Well differentiated papillary peritoneal mesothelioma treated by cytoreduction and hyperthermic intraperitoneal chemotherapy-the experience of the PSOGI registry

Long-Term Survival in Patients Treated with Cytoreduction and Heated Intraperitoneal Chemotherapy for Peritoneal Mesothelioma at a Single High-Volume Center

BACKGROUND

Malignant peritoneal mesothelioma (MPM) is a rare diagnosis with a dismal prognosis if untreated. Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) is shown to significantly improve survival. Our institution is uniquely positioned to report long-term outcomes in MPM with CRS-HIPEC, due to our robust peritoneal surface disease program existing over the past three decades.

METHODS

Our prospectively maintained, single-institution database of CRS-HIPEC cases was reviewed, identifying 111 consecutive patients with MPM over 28 years (1993-2021). Prognostic, operative, and pathologic factors were reviewed. Overall survival (OS) and conditional survival (CS) analyses were performed.

RESULTS

The average age was 55.1 years; 58.6% of patients were male; 17 of 111 patients (15.3%) had a second CRS-HIPEC. At first CRS-HIPEC, the average PCI score was 18.7, and the perfusate drugs were platinum-based (72.1%) and mitomycin C (27.9%). The resection status at first CRS-HIPEC was R2a (46.4%), followed by R0-1 (29.1%), and R2b-c (24.5%). Median OS was 3.3 years for the entire cohort, with 75th and 25th percentiles at 10.7 months and 10.6 years. Median CS was improved if patients survived to the 1-year postoperative mark (4.9 years, p < 0.01) and trended toward further improvement with each passing year. If 3-year postoperative survival was achieved, the median CS improved to 6.1 years.

CONCLUSIONS

This represents one of the largest and lengthiest, single-center, longitudinal, case series of peritoneal mesothelioma treated with CRS-HIPEC. The OS suggests efficacy for CRS-HIPEC for MPM. Long-term survival improves significantly after patients achieve the 1-year, postoperative mark.

Diagnostic and Therapeutic Pathway in Diffuse Malignant Peritoneal Mesothelioma

Diffuse malignant peritoneal mesothelioma (DMPM) is a rare form of mesothelioma that carries a very poor prognosis. The 5-year overall survival is about 20% (±5.9). Survival is optimal for patients suitable for cytoreductive surgery (CRS) with Hyperthermic Intraperitoneal Chemotherapy (HIPEC), with a median OS ranging from 34 to 92 months. However, selecting patients for surgery remains a complex task and requires a careful preoperative workup, rational analysis of prognostic profiles, and risk prediction models. Systemic chemotherapy could be offered: (1) in the adjuvant setting for high-risk patients; (2) for patients not eligible for CRS; and (3) for those with recurrent disease. It mainly includes the combination of Platin compound with Pemetrexed or immunotherapy. The biology of DMPM is still largely unknown. However, progress has been made on some fronts, such as telomere maintenance mechanisms, deregulation of apoptosis, tyrosine kinase pathways, and mutation of BRCA1-associated protein 1 (BAP1). Future perspectives should include translational research to improve our understanding of the disease biology to identify druggable targets. We should also clear the role of immune checkpoint inhibitors and investigate new locoregional technologies, such as pressurized intraperitoneal aerosol chemotherapy (PIPAC) or normothermic intraperitoneal chemotherapy (NIPEC).

[Well differentiated papillary mesothelioma: description of three case reports and review of the literature]

Well Differentiated Papillary Mesothelioma (MPBD) is a very rare neoplasm that mainly affects women of reproductive age. The most common location is the peritoneum and it is an incidental finding, with a generally favorable prognosis. We present three cases diagnosed incidentally, in the course of a surgical intervention of various causes, which presented as peritoneal exophytic lesions not detected in the pre-surgical imaging study. It is important to keep this entity in mind, to differentiate it from other neoplasms with an unfavorable prognosis and evolution, such as Malignant Mesothelioma or primary and metastatic carcinomas. Recent studies give the MPBD a specific immunohistochemical and molecular profile that allow a greater diagnostic precision of the entity.

