BACKGROUND:Colorectal cancer with peritoneal metastases (PM) presents a significant therapeutic challenge. Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is one option to prolong survival. While completeness of cytoreduction (CC) score 0 is associated with improved outcomes, the clinical value of near-complete CC-score 1 versus open-close laparotomy (CC-3) remains unclear. METHODS:This retrospective study evaluates overall survival (OS) in patients with colorectal cancer PM scheduled for CRS and HIPEC from 23 global peritoneal-surface oncology centers from 2006 to 2023. A propensity score matching was performed using tumor location (colon/rectum), lymph node status, liver metastases, signet-ring histology, preoperative chemotherapy, peritoneal cancer index, and treatment year. Matching was performed using the nearest neighbor method with a caliper of 0.1, chosen after several iterations to optimize intergroup balance. Balance was assessed using standardized mean differences. Sensitivity analyses with alternative calipers and multivariable Cox regression in the unmatched cohort were considered to test the robustness of the findings. The study time-period was divided into 4 equal quartiles for analysis. RESULTS:In the unmatched cohort (n = 284), patients with CC-1 had significantly longer median OS compared to those with CC-3 (22.2 vs. 9.4 months, p < 0.001). After 1:1 matching (n = 172), the OS advantage of CC-1 persisted, with a median OS of 18.9 months (95 % CI: 14.2-24.7) versus 10.5 months (95 % CI: 9.4-12.3) for CC-3, p < 0.0001, HR 0.4 (95 % CI:0.27-0.56). Multivariable Cox regression confirmed CC-1 as a significant predictor of survival (HR: 0.15, 95 % CI: 0.08-0.26). The CC-1 proportion went from 55 to 65 % in time-periods 1 & 2-39 % in period 3, to 11 % in period 4; leading to significantly reduced survival rates in the latter time-periods 3 & 4. DISCUSSION:Near complete cytoreduction is associated with improved overall survival compared to open-close laparotomy. Prospective or standardized multicenter analyses will be required to confirm the clinical value of a near complete cytoreduction.

BACKGROUND:No guidelines exist regarding the management of the uninvolved uterus or adnexa (fallopian tubes and/or ovaries) in patients with peritoneal metastases (PM) from non-gynecologic malignancies. It is unclear whether salpingo-oophorectomy, hysterectomy, or both should be performed when a complete pelvic peritonectomy is otherwise warranted. METHODS:A 25-item electronic survey was sent to 225 surgeons worldwide who routinely perform cytoreductive surgery (CRS) plus hyperthermic intraperitoneal chemotherapy (HIPEC). Participants were recruited through listservs of expert groups. Individual surgeon approaches to the management of the grossly uninvolved uterus and adnexa in pre- and post-menopausal women with PM from low- and high-grade appendiceal neoplasms, colorectal cancer, and peritoneal mesothelioma were collected using a 5-point Likert scale. RESULTS:A total of 135 complete responses (60% response rate) were obtained from surgeons practicing in 27 countries. Respondents reported a median practice of 10 years (interquartile range [IQR] 6-15 years) and a median performance of 20 (IQR 12-30) CRS/HIPEC operations per year. Rates of salpingo-oophorectomy differed by histology and a woman's menopausal status, ranging from 29 to 42% in pre-menopausal women to 71-77% in post-menopausal women (P < 0.001). Notably, the number of surgeons who would perform a hysterectomy was lower, ranging from 12 to 27% for pre-menopausal women and from 32 to 44% for post-menopausal women, dependent on histology (P < 0.001). CONCLUSIONS:Surgeons are overall more aggressive with adnexal resection than with hysterectomy in both pre- and post-menopausal women with PM from non-gynecologic malignancies. Further prospective studies are required to determine the best approach to optimize surgical and oncologic outcomes while also accounting for the fertility and hormonal impact.

