcomes, even in cases involving total gastrectomy. The difficulty of achieving complete cytoreduction varied across abdominal regions and was classified into three levels.

Long-term survival in patients with PMP: a single-institutional retrospective study from China

BACKGROUND

As the standard treatment for pseudomyxoma peritonei (PMP), cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) can significantly prolong the survival of PMP patients, and some patients can even achieve long-term survival (LTS) or clinical cure. The purpose of this study was to analyze the clinicopathological and treatment features of PMP patients with LTS and to explore the survival benefit factors of PMP patients.

METHODS

The clinicopathological and prognostic data of PMP patients who received CRS + HIPEC at our center from December 2004 to May 2023 were retrospectively analyzed. PMP patients were divided into LTS group (≥ 10 years) and short-term survival (STS) group (< 5 years) according to the length of natural history. Univariate and multivariate analyses were performed to explore the beneficial factors of PMP patients with LTS.

RESULTS

A total of 609 patients with PMP received CRS + HIPEC treatment at our center. Two-hundred one patients with PMP were included in the study after screening, including 39 patients (19.4%) in the LTS group and 162 patients (80.6%) in the STS group. In STS group and LTS group, median overall survival based on natural history was 29.2 (2.4-59.9) vs. 138.9 (120.3-416.7) months. Univariate analysis revealed 8 factors (P < 0.05) with statistically significant differences between the two groups: gender, chemotherapy history, previous surgical score, Karnofsky Performance Status score, pathological diagnosis, lymphatic metastasis, peritoneal cancer index, and completeness of cytoreduction (CC). Multivariate analysis identified only two factors independently associated with LTS of PMP patients: CC and pathological diagnosis.

CONCLUSION

Complete CRS and pathological features are two key factors affecting LTS in PMP patients.

Current Evidence for the Use of HIPEC and Cytoreductive Surgery in Gastric Cancer Metastatic to the Peritoneum

Gastric cancer (GCa) is an aggressive malignancy, representing the third leading cause of cancer mortality worldwide. The poor prognosis of GCa can be associated with the prevalence of peritoneal metastasis (PM). Current international and national GCa treatment guidelines only recommend palliative treatment options for patients with PM. Since the 1980s there have been multiple single arm trials, randomized controlled trials, and metanalysis investigating the use of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with advanced GCa, with or without PM. Results from these studies have been encouraging, with some large-volume centers even incorporating HIPEC into their treatment algorithms for patients with advanced GCa. Additionally, there are several ongoing trials that, when completed, will increase our understanding of the efficacy of CRS & HIPEC in patients with GCa metastatic to the peritoneum. Herein we review the current evidence, ongoing trials, consensus guidelines, and future considerations regarding the use of CRS & HIPEC in patients suffering from GCa with PM.

Appendiceal Mucinous Neoplasms: From Clinic to Pathology and Prognosis

Appendiceal mucinous neoplasms have been classified differently over time causing confusion when comparing results between working groups in this field and establishing a prognosis of the disease. A historical perspective of the different classification systems of these tumors is essential for the understanding of the evolution of concepts and histopathological definitions that have led up to the present moment. We carried out a systematic review of the pathological classifications of appendiceal mucinous tumors and how they have included the new criteria resulting from clinical and pathological research. The latest classifications by PSOGI and AJCC 8th edition Cancer Staging have made a great effort to incorporate the new pathological descriptions and develop prognostic groups. The introduction of these new classification systems has posed the challenge of verifying how they adapt to our casuistry and which one defines best the prognosis of our patients. We reclassified our series of patients treated for mucinous appendiceal tumors with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy following the PSOGI and the AJCC 8th edition criteria and concluded that both classifications correspond well with the OS and DFS of these patients, with some advantage relative to the PSOGI classification due to a better histopathological description of the different groups.

