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Immunotherapy with immune checkpoint inhibitors has significantly improved the survival of patients with MSI/dMMR mCRC. These tumors are associated with a specific metastatic spread, i.e. frequent peritoneal carcinomatosis (PC) that may be treated surgically when there is no other metastatic location. We aimed at evaluating the prognosis of patients treated with immune checkpoint inhibitors for MSI/dMMR mCRC with isolated PC.All consecutive patients with isolated PC from MSI/dMMR mCRC, initially considered as unresectable by multidisciplinary team meeting, treated with immune checkpoint inhibitors were included in this French multicenter cohort study.Among 45 patients included, we observed 11 complete responses and 10 partial responses for an overall response rate iRECIST of 46%. After a median follow-up of 24.4 months, the median progression-free survival (PFS) and overall survival (OS) were not reached. Seven of the eight patients who underwent cytoreductive surgery after treatment with anti-PD1 ± anti-CTLA-4 were in complete pathologic response.These results demonstrate long-term benefit of immune checkpoint inhibitors for patients with isolated PC from MSI/dMMR mCRC. Such treatment appears as the best therapeutic option for patients with isolated PC from MSI/dMMR mCRC. With a majority of pathological complete responses for patients who underwent surgery for residual lesions, the value of such therapeutic strategy remains unknown.

Objectives Pseudomyxoma peritonei (PMP) is a rare cancer currently affecting over 11,736 patients across Europe. Since PMP is so uncommon, collaboration between scientific centers is key to discovering the mechanisms behind the disease, efficient treatments, and targets pointing to a cure. To date, no consensus has been reached on the minimum data that should be collected during PMP research studies. This issue has become more important as biobanking becomes the norm. This paper begins the discussion around a minimum data set that should be collected by researchers through a review of available clinical trial reports in order to facilitate collaborative efforts within the PMP research community. Content A review of articles from PubMed, CenterWatch, ClinicalTrials.gov and MedRxiv was undertaken, and clinical trials reporting PMP results selected. Summary There is a core set of data that researchers report, including age and sex, overall survival, peritoneal cancer index (PCI) score, and completeness of cytoreduction, but after this, reports become variable. Outlook Since PMP is a rare disease, it is important that reports include as large of a number of standardised data points as possible. Our research indicates that there is still much ground to cover before this becomes a reality.

The differentiation between reactive mesothelial hyperplasia (RMH) and diffuse malignant peritoneal mesothelioma (DMPM) is challenging especially when applied on peritoneal small samples. The use of BRCA-associated protein 1 (BAP1) and methylthioadenosine phosphorylase (MTAP) immunostains is familiar to identify malignant mesothelial proliferation. Recently, nuclear 5-hydroxymethylcytosine (5-hmC) was reported to be a new recognition tool of pleural mesothelial malignancy on surgical specimens. However, application of 5-hmC immunostaining has not yet studied in peritoneal specimens from small biopsies or cytology cell-blocks. The aim was to assess the diagnostic accuracy of this new marker combination to distinguish DMPM from RMH in biopsies and cell-blocks. Seventy-five cases were analyzed; among which, 38 were of cytological specimens including 6 RMH and 32 DMPM, and 37 tissue biopsies with 7 RMH and 30 DMPM. BAP1, MTAP, and 5-hmC immunostains were performed on all cases. RMH cases exhibited a retained staining with all immunostains. Among DMPM, BAP1 was lost in 71.8% of cytology cell-blocks and 66.7% of biopsies. MTAP was lost in 40.6% of cytology cell-blocks and 33.3% of biopsies. 5-hmC was lost in 40.6% of cytology cell-blocks and 30% of biopsies. The combination of BAP1, MTAP, and 5-hmC showed the best accuracy in differential diagnosis between RMH and DMPM (sensitivity = 0.84, specificity = 1 in cytology cell-blocks; sensitivity = 0.90, specificity = 1 in biopsy). The best diagnostic combination in peritoneal cytology effusion fluids and biopsies samples provided by BAP1, MTAP, and 5-hmC should be applied on a diagnostic step-wise algorithm by pathologists involved into the management of DMPM, because of their therapeutic implications.

