Genomic characterization and detection of potential therapeutic targets for peritoneal mesothelioma in current practice.

Peritoneal mesothelioma (PeM) is an aggressive tumor with limited treatment options. The current study aimed to evaluate the value of next generation sequencing (NGS) of PeM samples in current practice. Foundation Medicine F1CDx NGS was performed on 20 tumor samples. This platform assesses 360 commonly somatically mutated genes in solid tumors and provides a genomic signature. Based on the detected mutations, potentially effective targeted therapies were identified. NGS was successful in 19 cases. Tumor mutational burden (TMB) was low in 10 cases, and 11 cases were microsatellite stable. In the other cases, TMB and microsatellite status could not be determined. BRCA1 associated protein 1 (BAP1) mutations were found in 32% of cases, cyclin dependent kinase inhibitor 2A/B (CDKN2A/B) and neurofibromin 2 (NF2) mutations in 16%, and ataxia-telangiectasia mutated serine/threonine kinase (ATM) in 11%. Based on mutations in the latter two genes, potential targeted therapies are available for approximately a quarter of cases (i.e., protein kinase inhibitors for three NF2 mutated tumors, and polyADP-ribose polymerase inhibitors for two ATM mutated tumors). Extensive NGS analysis of PeM samples resulted in the identification of potentially effective targeted therapies for about one in four patients. Although these therapies are currently not available for patients with PeM, ongoing developments might result in new treatment options in the future.

Development of a prediction model for recurrence in patients with colorectal peritoneal metastases undergoing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy.

INTRODUCTION: Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) improves survival outcomes for selected patients with colorectal peritoneal metastases (PM), but recurrence rates are high. The aim of this study was to develop a tool to predict recurrence in patients with colorectal PM that undergo CRS-HIPEC. MATERIALS AND METHODS: For this retrospective cohort study, data of patients that underwent CRS-HIPEC for colorectal PM from four Dutch HIPEC centers were used. Exclusion criteria were perioperative systemic therapy and peritoneal cancer index (PCI) ≥20. Nine previously identified factors were considered as predictors: gender, age, primary tumor characteristics (location, nodal stage, differentiation, and mutation status), synchronous liver metastases, preoperative Carcino-Embryonal Antigen (CEA), and peritoneal cancer index (PCI). The prediction model was developed using multivariable Cox regression and validated internally using bootstrapping. The performance of the model was evaluated by discrimination and calibration. RESULTS: In total, 408 patients were included. During the follow-up, recurrence of disease occurred in 318 patients (78%). Significant predictors of recurrence were PCI (HR 1.075, 95% CI 1.044-1.108) and primary tumor location (left sided HR 0.719, 95% CI 0.550-0.939). The prediction model for recurrence showed fair discrimination with a C-index of 0.64 (95% CI 0.62, 0.66) after internal validation. The model was well-calibrated with good agreement between the predicted and observed probabilities. CONCLUSION: We developed a prediction tool that could aid in the prediction of recurrence in patients with colorectal PM who undergo CRS-HIPEC.

Adjuvant dendritic cell-based immunotherapy after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in patients with malignant peritoneal mesothelioma: a phase II clinical trial.