Diagnostic and Therapeutic Algorithm for Appendiceal Tumors and Pseudomyxoma Peritonei: A Consensus of the Peritoneal Malignancies Oncoteam of the Italian Society of Surgical Oncology (SICO)

Aim: Pseudomyxoma peritonei (PMP) is an uncommon pathology, and its rarity causes a lack of scientific evidence, precluding the design of a prospective trial. A diagnostic and therapeutic algorithm (DTA) is necessary in order to standardize the disease treatment while balancing optimal patient management and the correct use of resources. The Consensus of the Italian Society of Surgical Oncology (SICO) Oncoteam aims at defining a diagnostic and therapeutic pathway for PMP and appendiceal primary tumors applicable in Italian healthcare. Method: The consensus panel included 10 delegated representatives of oncological referral centers for Peritoneal Surface Malignancies (PSM) affiliated to the SICO PSM Oncoteam. A list of statements regarding the DTA of patients with PMP was prepared according to recommendations based on the review of the literature and expert opinion. Results: A consensus was obtained on 33 of the 34 statements linked to the DTA; two flowcharts regarding the management of primary appendiceal cancer and peritoneal disease were approved. Conclusion: Currently, consensus has been reached on pathological classification, preoperative evaluation, cytoreductive surgery technical detail, and systemic treatment; some controversies still exist regarding the exclusion criteria for HIPEC treatment. A shared Italian model of DTA is an essential tool to ensure the appropriateness and equity of treatment for these patients.

Effect of standardized fluid management on cardiac function after CRS + HIPEC in patients with PMP: a single-center case-control study

OBJECTIVE

To investigate the effects of standardized fluid management (SFM) on cardiac function in patients with pseudomyxoma peritonei (PMP) after cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).

METHOD

Patients with PMP who underwent CRS + HIPEC at our center were retrospectively analyzed. The patients were divided into control and study groups according to whether SFM was applied after CRS + HIPEC. We compared the preoperative and postoperative cardiac and renal function parameters, daily fluid volume three days after CRS, and cardiovascular-related adverse events. Univariate and multivariate analyses were performed to identify the indicators affecting clinical prognosis.

RESULT

Among the 104 patients, 42 (40.4%) were in the control group and 62 (59.6%) in the study group. There were no statistically significant differences between the two groups in the main clinicopathological characteristics, preoperative cardiac and renal function parameters, and CRS + HIPEC-related indicators. The incidences of cardiac troponin I (CTNI) > upper limit of normal (ULN), >2 × ULN, >3 × ULN, serum creatinine > ULN, and blood urea nitrogen > ULN were higher in the control group than in the study group (p < 0.05). The median daily fluid volume of the control group was higher than that of the study group 3 days after CRS (p < 0.05). Postoperative CTNI > 2 × ULN was an independent risk factor for serious circulatory adverse events. Survival analysis revealed pathological grading, completeness of cytoreduction score, and postoperative CTNI > ULN as independent prognostic factors.

CONCLUSIONS

SFM after CRS + HIPEC in patients with PMP may reduce cardiovascular adverse events risk and improve clinical outcomes.

Long-Term Treatment of Unresectable Pseudomyxoma Peritonei with Multiple Treatments of Intratumoural Bromelain and Acetylcysteine (BromAc®): A Case Report

Pseudomyxoma peritonei is a rare peritoneal malignancy characterized by the progressive accumulation of mucinous material and tumour within the abdomen and pelvis. Percutaneous drainage of mucin may be a non-surgical option for relief of symptoms; however, it remains difficult due to the high viscosity of mucin, with numerous case reports reporting difficulty removing material through medium-bore catheters alone. BromAc is a therapy currently undergoing development which dissolves mucinous tumour masses and allows for extraction. This report describes the case of a patient who has had multiple treatments with BromAc over 4 years.

Survival prediction by Bayesian network modeling for pseudomyxoma peritonei after cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy

OBJECTIVES

To establish a survival prognostic model for pseudomyxoma peritonei (PMP) treated with cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC) based on Bayesian network (BN).

METHODS

453 PMP patients were included from the database at our center. The dataset was divided into a training set to establish BN model and a testing set to perform internal validation at a ratio of 8:2. From the training set, univariate and multivariate analyses were performed to identify independent prognostic factors for BN model construction. The confusion matrix, receiver operating characteristic (ROC) curve and the area under curve (AUC) were used to evaluate the performance of the BN model.

RESULTS

The univariate and multivariate analyses identified 7 independent prognostic factors: gender, previous operation history, histological grading, lymphatic metastasis, peritoneal cancer index, completeness of cytoreduction and splenectomy (all p < 0.05). Based on independent factors, the BN model of training set was established. After internal validation, the accuracy and AUC of the BN model were 70.3% and 73.5%, respectively.

CONCLUSION

The BN model provides a reasonable level of predictive performance for PMP patients undergoing CRS + HIPEC.