Background: Increasing data suggests that the combination of modern systemic therapies and Cytoreductive surgery with or without Hyperthermic Intraperitoneal Chemotherapy (HIPEC) may improve the outcome of patients with colon cancer with peritoneal metastases. Patient selection and sequence of treatments remains ill-defined.Materials and methods: A working group, the State of Delaware Peritoneal Surface Malignancies Task Force (DE-PSM-TF), was created including representatives from medical and surgical oncology from the acute care hospitals in Delaware. An extensive review of all available literature was carried out. Virtual meetings were held, and interpretation and discussion of the data was conducted.Results: A clinical pathway that includes a multidisciplinary evaluation at the time of diagnosis of colon cancer with peritoneal metastases and reflects a consensus from the Task Force on 7 key points that suggest the management of these patients based on the severity of their peritoneal metastases and incorporates all currently available therapies was created. The sequence of therapies of this multimodality treatment was determined by the Peritoneal Surface Disease Severity Score (PSDSS) (Fig. 1).Conclusion: The current pathway represents a comprehensive, team effort that should improve the outcome of patients with Colon Cancer with peritoneal metastases in the state of Delaware by having multidisciplinary discussions at the time of diagnosis, selecting the best order of sequence of currently available therapies in order to maximize benefits and minimize morbidity.

The laparoscopic approach for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (L-CRS + HIPEC) in highly selected patients was previously reported from the PSOGI registry with a demonstrable reduction in length of stay and post-operative morbidity. This study aims to update this international PSOGI registry with a larger cohort of patients and a longer follow-up period. METHODS:An international registry was designed through a networking database (REDCAP®). All centers performing L-CRS + HIPEC were invited through PSOGI to submit data on their cases. Variables such as demographics, clinical outcomes, and survival were analyzed. RESULTS:A total of 315 L-CRS + HIPEC cases were provided by 14 worldwide centers. A total of 215 patients were included in the L-CRS + HIPEC group. The median peritoneal cancer index (PCI) was 3 (3-5). The median length of stay was 7 days (5-10) and the major morbidity (Clavien-Dindo ≥3) was 6.1% after 30 days. The 5-year disease-free survival (DFS) per tumor origin was: 94% for PMP-LG, 85% for PMP-HG, 100% for benign multicyst peritoneal mesothelioma (MPM), 37.4% for colonic origin, and 54%(at 3 years) for ovarian origin. The 5 years overall survival (OS) per tumor origin was: 100% for PMP-LG, PMP-HG and MPM; 61% for colonic origin, and 74% (at 3 years) for ovarian origin. In addition, a total of 85 patients were analyzed in the laparoscopic risk-reducing HIPEC (L-RR + HIPEC). The median length of stay was 5 days (4-6) and the major morbidity was 6% after 30 days. The 5-year DFS per tumor origin was: 96% for perforated low grade appendiceal mucinous neoplasm (LAMN II) and 68.1% for colon origin. The 5 years OS per tumor origin was: 98% for LAMN II and 83.5% for colonic origin. CONCLUSIONS:Minimally invasive CRS + HIPEC is a safe procedure for selected patients with peritoneal carcinomatosis in specialized centers. It improves perioperative results while providing satisfactory oncologic outcomes. L-RR + HIPEC represents a promising strategy that could be evaluated in patients with high risk of developing peritoneal carcinomatosis into prospective randomized trials.

Neoplasms of the vermiform appendix represent 1% of all gastrointestinal tumors, with epithelial and neuroendocrine histological subtypes being the most frequent.When two or more neoplasms with different components originate synchronically in the appendix with clear margin between them, it is called a collision tumor, with exceptional cases being reported in literature.The purpose is to present two new cases of collision tumors of the appendix and perform a review of the published literature.Two cases of an 82-year-old female and a 41-year-old male with collision tumors of the vermiform appendix are presented, with clinical presentation, radiological evaluation and surgical treatment exposed.Our results are compared with other published reports.In accordance with the other reported cases, both patients presented with low-grade appendiceal mucinous neoplasm (LAMN).Female patient with synchronous goblet cell carcinoma managed with a completion right colectomy and Hyperthermic intraperitoneal chemotherapy (HIPEC) and the other patient with well-differentiated neuroendocrine (NET) tumor managed with laparoscopic appendectomy without adjuvant treatment.Since very few cases have been reported, no diagnostic and therapeutic consensus and guidelines exist up to date.We agree that local, regional, and systemic therapies should be chosen according to the tumor that represents the worst prognosis.