BACKGROUND: Malignant peritoneal mesothelioma (MPM) is an aggressive malignancy with a poor prognosis. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) improves survival outcomes, but recurrence rates remain high. Dendritic cell-based immunotherapy (DCBI) showed promising results in patients with pleural mesothelioma. The primary aim of this trial was to determine feasibility of adjuvant DCBI after CRS-HIPEC. METHODS: This open-label, single-center, phase II clinical trial, performed in the Erasmus MC Cancer Institute Rotterdam, the Netherlands, included patients with epithelioid MPM. 4-6 weeks before CRS-HIPEC leukapheresis was performed. 8-10 weeks after surgery, DCBI was administered three times biweekly. Feasibility was defined as administration of at least three adjuvant vaccinations in 75% of patients. Comprehensive immune cell profiling was performed on peripheral blood samples prior to and during treatment. RESULTS: All patients who received CRS-HIPEC (n=16) were successfully treated with adjuvant DCBI. No severe toxicity related to DCBI was observed. Median progression-free survival (PFS) was 12 months (IQR 5-23) and median overall survival was not reached. DCBI was associated with increased proliferation of circulating natural killer cells and CD4+ T-helper (Th) cells. Co-stimulatory molecules, including ICOS, HLA-DR, and CD28 were upregulated predominantly on memory or proliferating Th-cells and minimally on CD8+ cytotoxic T-lymphocytes (CTLs) after treatment. However, an increase in CD8+ terminally differentiated effector memory (Temra) cells positively correlated with PFS, whereas co-expression of ICOS and Ki67 on CTLs trended towards a positive correlation. CONCLUSIONS: Adjuvant DCBI after CRS-HIPEC in patients with MPM was feasible and safe, and showed promising survival outcomes. DCBI had an immune modulatory effect on lymphoid cells and induced memory T-cell activation. Moreover, an increase of CD8+ Temra cells was more pronounced in patients with longer PFS. These data provide rationale for future combination treatment strategies. TRIAL REGISTRATION NUMBER: NTR7060; Dutch Trial Register (NTR).

Phase I study of intraperitoneal irinotecan combined with palliative systemic chemotherapy in patients with colorectal peritoneal metastases.

BACKGROUND: Patients with colorectal peritoneal metastases who are not eligible for cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) owing to extensive peritoneal disease have a poor prognosis. It was hypothesized that these patients may benefit from the addition of intraperitoneal irinotecan to standard palliative systemic chemotherapy. METHODS: This was a classical 3 + 3 phase I dose-escalation trial in patients with colorectal peritoneal metastases who were not eligible for CRS-HIPEC. Intraperitoneal irinotecan was administered every 2 weeks, concomitantly with systemic FOLFOX (5-fluorouracil, folinic acid, oxaliplatin)-bevacizumab. The primary objective was to determine the maximum tolerated dose and dose-limiting toxicities. Secondary objectives were to elucidate the systemic and intraperitoneal pharmacokinetics, safety profile, and efficacy. RESULTS: Eighteen patients were treated. No dose-limiting toxicities were observed with 50 mg (4 patients) and 75 mg (9 patients) intraperitoneal irinotecan. Two dose-limiting toxicities occurred with 100 mg irinotecan among five patients. The maximum tolerated dose of intraperitoneal irinotecan was established to be 75 mg, and it was well tolerated. Intraperitoneal exposure to SN-38 (active metabolite of irinotecan) was high compared with systemic exposure (median intraperitoneal area under the curve (AUC) to systemic AUC ratio 4.6). Thirteen patients had a partial radiological response and five had stable disease. Four patients showed a complete response during post-treatment diagnostic laparoscopy. Five patients underwent salvage resection or CRS-HIPEC. Median overall survival was 23.9 months. CONCLUSION: Administration of 75 mg intraperitoneal irinotecan concomitantly with systemic FOLFOX-bevacizumab was safe and well tolerated. Intraperitoneal SN-38 exposure was high and prolonged. As oncological outcomes were promising, intraperitoneal administration of irinotecan may be a good alternative to other, more invasive and costly treatment options. A phase II study is currently accruing.

Patients with extensive colorectal peritoneal metastases who are not eligible for surgery and heated intraperitoneal chemotherapy have poor survival. The authors tried to improve the survival of these patients by adding intraperitoneal (inside the abdominal cavity) chemotherapy to standard palliative chemotherapy which is administered into the bloodstream. In this trial, irinotecan (a type of chemotherapy) was administered into the abdomen of patients with extensive colorectal peritoneal metastases. The authors investigated which dose could be administered safely in combination with standard palliative chemotherapy. They also looked into toxicity, safety, benefit, and movement of the drug in the body. Eighteen patients were treated in this study. The maximum tolerated dose of intraperitoneal irinotecan was 75 mg. It was well tolerated and could be administered safely. The intra-abdominal amount of irinotecan was high, whereas the amount of irinotecan in the blood remained low. The benefits of intra-abdominal irinotecan were promising. Because of this, a new study has been started to further investigate this new combination chemotherapy for colorectal cancer.