Introduction This document is a summary of the French Intergroup guidelines regarding the management of appendicular epithelial tumors (AT) and pseudomyxoma peritonei (PMP) published in March 2020, available on the website of the French Society of Gastroenterology (SNFGE) ( www.tncd.org ). Methods All French medical societies specialized in the management of AT and PMP collaboratively established these recommendations based on literature until December 2019 and the results of a Delphi vote carried out by the Peritoneal Surface Oncology Group International experts, and graded into 4 categories (A, B, C, Expert Agreement) according to their level of evidence. Results AT and PMP are rare but represent a wide range of clinico-pathological entities with several pathological classification systems and different biological behaviors. Their treatment modalities may vary accordingly and range from simple surveillance or laparoscopic appendectomy to complete cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) and / or systemic chemotherapy. The prognosis of these neoplasms may also largely vary according to their pathological grade and spreading at diagnosis or during the follow-up. Given the rarity of certain situations, the therapeutic strategy adapted to each patient, must be discussed in a specialized multidisciplinary meeting after a specialized pathological and radiological pre-therapeutic assessment and a clinical examination by a surgeon specializing in the management of rare peritoneal malignancies. Conclusion These recommendations are proposed to achieve the most beneficial strategy in a daily practice as the wide range and the rareness of these entities renders their management challenging. These guidelines are permanently being reviewed.

Objectives Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a promising treatment for peritoneal cancer that entails, however, potential risks for the caregivers in the operating room (OR). This study aimed to reach a consensus within the PIPAC community on a comprehensive safety protocol. Methods Active PIPAC centers were invited to participate in a two-round Delphi process on 43 predefined items: concise summaries of the existing evidence were presented together with questions formulated using the population, intervention, comparator, and outcome framework. According to the Grading of Recommendations Assessment, Development, and Evaluation, the strength of recommendation was voted by panelists, accepting a consensus threshold of ≥50% of the agreement for any of the four grading options, or ≥70% in either direction. Results Forty-seven out of 66 invited panelists answered both rounds (response rate 76%). The consensus was reached for 41 out of 43 items (95.3%). Strong and weak recommendations were issued for 30 and 10 items, respectively. A positive consensual recommendation was issued to activate laminar airflow without specific strength, neither strong nor weak. No consensus was reached for systematic glove change for caregivers with a high risk of exposure and filtering facepiece mask class 3 for caregivers with low risk of exposure. Conclusions A high degree of consensus was reached for a comprehensive safety protocol for PIPAC, adapted to the risk of exposure for the different caregivers in the OR. This consensus can serve as a basis for education and help reach a high degree of adherence in daily practice.

Diffuse malignant peritoneal mesothelioma (DMPM) is an aggressive primary peritoneal neoplasia. At diagnosis, few patients are eligible for a recommended cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Among neoadjuvant strategies, pressurized intraperitoneal aerosol chemotherapy (PIPAC) combined with systemic chemotherapy has been recently proposed. This study evaluated this strategy in a cohort of DMPM patients. Patients with DMPM and primary or recurrent non-resectable diseases who received at least one PIPAC procedure in alternation with systemic chemotherapy were included in this retrospective study to analyze oncologic outcomes. Overall, 26 DMPM patients were treated with at least one PIPAC, including 20 patients with no previous CRS. Of 22 patients (85%) who had symptoms, 9 had perceptible ascites. Overall, 79 PIPAC procedures were performed, with half of the patients receiving three PIPAC procedures or more. Among eight patients (31%), 10 adverse events (13% of procedures) were reported, including two severe complications, both corresponding to digestive perforations. Improvement of symptoms was reported for 32% of the patients, whereas control of ascites was noted in 46%. All but one procedure among 14 patients (54%) secondarily treated by CRS-HIPEC were considered complete resections. After a median follow-up period of 29.6 months (95% confidence interval [CI], 17.6–not reached [NR]), the median overall survival period was 12 months (95% CI 11.1–NR). The median progression-free survival (PFS) was significantly better among the patients who underwent resection than among those who did not (33.5 vs 7.4 months; hazard ratio [HR], 0.18; 95% CI 0.06–0.755; p < 0.001). For patients with initially non-resectable DMPM, PIPAC is feasible for treatment with neoadjuvant intent and could facilitate complete secondary resection.

Introduction Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a new surgical technique for the treatment of initially unresectable peritoneal carcinomatosis (PC). Our objective was to compare the results of PIPAC associated with systemic chemotherapy (PIPAC_CHEM) with those of systemic chemotherapy alone (ONLY_CHEM) in patients with gastric PC without metastasis other than peritoneal, and the WHO performance status Methods This was a retrospective, single center, comparative non-randomized study. Seventeen PIPAC_CHEM patients were compared to 29 ONLY_CHEM patients. The primary endpoint was overall survival at 6 months from diagnosis of PC. Results Ninety-eight patients were screened and 46 were included (PIPAC_CHEM, n = 17; ONLY_CHEM, n = 29). The PIPAC_ CHEM population was significantly younger (median 64 years [56; 68] vs 74 years [61; 79]; p = 0.0054). Median PIPAC session per patient is 2 [1-3]. Six-month survival was significantly higher in the PIPAC_CHEM group than in the ONLY_CHEM group 16/17 (94.1% [65-99.2]) vs 19/29 (65.5% [45.4-79.7]), respectively; p = 0.029. Over the entire follow-up, median survival [95% CI] was 12.8 months [7.2-34.3] with PIPAC vs 9.1 months [5.4-11.5] without, p = 0.056. At 6 months, median length of additional hospitalization was significantly less for PIPAC_CHEM (median 2 days [2-7]) than without PIPAC (median 11 days [3-21]) (p = 0.045). Conclusion The overall survival at 6 months after the diagnosis of carcinomatosis was significantly better for PIPAC_CHEM patients. This difference appears to continue until at least 18 months. At 6 months, days of additional hospitalization was significantly less in the PIPAC_CHEM group. Trial registration Clinicaltrials.gov Identifier: NCT 04,879,953.