A proposal for changing nomenclature from pseudomyxoma peritonei (PMP) to abdomino-peritoneal mucinous carcinoma (APM) based on its long journey and experience from tertiary oncology center in India

Introduction

Pseudomyxoma peritonei (PMP) is a generalized term, usually known as “jelly belly” since 1884. Incidence is very low, 1–3 per million people per year. Because of its indolent nature, it is usually diagnosed at an advanced stage, thereby impacting the quality of life. The 5-year survival rate varies from 23 to 86% in world literature. Even 10 years and 20 years of survival have been described. With our experience, we like to propose rename of PMP as abdomino-peritoneal mucinous carcinoma (APM) as we strongly feel the time has come to specify the term and standardize the management strategy.

Methodology

In the premier institute of India and as a tertiary referral center, we experienced the maximum number of advanced cases of APM. From 2012 to 2021, we analyzed all the APM patients based on a prospectively maintained computerized database in the department of surgical oncology and found the reasons for renaming from this traditional one.

Results

We included a total of 87 patients who underwent surgical intervention. Thirty-five patients underwent cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC), and 52 patients underwent debulking. In CRS-HIPEC patients, CC-0 was achieved in 28 patients (80%), CC-1 in 4 patients (11.4%), and CC-2 in 3 patients (8.6%). Palliative intent HIPEC was done in 3 patients (8.6%). Clavien-Dindo grade III and IV morbidity was observed in 18.8% of patients with 90 days mortality of 5.7%.

Conclusion

With our long-term experience and advancement of scientific evidence, we like to propose a new name for PMP as APM. We strongly believe this paper will give a clear picture of this rare disease and standard management outlines.

PET-CT in Clinical Adult Oncology: III. Gastrointestinal Malignancies

Simple Summary

Positron emission tomography (PET), typically combined with computed tomography (CT), has become a critical advanced imaging technique in oncology. With PET-CT, a radioactive molecule (radiotracer) is injected in the bloodstream and localizes to sites of tumor because of specific cellular features of the tumor that accumulate the targeting radiotracer. The CT scan, performed at the same time, provides information to facilitate the characterization of radioactivity from deep or dense structures, and to provide detailed anatomic information. PET-CT has a variety of applications in oncology, including staging, therapeutic response assessment, restaging and surveillance. This series of six review articles provides an overview of the value, applications, and imaging interpretive strategies of PET-CT in the more common adult malignancies. The third report in this series provides a review of PET-CT imaging in gastrointestinal malignancies.

Abstract

PET-CT is an advanced imaging modality with many oncologic applications, including staging, assessment of response to therapy, restaging and longitudinal surveillance for recurrence. The goal of this series of six review articles is to provide practical information to providers and imaging professionals regarding the best use of PET-CT for specific oncologic indications, and the potential pitfalls and nuances that characterize these applications. In the third of these review articles, key tumor-specific clinical information and representative PET-CT images are provided to outline the role that PET-CT plays in the management of patients with gastrointestinal malignancies. The focus is on the use of ¹⁸F fluorodeoxyglucose (FDG), rather than on research radiopharmaceuticals under development. Many different types of gastrointestinal tumors exist, both pediatric and adult. A discussion of the role of FDG PET-CT for all of these is beyond the scope of this review. Rather, this article focuses on the most common adult gastrointestinal malignancies that may be encountered in clinical practice. The information provided here will provide information outlining the appropriate role of PET-CT in the clinical management of patients with gastrointestinal malignancies for healthcare professionals caring for adult cancer patients. It also addresses the nuances and provides interpretive guidance related to PET-CT for imaging providers, including radiologists, nuclear medicine physicians and their trainees.

Comprehensive Understanding and Evolutional Therapeutic Schemes for Pseudomyxoma Peritonei: A Literature Review

Pseudomyxoma peritonei is an infrequent solid tumor in clinical practice. The low morbidity and deficient understanding of this mucus-secreting malignant disease increase the risks of delayed identification or uncontrollable deterioration. In quite a lot cases, patients go through complete cytoreduction surgery and hyperthermic intraperitoneal chemotherapy could receive a long time survival over 5 years. But the recurrence rate is also hard to overlook. Unlike other types of cancer, the standard treatment for this considerable groups has not been confirmed yet. With the advanced medical progression, studies have been carrying out based on pathogenesis, biological characters, and mutated gene location. All but a few get statistical survival benefits, let alone the breaking progress on research or therapeutic practice in the field. We try to give a comprehensive exposition of pseudomyxoma peritonei around the epidemiology, radiologic features, clinical manifestation, present treatment and promising schemes, hoping to arise much attention and reflection on the feasible solutions, especially for the recrudescent part.