Background There is a paucity of studies evaluating perioperative systemic chemotherapy in conjunction with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with colorectal cancer peritoneal metastases (CRCPM). The aim was to evaluate neoadjuvant and/or adjuvant systemic therapy in CRCPM. Methods Patients with CRCPM from 39 treatment centres globally from January 1, 1991, to December 31, 2018, who underwent CRS+HIPEC were identified and stratified according to neoadjuvant/adjuvant use. Crude data analysis, propensity score matching (PSM) and Cox-proportional hazard modelling was performed. Findings Of 2093 patients, 1613 were included in neoadjuvant crude evaluation with 708 in the PSM cohort (354 patients/arm). In the adjuvant evaluation, 1176 patients were included in the crude cohort with 778 in the PSM cohort (389 patients/arm). The median overall survival (OS) in the PSM cohort receiving no neoadjuvant vs neoadjuvant therapy was 37.0 months (95% CI: 32.6-42.7) vs 34.7 months (95% CI: 31.2-38.8, HR 1.08 95% CI: 0.88-1.32, p = 0.46). The median OS in the PSM cohort receiving no adjuvant therapy vs adjuvant therapy was 37.0 months (95% CI: 32.9-41.8) vs 45.7 months (95% CI: 38.8-56.2, HR 0.79 95% CI: 0.64-0.97, p = 0.022). Recurrence-free survival did not differ in the neoadjuvant evaluation but differed in the adjuvant evaluation - HR 1.04 (95% CI: 0.87-1.25, p = 0.66) and 0.83 (95% CI: 0.70-0.98, p = 0.03), respectively. Multivariable Cox-proportional hazard modelling in the crude cohorts showed hazard ratio 1.08 (95% CI: 0.92-1.26, p = 0.37) for administering neoadjuvant therapy and 0.86 (95% CI: 0.72-1.03, p = 0.095) for administering adjuvant therapy. Interpretation Neoadjuvant therapy did not confer a benefit to patients undergoing CRS+HIPEC for CRCPM, whereas adjuvant therapy was associated with a benefit in this retrospective setting. Copyright (C) 2022 The Author(s). Published by Elsevier Ltd.

INTRODUCTION:A laparoscopic approach for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (L-CRS+HIPEC) in highly selected patients has been reported in small cohorts with a demonstrable reduction in length of stay and post-operative morbidity. This study aims to analyse individual patient data from these international centres collected through the Peritoneal Surface Oncology Group International (PSOGI) L-CRS+HIPEC registry.METHODS:An international registry was designed through a networking database (REDCAP®). All centres performing L-CRS+HIPEC were invited through PSOGI to submit data on their cases. Patient's characteristics, postoperative outcomes and survival were analysed.RESULTS:Ten international centres contributed a total of 143 L-CRS+HIPEC patients during the study period. The most frequent indication was low grade pseudomyxoma peritonei in 79/143 (55%). Other indications were benign multicyst mesothelioma in 21/143(14%) and peritoneal metastasis from colon carcinoma in 18/143 (12,5%) and ovarian carcinoma in 13/143 (9%). The median PCI was 3 (2-5). The median length of stay was 6 (5-10) days, with 30-day major morbidity rate of 8.3% and 30-day mortality rate of 0.7%. At a median follow-up of 37 (16-64) months 126/143 patients (88.2%) were free of disease.CONCLUSIONS:Analysis of these data demonstrates that L-CRS+HIPEC is a safe and feasible procedure in highly selected patients with limited peritoneal disease when performed at experienced centres. While short to midterm outcomes are encouraging in patients with less invasive histology, longer follow up is required before recommending it for patients with more aggressive cancers with peritoneal dissemination.