Spontaneous urinary bladder perforation: An unusual presentation of well-differentiated papillary peritoneum mesothelioma

INTRODUCTION

Well-differentiated papillary mesothelioma (WDPM) is a very rare neoplasm. Most of WDPM are asymptomatic and are often incidentally detected during surgery. This report describes a case of WDPM of the peritoneum unexpectedly diagnosed in a male with a spontaneous intraperitoneal bladder rupture.

CASE PRESENTATION

A 65-year-old male presented to our Emergency Department in November 2019 with a two-day history of anuria, abdominal pain, distention, and sepsis. The CT scan reported a large amount of extra and intraperitoneal free fluid. The CT cystogram showed bladder perforations on the dome and on the left lateral wall which was repaired through exploratory laparotomy. Intraoperatively, we encountered extensive suppurative peritonitis with large fibrino-purulent exudation. The purulent perivesical peritoneum was dissected and sent for histopathological examination which unexpectedly resulted in WDPM of the peritoneum.

CONCLUSION

Although we can't affirm with certainty, this case would seem to suggest that WDPM had played a role in patient's clinical presentation. However, further research is necessary to draw stronger conclusion.

Well-Differentiated Papillary Mesothelioma of the Peritoneum Is Genetically Distinct from Malignant Mesothelioma

Well-differentiated papillary mesothelioma (WDPM) is an uncommon mesothelial proliferation that is most commonly encountered as an incidental finding in the peritoneal cavity. There is controversy in the literature about whether WDPM is a neoplasm or a reactive process and, if neoplastic, whether it is a variant or precursor of epithelial malignant mesothelioma or is a different entity. Using whole exome sequencing of five WDPMs of the peritoneum, we have identified distinct mutations in EHD1, ATM, FBXO10, SH2D2A, CDH5, MAGED1, and TP73 shared by WDPM cases but not reported in malignant mesotheliomas. Furthermore, we show that WDPM is strongly enriched with C > A transversion substitution mutations, a pattern that is also not found in malignant mesotheliomas. The WDPMs lacked the alterations involving BAP1, SETD2, NF2, CDKN2A/B, LASTS1/2, PBRM1, and SMARCC1 that are frequently found in malignant mesotheliomas. We conclude that WDPMs are neoplasms that are genetically distinct from malignant mesotheliomas and, based on observed mutations, do not appear to be precursors of malignant mesotheliomas.

Localized malignant mesothelioma, an unusual and poorly characterized neoplasm of serosal origin: best current evidence from the literature and the International Mesothelioma Panel

Localized malignant mesotheliomas (LMM) is an uncommon and poorly recognized neoplasm. Its pathologic diagnosis is often surprising in patients with serosal/subserosal based localized tumors that are clinically suspicious for metastatic lesions or primary sarcomas. Once a tumor is diagnosed as "mesothelioma", LMM is often mistaken for diffuse malignant mesothelioma (DMM). Best currently available evidence about LMM was collected from the literature and cases diagnosed by members of the International Mesothelioma Panel (IMP). One hundred and one (101) LMM have been reported in the English literature. Patients had localized tumors with identical histopathologic features to DMM. Patients ranged in age from 6 to 82 years; 75% were men. Most (82%) of the tumors were intrathoracic. Others presented as intrahepatic, mesenteric, gastric, pancreatic, umbilical, splenic, and abdominal wall lesions. Tumors varied in size from 0.6 to 15 cm. Most patients underwent surgical resection and/or chemotherapy or radiation therapy. Median survival in a subset of patients was 29 months. Seventy two additional LMM from IMP institutions ranged in age from 28 to 95 years; 58.3% were men. Sixty tumors (83.3%) were intrathoracic, others presented in intraabdominal sites. Tumors varied in size from 1.2 to 19 cm. Median survival for 51 cases was 134 months. Best evidence was used to formulate guidelines for the diagnosis of LMM. It is important to distinguish LMM from DMM as their treatment and prognosis is different. A multidisciplinary approach is needed for the diagnosis of LMM as it shows identical histopathology and immunophenotype to DMM.