Radiomics analysis based on CT's greater omental caking for predicting pathological grading of pseudomyxoma peritonei

The objective of this study was to predict the preoperative pathological grading and survival period of Pseudomyxoma peritonei (PMP) by establishing models, including a radiomics model with greater omental caking as the imaging observation index, a clinical model including clinical indexes, and a combined model of these two. A total of 88 PMP patients were selected. Clinical data of patients, including age, sex, preoperative serum tumor markers [CEA, CA125, and CA199], survival time, and preoperative computed tomography (CT) images were analyzed. Three models (clinical model, radiomics model and combined model) were used to predict PMP pathological grading. The models’ diagnostic efficiency was compared and analyzed by building the receiver operating characteristic (ROC) curve. Simultaneously, the impact of PMP’s different pathological grades was evaluated. The results showed that the radiomics model based on the CT’s greater omental caking, an area under the ROC curve ([AUC] = 0.878), and the combined model (AUC = 0.899) had diagnostic power for determining PMP pathological grading. The imaging radiomics model based on CT greater omental caking can be used to predict PMP pathological grading, which is important in the treatment selection method and prognosis assessment.

Indication of Hyperthermic Intraperitoneal Chemotherapy in Gastric Cancer (Gastripec, Gastrichip)

<b><i>Background:</i></b> Gastric cancer (GC) is associated with a poor prognosis mostly due to peritoneal metastasis, which will develop in time during the patient’s disease history. To prevent and treat peritoneal metastasis, different kinds of treatment regimens have been described. <b><i>Summary:</i></b> In this review, we addressed two main topics – prophylaxis and treatment of peritoneal metastasis in GC. Prevention should be directed towards diminishing cancer cell spillage and reducing adherence of cancer cells to the abdominal cavity. Postoperative washing of the abdomen with or without chemotherapy and additional heat are herein discussed. <b><i>Key Messages:</i></b> Treatment of existing peritoneal metastasis is effective in patients with limited disease and tumour spread. Cytoreductive surgery including resection of peritoneal metastasis followed directly with hyperthermic intraperitoneal chemotherapy can increase overall survival and progression-free survival in selected patients. Drugs, duration and time schedules of intraperitoneal chemotherapy are reviewed and presented. Intraperitoneal chemotherapy seems to improve the prognosis of patients with GC and peritoneal metastasis after complete resection of both primary and metastatic tumours.

Disparities in the Management of Peritoneal Surface Malignancies

Peritoneal surface malignancies are a group of aggressive cancers involving the peritoneum. Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy can improve outcomes and survival in select patients. Despite significant advancements in care, racial disparities in peritoneal malignancy outcomes persist and may have even worsened over time. Poor adherence to guideline-recommended therapy introduces wide variability in patient care and often results in fewer options and suboptimal treatment of vulnerable populations. This review explores biological, sociodemographic, and environmental factors that contribute to disparities in peritoneal malignancy outcomes.

Pseudomyxoma peritonei originating from intestinal duplication: A case report and review of the literature

BACKGROUND

Pseudomyxoma peritonei (PMP) is a rare mucinous neoplasm with a relatively low incidence of 1 to 2 per million individuals. It is typically characterized by a type of gelatinous ascites named “jelly belly”. Most cases of PMP occur in association with ruptured primary mucinous tumors of the appendix (90%). Periodically, PMP can originate from mucinous carcinomas at other sites, including the colorectum, gallbladder, and pancreas. However, unusual origin can occur, as noted in this case report.

CASE SUMMARY

A 52-year-old woman had an unusual derivation of PMP from intestinal duplication. The patient complained of abdominal distension and increasing abdominal girth. Abdominal contrast-enhanced computed tomography showed a mass in the greater omentum located on the left side of the abdomen, likely to be a cystic mass of peritoneal origin. A PMP diagnosis was presumed based on the specific signs of the mass with flocculent and stripe-like echoes in ultrasound images. Ultrasound-guided percutaneous aspiration suggested a high likelihood of PMP. Once the PMP diagnosis was recognized, identification of the origin of the primary tumor was indicated. Thus, an exploratory laparoscopy was performed. In the absence of a primary tumor of appendix origin, the diagnosis of a low-grade mucinous neoplasm of intestinal duplication origin was finally confirmed by histopathology.