Background The incidence of gastric poorly cohesive carcinoma (PCC) is increasing. The prognosis for patients with peritoneal metastases remains poor and the role of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) is controversial. The aim was to clarify the impact of gastric PCC with peritoneal metastases treated by CRS with or without HIPEC. Methods All patients with peritoneal metastases from gastric cancer treated with CRS with or without HIPEC, in 19 French centres, between 1989 and 2014, were identified from institutional databases. Clinicopathological characteristics and outcomes were compared between PCC and non-PCC subtypes, and the possible benefit of HIPEC was assessed. Results In total, 277 patients were included (188 PCC, 89 non-PCC). HIPEC was performed in 180 of 277 patients (65 per cent), including 124 of 188 with PCC (66 per cent). Median overall survival (OS) was 14.7 (95 per cent c.i. 12.7 to 17.3) months in the PCC group versus 21.2 (14.7 to 36.4) months in the non-PCC group (P Conclusion In selected patients, CRS-HIPEC offers acceptable outcomes among those with gastric PCC and long survival for patients without PCC.

A group of experts from the Peritoneal Surface Oncology Group International (PSOGI) and the BIG-RENAPE group carried out a consensus among surgeons experienced in treating peritoneal malignancies from around the world to derive recommendations on indications of hyperthermic intraperitoneal chemotherapy (HIPEC), choice and details of HIPEC regimens, and areas for future research. This manuscript describes the methodology of achieving this consensus and the degree of participation of experts.The Delphi technique was used and the questionnaire comprised three categories: evidence-based recommendations using the GRADE (Grades of Recommendation, Assessment, Development, and Evaluation) system with the PICO (patient, intervention, comparison, and outcome) method, an opinion survey, and research recommendations. A consensus was achieved if any one option had50% of votes, or positive or negative recommendations combined had 70% of votes.Of the 145 experts solicited, 71.1% in round I and 72.2% in round II took the survey. Participation was highest among surgeons treating both gastrointestinal and gynecological malignancies. Of 113 questions, after round I, a consensus was achieved for 72 (63.7%) questions, and after the second round, consensus was achieved for another 22 (19.4%) questions, making a total of 94 (83.1%) questions for which a consensus was achieved.This consensus was carried out using a thorough review of literature and robust rating of evidence, and included key experts and opinion leaders from across the world. The results could guide clinicians on the use of HIPEC, both in their day-to-day clinical practice and in designing clinical trials.

Epithelioid mesothelioma is the most prevalent subtype of diffuse malignant peritoneal mesothelioma. A recently described nuclear-grading system predicted survival in patients with epithelioid malignant pleural mesothelioma. The present study was undertaken to validate this grading system in epithelioid malignant peritoneal mesothelioma (EMPM) and to compare to combined grade, including nuclear atypia, mitotic count, and tumor necrosis. Cases of EMPM, from 1995 to 2018, were analyzed from 7 French institutions from RENAPE network. Solid growth, tumor necrosis, nuclear atypia, and mitotic count were evaluated by at least 3 pathologists from the RENAPATH group. The predictions in terms of OS and PFS of nuclear grade and combined grade were analyzed. Nuclear grade was computed combining nuclear atypia score and mitotic count into a grade of I–III. Another system combining nuclear atypia score, mitotic score, and tumor necrosis was evaluated and defined as a combined grade I–III. A total of 138 cases were identified. The median follow-up was 38.9 months (range: 1.1–196.6). Nuclear and combined grades III were independently associated with a shorter OS (p

Epithelioid mesothelioma is the most prevalent subtype of diffuse malignant peritoneal mesothelioma. The relationship between a strong adaptive immune response and a better prognosis in malignant solid tumors is widely known. Due to the low incidence of epithelioid malignant peritoneal mesothelioma (EMPM), very little is known about their immune micro-environment. We encountered several cases of tertiary lymphoid structures in EMPM in a previous study and aimed to investigate in the same series the prevalence, clinicopathological features, and the prognostic impact associated with tertiary lymphoid structures in EMPM (TLS-EMPM). Cases of EMPM, from 1995 to 2018, were retrieved from 7 French institutions from the RENAPE Network. The predictions in terms of overall survival (OS) and progression-free survival (PFS) of TLS-EMPM were analyzed. We report 52 cases of TLS-EMPM among a series of 138 cases of EMPM. TLS-EMPM was significantly associated with neoadjuvant chemotherapy, and was not a prognostic indicator for OS (p = 0.652) and PFS (p = 0.804) in our series. TLS is a component of the host immune response to EMPM significantly associated with neoadjuvant chemotherapy, but was not a predictor of prognosis for overall and progression-free survivals in this series. These findings provide another possible etiology for tertiary lymphoid structures.