Peritoneal mesothelioma in Sweden: A population-based study

The study aim was to report survival and morbidity of all patients in Sweden with peritoneal mesothelioma treated with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) as well as investigate whether the survival has increased on a population level since this treatment was nationalized 2011. Study data were collected from the Swedish HIPEC registry and the Swedish National Cancer Registry. All patients with peritoneal mesothelioma scheduled for CRS/HIPEC treatment in Sweden January 2011 to March 2018 were retrieved from the Swedish HIPEC registry. Clinicopathological and survival data were collected. For population‐level analysis, all patients with diffuse malignant peritoneal mesothelioma (DMPM) were identified from the Swedish National Cancer Registry and data were retrieved from two separate 5‐year time periods: 1999‐2003 and 2011‐2015. Thirty‐two patients were accepted for CRS/HIPEC. Four were open/close cases. Two‐year survival rate was 84% or 59% when excluding borderline peritoneal mesotheliomas (n = 17). Median overall survival was not reached. Grade III‐IV Clavien‐Dindo events occurred in 22% with no mortality. From the national cancer registry, 102 DMPM cases were retrieved: 40 cases between 1999 and 2003, and 62 cases between 2011 and 2015 (corresponding to an increase from 0.9 to 1.24/million/year, P = .04). Six patients (10%) received CRS/HIPEC in the second period. Median OS increased between periods from 7 to 15 months and 5‐year survival from 14% to 29% (P = .03). Peritoneal mesothelioma of both borderline and DMPM subtypes undergoing CRS/HIPEC have good long‐term survival. The incidence of DMPM in Sweden has increased. Overall survival has increased alongside the introduction of CRS/HIPEC, which may be a contributing factor.

Well-Differentiated Papillary Mesothelioma of the Peritoneum: A Retrospective Study from the RENAPE Observational Registry

BACKGROUND

Well-differentiated papillary mesothelioma of the peritoneum (WDPMP) is a rare entity. Questions regarding management are still being debated as no more than 50 cases have been reported in the literature.

OBJECTIVE

We aimed to analyze the clinical, therapeutic, and prognostic data of patients with WDPMP from the RENAPE observational registry.

PATIENTS AND METHODS

All patients diagnosed with WDPMP and prospectively included in the RENAPE national registry between 2010 and 2018 were also included in our study. Expert pathologists from the RENA-PATH group confirmed all cases. All clinical, therapeutic, postoperative, and prognostic data were extracted and analyzed.

RESULTS

We report on 56 patients with a mean age of 52 years (range 21-74). WDPMP was incidentally diagnosed during imaging or surgery in 16% and 36% of patients, respectively, and an association with synchronous malignancy was found in 18% of patients. Nine lesions showed discrete signs of fatty invasion. The median Peritoneal Cancer Index was 11 (range 0-33). Eleven patients were treated with definitive excision, 4 were treated with cytoreductive surgery (CRS) only, 37 were treated with CRS and hyperthermic intraperitoneal chemotherapy (HIPEC), and 2 were treated with CRS plus HIPEC plus early postoperative intraperitoneal chemotherapy. CRS was considered to be complete in 90% of cases. One patient died postoperatively and 16 patients (31%) faced postoperative complications. The median disease-free survival was 144 months; Four patients relapsed, with a median period of 27 months. No prognostic factors could be identified.

CONCLUSIONS

Our analysis confirms the favorable prognosis of WDPMP. CRS and HIPEC could be a therapeutic option for diffuse, symptomatic, and/or recurrent disease.