CONCLUSION

PMP is secondary to mucinous carcinomas of the appendix mostly. This case resulted from an unusual derivation from intestinal duplication.

Synthesis of benzoxazole-based vorinostat analogs and their antiproliferative activity

Hydroxamic acid derivatives constitute an interesting novel class of antitumor agents. Three of them, including vorinostat, are approved drugs for the treatment of malignancies, while several others are currently under clinical trials. In this work, we present new vorinostat analogs containing the benzoxazole ring as the cap group and various linkers. The benzoxazole-based analogs were synthesized starting either from 2-aminobenzoxazole, through conventional coupling, or from benzoxazole, through a metal-free oxidative amination. All the synthesized compounds were evaluated for their antiproliferative activity on three diverse human cancer cell lines (A549, Caco-2 and SF268), in comparison to vorinostat. Compound 12 (GK601), carrying a benzoxazole ring replacement for the phenyl ring of vorinostat, was the most potent inhibitor of the growth of three cell lines (IC₅₀ 1.2-2.1 μΜ), similar in potency to vorinostat. Compound 12 also inhibited human HDAC1, HDAC2 and HDAC6 like vorinostat. This new analog also showed antiproliferative activity against two colon cancer cell lines genetically resembling pseudomyxoma peritonei (PMP), namely HCT116 GNAS R201C/+ and LS174T (IC₅₀ 0.6 and 1.4 μΜ, respectively) with potency comparable to vorinostat (IC₅₀ 1.1 and 2.1 μΜ, respectively).

Ki67 does not predict recurrence for low-grade appendiceal mucinous neoplasms with peritoneal dissemination after cytoreductive surgery and HIPEC

Low-grade appendiceal mucinous neoplasms (LAMN) can disseminate to become low-grade mucinous carcinoma peritonei (LGMCP), which is optimally treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). Approximately half of the patients with LGMCP recur despite complete cytoreduction, and risk factors for recurrence are poorly understood. We sought to evaluate if Ki67 predicts progression of LGMCP after CRS/HIPEC. A retrospective review of a prospectively maintained database was performed to identify patients treated with complete CRS/HIPEC for LGMCP from 2008 to 2019 with Ki67 assessed. Patient characteristics, histologic data, average and focally high "hotspot") Ki67 index, progression-free survival (PFS), and overall survival (OS) were analyzed. Ki-67 immunostain was performed on the histologic section with the highest cellularity and architectural complexity. Forty-four patients with LGMCP (55% male, median age 61) were identified. The median Ki67 score and hotspot Ki67 score was 15% (1-70) and 50% (1-90), respectively. On univariate analysis, average Ki67 and hotspot Ki67 were not predictive of PFS when analyzed as continuous normalized values (HR 1.0, p = 0.79 and HR 1.1, p = 0.38, respectively) or as categorical values when stratified by the median (HR 0.9, p = 0.67 and HR 1.0, p = 0.93). This remained true on multivariate analysis when stratified for peritoneal cancer index, CEA, and completeness of cytoreduction score for both normalized Ki67 and hotspot Ki67 (HR 0.9 [95% CI 0.8-1.3], p = 0.94 and HR 1.04 [95% CI 0.8-1.3], p = 0.73, respectively). Ki67 failed to predict disease recurrence for patients with LGMCP in this cohort.

Novel Use of Bromelain and Acetylcysteine (BromAc®) for Pleural Involvement in Pseudomyxoma Peritonei

Pseudomyxoma peritonei (PMP) is a rare mucinous disease most commonly arising from the appendix. Pleural involvement arising from established PMP is seen in a small number of cases. Combined cytoreductive surgery and hyperthermic intrathoracic chemotherapy is the treatment of choice when managing intra-thoracic PMP. In cases of recurrence, surgical intervention may be technically challenging and carry higher rates of complications, morbidity, and mortality. Bromelain and acetylcysteine (BromAc^®) is a novel treatment modality that has demonstrated mucolytic properties. When injected directly into mucinous disease, it facilitates tumour dissolution and allows it to be aspirated. It has recently been tested in the treatment of inoperable peritoneal mucinous disease, with an acceptable safety profile and positive objective response. Here we describe the first two cases of BromAc^® administered directly into pleural adenomucinosis, with striking differences in response between the two patients likely due to differences in tumour hardness.