Treatment and Survival Outcomes for Patients with Colorectal Peritoneal Metastases Deemed Ineligible for Cytoreductive Surgery (CRS) with Hyperthermic Intraperitoneal Chemotherapy (HIPEC): Results of a Retrospective Study.

BACKGROUND: Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) is a treatment option for selected patients with colorectal peritoneal metastases (PM). This report provides an overview of treatment and survival outcomes for patients deemed ineligible for CRS-HIPEC. METHODS: Colorectal PM patients referred to a tertiary center from 2014 to 2020 that were ineligible for CRS-HIPEC were included. Patient, tumor, and treatment characteristics were provided. Survival analyses were performed using the Kaplan-Meier method. RESULTS: Of 476 patients referred for CRS-HIPEC, 227 (48%) were deemed ineligible. Median follow-up was 15 months [IQR 10-22]. Data on follow-up treatment was available for 198 patients, of which 73% received systemic therapy. These patients had a median overall survival (OS) of 17 months [IQR 9-25]. For patients receiving best supportive care (BSC) median OS was 4 months [IQR 2-9]. The main reason for ineligibility was extensive PM (42%), with a median OS of 11 months [IQR 5-18]. Patients deemed ineligible due to (extensive) liver (9%) or lung metastases (8%) showed longer OS (median 22 months, IQR 8-27, and 24 months, IQR 12-29, respectively) than patients with extensive PM (median 11 months, IQR 5-18) or distant lymph node metastases (median 14 months, IQR 4-25). CONCLUSION: The main reason for CRS-HIPEC ineligibility was extensive PM. The majority of patients received systemic therapy. Patients deemed ineligible due to extra-peritoneal metastases had better survival outcomes than patients deemed ineligible due to extensive PM.

The Impact of Low Skeletal Muscle Mass on Short- and Long-Term Outcomes After Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy.

BACKGROUND: Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) is a potentially curative treatment for peritoneal metastases from colorectal cancer (CRC) or pseudomyxoma peritonei (PMP). Because of the considerable morbidity of this treatment, optimal patient selection is key. This study aimed to assess the impact of low skeletal muscle mass (SMM) on outcomes after CRS-HIPEC. METHODS: Patients who underwent CRS-HIPEC between 2014 and 2020 at a tertiary center were included. SMM was measured on computed tomography by means of the L3 muscle index. Postoperative complications and survival outcomes were compared between groups by use of logistic regression and Kaplan-Meier survival analyses. RESULTS: Of 284 included patients, 149 had low SMM. Occurrence of severe postoperative complications did not differ between groups (28.9% for patients with low vs. 34.1% for patients with normal SMM). Low SMM was not associated with postoperative complications (p = 0.344). For CRC patients, no significant differences were observed in disease-free (DFS) or overall survival (OS) between patients with low (median DFS 7 months [IQR 4-14], median OS 33 months [IQR 14-NR]) and patients with normal SMM (median DFS 8 months [IQR 5-20], median OS 35 months [IQR 18-NR]). Regarding PMP, survival outcomes did not significantly differ between groups (3-year DFS 47.3% for patients with low SMM vs. 54.5% for patients with normal SMM, p = 0.676; 3-year OS 70.8% vs. 90.9% respectively, p = 0.172). CONCLUSIONS: Low SMM could not be identified as a predictor of severe complications or survival outcomes after CRS-HIPEC.