Background Multimodal treatment, including systemic treatment and surgery, improved the prognosis of peritoneal metastasis (PM). Despite all efforts, recurrence rates remain high, and little data are available about clinical behavior or molecular patterns of PM in comparison to hematogenous metastasis. Here, we aimed to analyze recurrence patterns after multimodal treatment for PM from colorectal cancer. Methods Patients with colorectal PM undergoing multimodal treatment including systemic chemotherapy and cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) between 2005 and 2017 at 4 centers were analyzed retrospectively. Results A total of 505 patients undergoing CRS/HIPEC were analyzed. Of the patients, 82.1% received preoperative chemotherapy. Median peritoneal cancer index was 6 (interquartile range = 3-11). Median disease-free and overall survival was 12 (95% confidence interval [CI] = 11 to 14) months and 51 (95% CI = 43 to 62) months, respectively. Disease recurred in 361 (71.5%) patients, presenting as isolated peritoneal recurrence in 24.6%, isolated hematogenous recurrence in 28.3%, and mixed recurrence in 13.9% of patients. Recurrence to the peritoneum was associated with an impaired time from recurrence to death of 21 (95% CI = 18 to 31) months for isolated peritoneal and 22 (95% CI = 16 to 30) months for mixed recurrence, compared with 43 (95% CI = 31 to >121) months for hematogenous recurrence (hazard ratio [HR] = 1.79, 95% CI = 1.27 to 2.53; P = .001; and HR = 2.44, 95% CI = 1.61 to 3.79; P Conclusions This study highlights the heterogeneity of peritoneal metastasis in patients with colorectal cancer. Recurrent peritoneal metastasis after radical treatment represents a more aggressive subset of metastatic colorectal cancer.

Background PIPAC is a recent method of intraperitoneal chemotherapy. The aim of this study was to describe the clinical characteristics of the patients who became amenable to CRS & HIPEC after PIPAC treatment. Methods All patients diagnosed with unresectable PM who became resectable throughout PIPAC treatment were included. Outcome criteria were adverse events following PIPAC procedure and rate of secondary CRS and HIPEC. Results Four hundred thirty-seven PIPAC were done in 146 consecutive patients. Among them, 26 patients (17.8%) who underwent 76 PIPAC were scheduled for CRS and HIPEC after reduction of the peritoneal burden. PM were from gastric, peritoneal mesothelioma, ovarian, colorectal and small bowel in 13, 7, 4, 1 and 1 patients, respectively. At the time of the first PIPAC, median age was 58.6 years (32–76.3). Median PCI was 16 (1–39). All patients had systemic chemotherapy in between PIPAC session. Median consecutive PIPAC procedure was 3 (1–8). Complications occurred in 3 PIPAC session (4%) and there was no major complication (CTCAE III or higher). Complete CRS and HIPEC was achieved in 21 patients of the 26 scheduled (14.4%). The remaining 5 patients were considered unresectable at the exploratory laparotomy. Among patients who underwent CRS and HIPEC, with median follow-up of 7 (1–26) months, 14 patients (66.7%) were alive without recurrence, 2 patients (9.5%) were alive with recurrence and 5 patients (23.8%) died. Conclusions Complete CRS and HIPEC can be achieved in strictly selected patient with unresectable PM at diagnosis after repeated PIPAC session with palliative intent.

Background Multicystic peritoneal mesothelioma (MCPM) is a rare, slowly growing, condition prone to recur after surgery. The role of hyperthermic intraperitoneal chemotherapy (HIPEC) added to complete cytoreductive surgery (CRS) remains controversial and difficult to assess. As patients are mostly reproductive age women, surgical approach, and fertility considerations are important aspects of the management. This observational retrospective review aimed to accurate treatment strategy reflections. Methods The RENAPE database (French expert centers network) was analyzed over a 1999–2019 period. MCPM patients treated with CRS were included. A special focus on HIPEC, mini-invasive approach, and fertility considerations was performed. Results Overall 60 patients (50 women) were included with a median PCI of 10 (4–14) allowing 97% of complete surgery, followed by HIPEC in 82% of patients. A quarter of patients had a laparoscopic approach. Twelve patients (20%) recurred with a 3-year recurrence free survival of 84.2% (95% confidence interval 74.7–95.0). The hazard of recurrence was numerically reduced among patients receiving HIPEC, however, not statistically significant (hazard ratio 0.41, 0.12–1.42, p = 0.200). A severe post-operative adverse event occurred in 22% of patients with five patients submitted to a subsequent reoperation. Among four patients with a childbearing desire, three were successful (two had a laparoscopic-CRS-HIPEC and one a conventional CRS without HIPEC). Conclusion MCPM patients treatment should aim at a complete CRS. The intraoperative treatment options as laparoscopic approach, fertility function sparing and HIPEC should be discussed in expert centers to propose the most appropriate strategy.