Intraoperative photodynamic therapy and hyperthermic intraperitoneal chemotherapy in cytoreductive treatment of patients with disseminated mucinous carcinoma of appendix

The article presents the experience of surgical treatment of 57 patients with peritoneal pseudomyxoma of appendicular genesis. In 32 (56.1%) patients, the operation was supplemented with intraoperative photodynamic therapy (IOPDT). In the other 25 (43.9%) patients, hyperthermic intraperitoneal chemotherapy (HIPEC) was performed. The analysis according to the value of the peritoneal carcinomatosis index, completeness of cytoreduction, the volume of operations performed, postoperative complications and hospital mortality, as well as long-term treat- ment results in two groups is presented. It was shown that with significantly worse results in terms of cytoreduction completeness obtained in the IOPDT group compared to the HIPEC group, the 5-year survival rate in the HIPEC group was 86.6%, with IOPDT - 65.2%. At the same time, in the IOPDT group, the rate of postoperative complications was significantly lower (11.1%), and there was no mortality; in the HIPEC group, these indicators were 23.8% and 12.0%, respectively. The results obtained indicate that the IOPDT method is an effective and promising direction in the surgical treatment of peritoneal pseudomyxoma.

Evidence-Based Strategies for the Treatment of Peritoneal Malignancies during Health Care Resource Restriction: The COVID-19 Pandemic

Background: The COVID-19 pandemic has put enormous pressure on hospital resources, and has affected all aspects of patient care. As operative volumes decrease, cancer surgeries must be triaged and prioritized with careful thought and attention to ensure maximal benefit for the maximum number of patients. Peritoneal malignancies present a unique challenge, as surgical management can be resource intensive, but patients have limited non-surgical treatment options. This review summarizes current data on outcomes and resource utilization to help inform decision-making and case prioritization in times of constrained health care resources. Methods: A rapid literature review was performed, examining surgical and non-surgical outcomes data for peritoneal malignancies. Narrative data synthesis was cross-referenced with relevant societal guidelines. Peritoneal malignancy surgeons and medical oncologists reviewed recommendations to establish a national perspective on case triage and mitigating treatment strategies. Results and Conclusions: Triage of peritoneal malignancies during this time of restricted health care resource is nuanced and requires multidisciplinary discussion with consideration of individual patient factors. Prioritization should be given to patients where delay may compromise resectability of disease, and where alternative treatment options are lacking. Mitigating strategies such as systemic chemotherapy and/or surgical deferral may be utilized with close surveillance for disease stability or progression, which may affect surgical urgency. Unique hospital capacity, and ability to manage the complex post-operative course for these patients must also be considered to ensure patient and system needs are aligned.

Unravelling the Mysteries of the Mesentery

The mesentery and its folds tether the small bowel loops to the posterior abdominal wall. It transmits nerves, vessels, and lymph ensconced in a fatty sponge layer wrapped in a thin glistening peritoneum, from and to the small bowel. Not only does this flexible dynamic fatty apron house various localized primary benign and malignant lesions, it is often involved in and gives an indication of generalized or systemic diseases in the body. An understanding of the anatomy, components, and function of the mesentery helps to classify mesenteric abnormalities. This further allows for characterizing radiological patterns and appearances specific to certain disease entities. Recent reviews of mesenteric anatomy have kindled new interest in its function and clinical applications, heralding the possibility of revision of its role in diseases of the abdomen.

Modeling of Chemoperfusion vs. Intravenous Administration of Cisplatin in Wistar Rats: Adsorption and Tissue Distribution

Hyperthermic intraperitoneal chemoperfusion (HIPEC) is an established form of locoregional chemotherapy of peritoneum tumors. However, its efficacy and safety status remain a controversy, partially, due to scarce data on pharmacokinetics and toxicity profile of drugs under HIPEC. In the current study, 24 female Wistar rats were randomly assigned to receive cisplatin as HIPEC (n = 12, 20 mg/kg) or intravenously (i.v., n = 9, 4 mg/kg). The subgroups of three animals were used for the initial, intermediate, and late phases of the pharmacokinetic assessment. The animals were sacrificed on days 1 and 5. Blood, liver, kidney, and ovaries were evaluated for platinum content. Histological and immunohistochemical evaluation was undertaken in the liver and kidney. A trend for higher blood plasma platinum levels was observed for HIPEC compared to i.v. Significantly lower (p < 0.001) relative platinum binding to the proteins was observed in HIPEC animals compared to the i.v. administration. A five-fold higher concentration of cisplatin in HIPEC resulted in a ca. 2.5-fold increase in total blood platinum and ca. two-fold increase in blood ultrafitrable platinum (“free” Pt). Immunohistochemistry revealed higher kidney and liver damage after i.v. administration of cisplatin compared to HIPEC, although a five-fold higher dose of cisplatin was applied in HIPEC. Together with relatively lower absorption to the systemic circulation in HIPEC, higher protein binding is probably the primary reason for lower observed toxicity in HIPEC animals.