Intraperitoneal paclitaxel for patients with primary malignant peritoneal mesothelioma: a phase I/II dose escalation and safety study-INTERACT MESO.

INTRODUCTION: Malignant peritoneal mesothelioma (MPM) is a rare, aggressive tumour arising primarily from the peritoneum. The only potentially curative treatment is cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC). However, the majority of patients are not eligible to undergo this treatment. The benefit of systemic treatment for these patients is limited at the cost of considerable morbidity. Hence, there is a need for appropriate palliative treatment options for patients with MPM. As MPM rarely disseminates outside the abdominal cavity, these patients might benefit from local treatment. A higher, more effective dose of chemotherapy can directly be delivered at the site of the disease. Systemic uptake will be limited, likely resulting in less toxicity. The aim of the INTERACT MESO trial is to determine the maximum tolerable dose of intraperitoneal paclitaxel monotherapy in patients with MPM. Secondary endpoints are to assess safety and toxicity, feasibility and the pharmacokinetic profile of this treatment. METHODS AND ANALYSIS: The INTERACT MESO trial is a prospective, open-label, single-centre, phase I study with a classic three-plus-three dose escalation design. The study population consists of adult patients with primary MPM, without extra-abdominal disease, who are not eligible to undergo CRS-HIPEC. According to standard of care work-up for CRS-HIPEC, patients will undergo diagnostic laparoscopy to determine the feasibility of CRS-HIPEC. In case CRS-HIPEC is not considered feasible, a peritoneal port-a-cath (PAC) system will be placed. Through this PAC, 8-16 weekly cycles of intraperitoneal chemotherapy will be administered. ETHICS AND DISSEMINATION: The Central Committee on Research Involving Human Subjects (CCMO, The Hague, The Netherlands) and the Medical Research Ethics Committee (METC, Rotterdam, The Netherlands) have granted permission to carry out this study protocol. The results of this trial will be submitted for publication in a peer-reviewed scientific journal. TRIAL REGISTRATION NUMBER: NL9718. EudraCT: 2021-003637-11.

Survival Outcomes After Cytoreductive Surgery with Hyperthermic Intraperitoneal Chemotherapy in Patients with Synchronous Versus Metachronous Onset of Peritoneal Metastases of Colorectal Carcinoma.

BACKGROUND: Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) is a treatment option for peritoneal metastases (PM) from colorectal carcinoma (CRC). Because of considerable morbidity, optimal patient selection is essential. This study was designed to determine the impact of the onset of PM (synchronous vs. metachronous) on survival outcomes after CRS-HIPEC. METHODS: Patients undergoing CRS-HIPEC for colorectal PM in two academic centers in the Netherlands between 2010 and 2020 were eligible for inclusion. Patients were classified as synchronous (s-PM, i.e., diagnosis at time of presentation, staging, or primary surgery) or metachronous onset (m-PM, i.e., diagnosis during follow-up) of colorectal PM. Survival outcomes were compared between groups by Kaplan-Meier survival and Cox regression analyses. RESULTS: Of 390 included patients, 179 (45.9%) had synchronous onset of colorectal PM. These patients more often presented with higher TN-stage and poor differentiation/signet cell histology. Treatment with perioperative chemotherapy was more common in s-PM patients. m-PM patients experienced more serious postoperative complications (Clavien-Dindo ≥ III). There was no significant difference in disease-free survival (DFS) between s-PM (median 9 months, interquartile range [IQR] 5-15) and m-PM patients (median 8 months, IQR 5-17). Overall survival (OS) was significantly shorter for s-PM (median 28 months, IQR 11-48) versus m-PM patients (median 33 months, IQR 18-66, p = 0.049). Synchronous onset of PM was not independently associated with OS in a multivariable analysis. CONCLUSIONS: Synchronous onset of colorectal PM was associated with poor tumor characteristics and more advanced disease, but was not an independent predictor of survival outcomes after CRS-HIPEC.