Background Enhanced recovery after surgery (ERAS) pathways have been shown to considerably reduce complications, length of stay and costs after most of surgical procedures by standardised application of best evidence-based perioperative care. The aim was to elaborate dedicated recommendations for cytoreductive surgery (CRS) ± hyperthermic intraperitoneal chemotherapy (HIPEC) in a two-part series of guidelines based on expert consensus. The present part I of the guidelines highlights preoperative and intraoperative management. Methods The core group assembled a multidisciplinary panel of 24 experts involved in peritoneal surface malignancy surgery representing the fields of general surgery (n = 12), gynaecological surgery (n = 6), and anaesthesia (n = 6). Experts systematically reviewed and summarized the available evidence on 72 identified perioperative care items, following the GRADE (grading of recommendations, assessment, development, evaluation) system. Final consensus (defined as ≥50%, or ≥70% of weak/strong recommendations combined) was reached by a standardised 2-round Delphi process, regarding the strength of recommendations. Results Response rates were 100% for both Delphi rounds. Quality of evidence was evaluated high, moderate low and very low, for 15 (21%), 26 (36%), 29 (40%) and 2 items, respectively. Consensus was reached for 71/72(98.6%) items. Strong recommendations were defined for 37 items, No consensus could be reached regarding the preemptive use of fresh frozen plasma. Conclusion The present ERAS recommendations for CRS±HIPEC are based on a standardised expert consensus process providing clinicians with valuable guidance. There is an urgent need to produce high quality studies for CRS±HIPEC and to prospectively evaluate recommendations in clinical practice.

Peritoneal carcinomatosis from appendiceal goblet cell carcinoma (A-GCC) is a rare and aggressive form of appendiceal tumor. Cytoreductive surgery (CRS) and hyperthermic intra peritoneal chemotherapy (HIPEC) was reported as an interesting alternative regarding survival compared to surgery without HIPEC and/or systemic chemotherapy. Our aim was to evaluate the impact of CRS and HIPEC for patients presenting A-GCC through an international registry.A prospective multicenter international database was retrospectively searched to identify all patients with A-GCC tumor and peritoneal metastases who underwent CRS and HIPEC through the Peritoneal Surface Oncology Group International (PSOGI). The post-operative complications, long-term results, and principal prognostic factors were analyzed.The analysis included 83 patients. After a median follow-up of 47 months, the median overall survival (OS) was 34.6 months. The 3- and 5-year OS was 48.5% and 35.7%, respectively. Patients who underwent complete macroscopic CRS had a significantly better survival than those treated with incomplete CRS. The 5-year OS was 44% and 0% for patients who underwent complete, and incomplete CRS, respectively (HR 9.65, p 0.001). Lymph node involvement and preoperative chemotherapy were also predictive of a worse prognosis. There were 3 postoperative deaths, and 30% of the patients had major complications.CRS and HIPEC may increase long-term survival in selected patients with peritoneal metastases of A-GCC origin, especially when complete CRS is achieved. Ideally, randomized control trials or more retrospective data are needed to confirm CRS and HIPEC as the gold standard in this pathology.