Development and validation of prognostic nomograms for pseudomyxoma peritonei patients after surgery: A population-based study

BACKGROUND

The aim of study was to develop and validate nomograms for predicting overall survival (OS) and cancer-specific survival (CSS) of patients with pseudomyxoma peritonei (PMP) and compare the predictive accuracy with the American Joint Committee on Cancer (AJCC) staging system.

METHODS

Data of 4959 PMP patients who underwent surgical resection were collected between 2004 and 2015 from the Surveillance Epidemiology and End Results (SEER) database. All included patients were divided into training (n = 3307) and validation (n = 1652) cohorts. The Kaplan-Meier method and Cox proportional hazard model were applied. Nomograms were validated by discrimination and calibration. Finally, concordance index (C-index) was used to compare the predictive performance of nomograms with that of the AJCC staging system.

RESULTS

According to the univariate and multivariate analyses of training sets, both nomograms for predicting OS and CSS combining age, grade, location, N stage, M stage, and chemotherapy were identified. Nomograms predicting OS also incorporated T stage and the number of lymph nodes removed (LNR). The calibration curves showed good consistency between predicted and actual observed survival. Moreover, C-index values demonstrated that the nomograms predicting both OS and CSS were superior to the AJCC staging system in both cohorts.

CONCLUSION

We successfully developed and validated prognostic nomograms for predicting OS and CSS in PMP patients. Two nomograms were more accurate and applicable than the AJCC staging system for predicting patient survival, which may help clinicians stratify patients into different risk groups, tailor individualized treatment, and accurately predict patient survival in PMP.

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) for colorectal and appendiceal peritoneal metastases - The Hong Kong experience and literature review

INTRODUCTION

Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) is increasingly used to treat peritoneal metastases from appendiceal or colorectal origin. We evaluate our institution's experience and survival outcomes with this procedure, and its efficacy in symptom relief.

METHODS

This is a single-centre retrospective observational study on patients with peritoneal metastases (PM) from appendiceal neoplasm or colorectal cancer who underwent CRS/HIPEC in Queen Mary Hospital. Our primary endpoints were overall survival (OS) and morbidity and mortality of this procedure; secondary endpoints included disease-free survival (DFS) and symptom-free survival.

RESULTS

Between 2006 and 2018, thirty CRS/HIPEC procedures were performed for 28 patients - 17 (60.7%) had appendiceal PM while 11 (39.9%) had colorectal PM. The median peritoneal cancer index was 20; complete cytoreduction was achieved in 83.3% patients. High-grade morbidity occurred in 13.3% cases. There was no 30-day mortality. Two-year OS were 71.6% and 50% for low-grade appendiceal PM and colorectal PM patients (p = 0.20). Complete cytoreduction improved OS (2-year OS 75.4% vs 20%, p = 0.04). Median DFS was 11.8 months. Median symptom-free duration was 36.8 months; patients with complete cytoreduction were more likely to remain asymptomatic (82.9% at 1 year, vs 60% in incomplete cytoreduction group, p < 0.01). 91.7% low-grade appendiceal PM patients and 58.4% colorectal PM patients remained asymptomatic at post-operative one year (p = 0.31).

CONCLUSION

CRS/HIPEC is beneficial to appendiceal PM and selected colorectal PM patients - improving survival and offering prolonged symptom relief, with reasonable morbidity and mortality. Complete cytoreduction is key to realising this benefit.

The role of mucin cell-free DNA detection as a new marker for the study of acellular pseudomyxoma peritonei of appendicular origin by liquid biopsy

Background:

Acellular pseudomyxoma peritonei (aPMP) is a rare peritoneal malignancy characterized by the accumulation of large amounts of mucin (lacking tumor cells) in the peritoneum. Many cases account for several kilograms of mucin to be screened by the pathologist. This is a comprehensive study of three patients with aPMP, whose tumors showed KRAS mutation, allowing for the tracking of this marker by liquid biopsy.