(1) Background: Peritoneal metastasis in gastric cancer is associated with a poor prognosis. Complete cytoreductive surgery including gastrectomy and complete removal of all peritoneal lesions followed by hyperthermic intraperitoneal chemotherapy (HIPEC) achieves promising results. There exists an immersive variety of approaches for HIPEC that makes it difficult to weigh different results obtained in the literature. In order to enable standardization and development of HIPEC, we here present a systematic review of different drug regimens and technical approaches. (2) Methods: PubMed, Embase, and the Cochrane Library were systematically searched on 26 May 2021 using the mesh terms “intraperitoneal chemotherapy AND gastric cancer”. Under consideration of systematic review guidelines, articles reporting on HIPEC in combination with CRS were selected. Data on duration, drugs, dosage, and other application parameters as well as morbidity and long term survival data were extracted for subsequent statistical analysis, tabulation, and descriptive synthesis. We assessed the risk of bias due to inhomogeneity of the patient cohort and incompleteness of report of HIPEC parameters. (3) Results: Out of 1421 screened publications, 42 publications presenting data from 1325 patients met the criteria. Most of the publications were single institutional retrospective cohort studies. The most common HIPEC regimen is performed after gastrointestinal anastomosis and consists of 50–200 mg/m2 cisplatinum and 30–40 mg/m2 mytomycin C at 42–43 °C for 60–90 min in a closed abdomen HIPEC system with three tubes. Almost every study reported incompletely on HIPEC parameters. Lower rates of anastomotic leakage were reported in studies that performed HIPEC after gastrointestinal anastomosis. Studies that performed open HIPEC and integrated a two-drug regimen indicated better overall survival rates. (4) Discussion: This is an exhaustive overview of the use of drug regimens and techniques for HIPEC after CRS for gastric cancer peritoneal metastasis. Other indications and application modes of intraperitoneal chemotherapy such as prophylactic or palliative HIPEC apart from CRS were not addressed. (5) Conclusion: Complete report of HIPEC parameters should be included in every publication. A consensus for dose expression either per BSA or as flat dose is desirable for comparison of the drug regimens. Despite numerous variations, we identified the most common regimens and techniques and their advantages and disadvantages according to the data in the literature. More phase I/II studies are needed to identify the best approach for HIPEC. (6) Other: This review was not supported by third parties.

Objectives Safe implementation and thorough evaluation of new treatments require prospective data monitoring and standardization of treatments. Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a promising alternative for the treatment of patients with peritoneal disease with an increasing number of suggested drug regimens. The aim was to reach expert consensus on current PIPAC treatment protocols and to define the most important research topics. Methods The expert panel included the most active PIPAC centers, organizers of PIPAC courses and principal investigators of prospective studies on PIPAC. A comprehensive literature review served as base for a two-day hybrid consensus meeting which was accompanied by a modified three-round Delphi process. Consensus bar was set at 70% for combined (strong and weak) positive or negative votes according to GRADE. Research questions were prioritized from 0 to 10 (highest importance). Results Twenty-two out of 26 invited experts completed the entire consensus process. Consensus was reached for 10/10 final questions. The combination of doxorubicin (2.1 mg/m2) and cisplatin (10.5 mg/m2) was endorsed by 20/22 experts (90.9%). 16/22 (72.7%) supported oxaliplatin at 120 with potential reduction to 90 mg/m2 (frail patients), and 77.2% suggested PIPAC-Ox in combination with 5-FU. Mitomycin-C and Nab-paclitaxel were favoured as alternative regimens. The most important research questions concerned PIPAC conditions (n=3), standard (n=4) and alternative regimens (n=5) and efficacy of PIPAC treatment (n=2); 8/14 were given a priority of ≥8/10. Conclusions The current consensus should help to limit heterogeneity of treatment protocols but underlines the utmost importance of further research.

PIPAC (Pressurized IntraPeritoneal Aerosol Chemotherapy) is a minimally invasive approach relying on physical principles for improving intraperitoneal drug delivery, including optimizing the homogeneity of drug distribution through an aerosol. Feasibility and safety of the new approach are now consolidated and data on its effectiveness are continuously increasing. Although any surgical procedure associated with PIPAC had always been discouraged due to the high risk of complications, surgical practice is constantly changing: with growing expertise, more and more surgical teams associate PIPAC with surgery. PLUS study is part of the retrospective international cohort studies including 10 centers around the world (India, Italy, France, Germany, Belgium, Russia, Saudi Arabia, Switzerland) and 96 cases of combined approaches evaluated through a propensity score analysis. the procedures most frequently associated with PIPAC were not only adhesiolysis, omentectomy, adnexectomy, umbilical/inguinal hernia repairs, but also more demanding procedures such as intestinal resections, gastrectomy, splenectomy, bowel repair/stoma creation. Although the evidence is currently limited, PLUS study demonstrated that PIPAC associated with additional surgical procedures is linked to an increase of surgical time (p < 0.001), length of stay (p < 0.001) and medical complication rate (p < 0.001); the most frequently reported medical complications were mild or moderate in severity, such as abdominal pain, nausea, ileus and hyperthermia. No difference in terms of surgical complications was registered; neither reoperation or postoperative deaths were reported. these results suggest that PIPAC can be safely combined in expert centers with additional surgeries. Widespread change of practice should be discouraged before the results of ongoing prospective studies are available.

Objective Diffuse malignant peritoneal mesothelioma (DMPM), represents 30% of all malignant mesothelioma, and is characterised by a difficult diagnosis and different presentations. Immunohistochemistry has improved the diagnostic sensitivity and specificity in the differential diagnosis between metastatic adenocarcinoma and malignant mesothelioma, and loss of BRCA-1-associated protein 1 (BAP1) expression is correlated with BAP1 somatic or constitutional genetic defects. Furthermore, cyclin-dependent kinase inhibitor 2A (CDKN2A) is frequently lost in DMPM. In the present study, we assessed the value of integrating BAP1 in the panel of antibodies used for the diagnosis of DMPM in cytological samples. Since p16 fluorescent in situ hybridisation (FISH) assay could constitute an additional useful adjunct, results of BAP1 immunostaining and p16 FISH assays have been compared. Methods Forty-eight DMPM patients and 71 peritoneal carcinomatosis patients were included. BAP1 immunohistochemical and CDKN2A FISH techniques were performed on tissue specimens of DMPM (n = 48) and peritoneal carcinomatosis (n = 71) then on cell-block of DMPM (n = 16), peritoneal carcinomatosis (n = 25) and peritoneal benign effusion (n = 5). Results Loss of BAP1 expression was observed in 56.3% of DMPM while none of the peritoneal carcinoma specimens showed BAP1 loss of expression. CDKN2A loss was observed in 34.9% DMPM and 2.1% peritoneal carcinoma. Although BAP1 immunostaining was successful in 100% of cytological DMPM samples, CDKN2A deletion status could be obtained for 75% of DMPM cases. Conclusion BAP1 immunostaining represents an objective and reproducible diagnostic biomarker for peritoneal mesothelioma in effusion cytology specimens and should be preferred to CDKN2A FISH analysis on these precious samples.

SCOPUS: ar.j, info:eu-repo/semantics/published

Recent technological advances coupled with our improved understanding of the molecular and cellular mechanisms associated with cancer development have enabled better overall patient care. Among the newly identified biomarkers such as circulating tumor DNA or circulating tumor cells, hPG

Introduction/Background* In patients with gestational trophoblastic tumors (GTT) with a FIGO score ≥ 7, or GTT resistant to both standard monotherapies, the recommended polychemotherapy regimen is EMA-CO. In case of resistance to polychemotherapy, the prognosis is poor. The anti-PD-L1 monoclonal antibody avelumab may be effective for GTT resistant to monochemotherapy (You et al JCO 2020). The efficacy data of avelumab in patients with GTT resistant to polychemotherapy enrolled in cohort B of TROPHIMMUN trial (NCT03135769) are presented. Methodology In cohort B, patients with GTT resistant to polychemotherapy received avelumab 10 mg/kg Q2W until hCG normalization, and for 3 additional cycles thereafter. The primary endpoint was the rate of patients with hCG normalization, following a 2-step Simon design. The cohort was closed prematurely for futility. Result(s)* 2017-2020 : seven patients were treated with the French Gestational Trophoblastic Center (median age was 37 ; choriocarcinoma: 4; placental-site: 1; epithelioid: 1; other: 1) ; stage I/III: 43%/57%; FIGO score 8-10: 43%; score 11-15: 57%. Patients had experienced previous failures to monochemotherapy (n=5), pelvis surgery (n=2), and polychemotherapy (EMA-CO, n=5; EMA-EP, n=1; TP/TE, n=1; APE; n=1). They received a median of 6 avelumab cycles (range: 3-13). Six (85.7%) patients achieved initial hCG stabilization/decline, and one patient (14.2%) had successful hCG normalization after 13 cycles. Another patient experienced favorable hCG decline, but avelumab was discontinued for hemostatic hysterectomy, followed by sustained hCG normalization. The 5 other patients (71.4%) experienced hCG re-increase suggesting avelumab resistance, including two patients who developed brain hemorrhage after 4 cycles (brain metastases in one patient; arteriovenous malformation in one patient who died). The 4 remaining patients were subsequently treated with hysterectomy, other polychemotherapy, including high-dose/bone-marrow-transplant for two; pembrolizumab for one (who died). Conclusion* TROPHIMMUN is the first trial of immunotherapy in GTT. Contrarily to avelumab suggested effectiveness in patients with monotherapy resistance (Cohort A), avelumab activity was limited in patients with polychemotherapy resistance. Despite initial changes in hCG kinetics in most patients, eventual hCG normalization was rare (14%). The prognosis of patients experiencing polychemotherapy resistance remains poor. Combination treatments with immunotherapy should be considered.

Almost two in three patients who are aged 75 years and older and scheduled for surgery for colorectal cancer (CRC) are undernourished. Despite evidence that perioperative nutritional management can improve patients outcomes, international guidelines are still insufficiently applied in current practice. In this stepped-wedge cluster-randomized study of five surgical hospitals, we included 147 patients aged 70 years or older with scheduled abdominal surgery for CRC between October 2013 and December 2016. In the intervention condition, an outreach team comprising a geriatrician and a dietician visited patients and staff in surgical wards to assist with the correct application of guidelines. Evaluation, diagnosis, and prescription (according to nutritional status) were considered appropriate and strictly consistent with guidelines in 39.2% of patients in the intervention group compared to only 1.4% in the control group (p = 0.0002). Prescription of oral nutritional supplements during the perioperative period was significantly improved (41.9% vs. 4.1%; p < 0.0001). However, there were no benefits of the intervention on surgical complications or adverse events. A possible benefit of hospital stay reduction will need to be confirmed in further studies. This study highlights the importance of the implementation of quality improvement interventions into current practice for the perioperative nutritional management of older patients with CRC.