Methods:

Pre and post-surgery plasma, and mucin removed during cytoreductive surgery were collected from the patients. KRAS mutations were analyzed using droplet digital polymerase chain reaction (ddPCR). Mucin was injected in mice. KRAS and cytokine levels were measured in plasma of the mice using ddPCR and a magnetic bead-based assay. Mucin microbiome was analyzed by 16S rRNA sequencing.

Results:

KRAS mutations were detected in mucin cell-free DNA (cfDNA) from the three patients but not in the pre or post-surgery plasma. Electron microscopy detected microparticles (diameter <0.4 µm) in mucin. Mucin from one patient grew up inside the peritoneal cavity of mice and human KRAS was identified in mucin cfDNA, but not in plasma. All mucins showed the same bacterial profile. Cytokine levels were slightly altered in mice.

Conclusions:

The three aPMP patients included in this study shared some common aspects: the absence of tumor cells in mucin, the presence of KRAS mutated cfDNA in mucin, and the absence of this tumor-derived mutation in the bloodstream, providing additional information to the routine pathological examinations and suggesting that mucin cfDNA could potentially play a role in aPMP recurrence and prognosis.

Outcomes Following Cytoreduction and HIPEC for Pseudomyxoma Peritonei: 10-Year Experience

BACKGROUND

Pseudomyxoma peritonei (PMP) is a rare clinical presentation, with considerable morbidity and mortality if left untreated. In recent decades, there is growing acceptance for the use of cytoreductive surgery (CRS) with heated intraperitoneal chemotherapy (HIPEC). The aim of this study was to report on our 10-year single-center experience on outcomes following CRS and HIPEC for PMP of appendiceal origin.

METHODS

A retrospective analysis of a prospectively maintained database of all patients undergoing CRS and HIPEC for PMP of appendiceal origin over a 10-year period at a statewide referral center was conducted.

RESULTS

One hundred and seventy-five cytoreductive procedures were undertaken in 140 patients. The mean patient age was 57.4 years, with a female preponderance (56%). The median PCI was 16, with 73.1% of cases having a complete cytoreduction. Grade III/IV complications occurred in 36 (20.6%) cases, with no mortalities. The median overall and disease-free survival was 100 months and 40 months, respectively, with a 71% 5-year survival. High-grade histology was the main factor identified as an independent predictor of worse overall survival.

CONCLUSION

CRS and HIPEC are safe with acceptable rates of morbidity. It can provide very favorable survival in patients with PMP. High-grade histology is a key prognostic factor associated with a worse overall survival.

Appendiceal tumours and pseudomyxoma peritonei: Literature review with PSOGI/EURACAN clinical practice guidelines for diagnosis and treatment

Pseudomyxoma Peritonei (PMP) is a rare peritoneal malignancy, most commonly originating from a perforated epithelial tumour of the appendix. Given its rarity, randomized controlled trials on treatment strategies are lacking, nor likely to be performed in the foreseeable future. However, many questions regarding the management of appendiceal tumours, especially when accompanied by PMP, remain unanswered. This consensus statement was initiated by members of the Peritoneal Surface Oncology Group International (PSOGI) Executive Committee as part of a global advisory role in the management of uncommon peritoneal malignancies. The manuscript concerns an overview and analysis of the literature on mucinous appendiceal tumours with, or without, PMP. Recommendations are provided based on three Delphi voting rounds with GRADE-based questions amongst a panel of 80 worldwide PMP experts.

Imaging findings for mucinous tumors of the abdomen and pelvis

This article aims to describe the imaging findings for mucinous tumors of the abdomen and pelvis, which have a similar appearance on imaging tests regardless of the organ in which they develop. Due to the high water content of mucus, the appearance of these tumors is generally similar to that of water on ultrasonography, computed tomography, and magnetic resonance imaging. Another common feature of mucin-producing tumors is that calcifications are often present. The rupture of these lesions and accumulation of mucinous material in the peritoneal cavity gives rise to pseudomyxoma peritonei. It is important to identify mucinous tumors because they have a different prognosis and clinical course than non-mucinous tumors and require different management. Depending on their anatomic location and their imaging characteristics, the treatment approach varies from follow-up to radical surgery together with chemotherapy or radiotherapy or both.