IntroductionDespite optimal patient selection and surgical effort, recurrence is seen in over 70% of patients undergoing cytoreductive surgery (CRS) for peritoneal metastases (PM). Apart from the Peritoneal Cancer Index (PCI), completeness of cytoreduction and tumour grade, there are other factors like disease distribution in the peritoneal cavity, pathological response to systemic chemotherapy (SC), lymph node metastases and morphology of PM which may have prognostic value. One reason for the underutilisation of these factors is that they are known only after surgery. Identifying clinical predictors, specifically radiological predictors, could lead to better utilisation of these factors in clinical decision making and the extent of peritoneal resection performed for different tumours. This study aims to study these factors, their impact on survival and identify clinical and radiological predictors.Methods and analysisThere is no therapeutic intervention in the study. All patients with biopsy-proven PM from colorectal, appendiceal, gastric and ovarian cancer and peritoneal mesothelioma undergoing CRS will be included. The demographic, clinical, radiological, surgical and pathological details will be collected according to a prespecified format that includes details regarding distribution of disease, morphology of PM, regional node involvement and pathological response to SC. In addition to the absolute value of PCI, the structures bearing the largest tumour nodules and a description of the morphology in each region will be recorded. A correlation between the surgical, radiological and pathological findings will be performed and the impact of these potential prognostic factors on progression-free and overall survival determined. The practices pertaining to radiological and pathological reporting at different centres will be studied.Ethics and disseminationThe study protocol has been approved by the Zydus Hospital ethics committee (27 July, 2020) and Lyon-Sud ethics committee (A15-128).Trial registration numberCTRI/2020/09/027709; Pre-results.

International audience; Almost two in three patients who are aged 75 years and older and scheduled for surgery for colorectal cancer (CRC) are undernourished. Despite evidence that perioperative nutritional management can improve patients outcomes, international guidelines are still insufficiently applied in current practice. In this stepped-wedge cluster-randomized study of five surgical hospitals, we included 147 patients aged 70 years or older with scheduled abdominal surgery for CRC between October 2013 and December 2016. In the intervention condition, an outreach team comprising a geriatrician and a dietician visited patients and staff in surgical wards to assist with the correct application of guidelines. Evaluation, diagnosis, and prescription (according to nutritional status) were considered appropriate and strictly consistent with guidelines in 39.2% of patients in the intervention group compared to only 1.4% in the control group (p = 0.0002). Prescription of oral nutritional supplements during the perioperative period was significantly improved (41.9% vs. 4.1%; p < 0.0001). However, there were no benefits of the intervention on surgical complications or adverse events. A possible benefit of hospital stay reduction will need to be confirmed in further studies. This study highlights the importance of the implementation of quality improvement interventions into current practice for the perioperative nutritional management of older patients with CRC.

Diffuse malignant peritoneal mesothelioma (DMPM) is an aggressive primary peritoneal neoplasia. At diagnosis, few patients are eligible for a recommended cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Among neoadjuvant strategies, pressurized intraperitoneal aerosol chemotherapy (PIPAC) combined with systemic chemotherapy has been recently proposed. This study evaluated this strategy in a cohort of DMPM patients.Patients with DMPM and primary or recurrent non-resectable diseases who received at least one PIPAC procedure in alternation with systemic chemotherapy were included in this retrospective study to analyze oncologic outcomes.Overall, 26 DMPM patients were treated with at least one PIPAC, including 20 patients with no previous CRS. Of 22 patients (85%) who had symptoms, 9 had perceptible ascites. Overall, 79 PIPAC procedures were performed, with half of the patients receiving three PIPAC procedures or more. Among eight patients (31%), 10 adverse events (13% of procedures) were reported, including two severe complications, both corresponding to digestive perforations. Improvement of symptoms was reported for 32% of the patients, whereas control of ascites was noted in 46%. All but one procedure among 14 patients (54%) secondarily treated by CRS-HIPEC were considered complete resections. After a median follow-up period of 29.6 months (95% confidence interval [CI], 17.6-not reached [NR]), the median overall survival period was 12 months (95% CI 11.1-NR). The median progression-free survival (PFS) was significantly better among the patients who underwent resection than among those who did not (33.5 vs 7.4 months; hazard ratio [HR], 0.18; 95% CI 0.06-0.755; p0.001).For patients with initially non-resectable DMPM, PIPAC is feasible for treatment with neoadjuvant intent and could facilitate complete secondary resection.