Introduction: A practical staging classification that has prognostic significance in mucinous appendiceal neoplasms represents an unmet need in oncology.The purpose of this study is to present a second edition of the PSDSS in mucinous appendiceal neoplasms with or without peritoneal dissemination based on the AJCC/TNM 8 th edition.Materials and Methods: We analyzed 229 patients based on the AJCC/TNM 8 th edition incorporating G (grade) and E (extent of disease).The impact of these 5 clinicopathological variables (T, N, M, G, E) is scored as stages 0 to IV and is reported as the Esquivel Peritoneal Surface Disease Severity Score (E-PSDSS).Results: One hundred and seventy-three patients underwent cytoreductive surgery (CRS) and HIPEC.There were 30 (13.1%), 56 (24.4%),48 (20.9%), 20 (8.7%) and 75 (32.7%)patients with E-PSDSS 0, I, II, III, and IV, respectively.Five-year overall survival was 100%, 100%, 84.46%, 52.29% and 12.92% for E-PSDSS 0, I, II, III and IV, respectively (p < 0.0001).On multivariate analysis, sex (p = 0.0462) and E-PSDSS stage [0, I, II, III, IV] (HR 0 vs IV NR, HR 1 vs IV NR, HR II vs IV 0.072 [95% CI 0.028, 0.189], HR III vs IV 0.353 [95% CI 0.158, 0.791]; p < 0.0001) were identified as independent predictors of survival.Conclusion: The E-PSDSS combines specimen examination and reporting according to the College of American Pathologists with the pTNM requirements from the AJCC staging manual.It represents an important prognostic indicator in patients with mucinous appendiceal neoplasms.

BACKGROUND:Low-grade appendiceal mucinous neoplasms (LAMN) are commonly managed by community surgeons at diagnosis. There is variability in the treatment of LAMN, both by community and specialist providers. We assessed current management practices for LAMN across surgeons with expertise in peritoneal surface malignancies (PSM).METHODS:An online survey was sent to 106 international surgeons specializing in PSM. The survey assessed demographics, favored pre-referral management, and definitive management practices for LAMN.RESULTS:The response rate was 40% (67% USA, 33% international). Respondents had performed a median of 18 (interquartile range [IQR] 7.75-29) HIPEC cases in the last year, of which 10 (IQR 4-20) were for LAMN. Ninety-three percent reported more than half of LAMN referrals had already undergone surgery-an estimated 50% appendectomy and 20% right hemicolectomy (RH). No surgeon respondents supported performing right hemicolectomy before referral. For LAMN confined to the appendix, 86% of respondents would definitively treat with appendectomy. In the presence of mucinous implants, 24% would observe after appendectomy and 76% would proceed with HIPEC. All would perform HIPEC if implants contained tumor cells. When LAMN involved the appendiceal base, 67% of respondents would proceed with partial cecectomy, while 33% favored RH.CONCLUSIONS:Pre-referral management of LAMN is not standardized and 20% of patients were referred to a surgeon who performs CRS/HIPEC after a right hemicolectomy that would not have been recommended. Management of LAMN by surgeons who treat PSM is also variable. Long-term data and identification of prognostic features are necessary to generate consensus on the optimal management of these complex patients.

Peritoneal dissemination of low-grade appendiceal mucinous neoplasms (LAMNs), sometimes referred to as pseudomyxoma peritonei, can result in significant morbidity and mortality. Little is known about the natural history of localized (non-disseminated) LAMNs. The goal of this study was to evaluate the risk of peritoneal recurrence in patients with localized LAMNs. We performed a multi-institutional retrospective review of patients with pathologically confirmed localized LAMNs. Baseline characteristics, pathology, and follow-up data were collected. The primary endpoint was the rate of peritoneal recurrence. We identified 217 patients with localized LAMNs. Median age was 59 years (11–95) and 131 (60%) patients were female. Surgical management included appendectomy for 124 (57.1%) patients, appendectomy with partial cecectomy for 26 (12.0%) patients, and colectomy for 67 (30.9%) patients. Pathology revealed perforation in 46 patients (37.7% of 122 patients with perforation status mentioned in the report), extra-appendiceal acellular mucin (EAM) in 49 (22.6%) patients, and extra-appendiceal neoplastic cells (EAC) in 13 (6.0%) patients. Median follow-up was 51.1 months (0–271). Seven (3.2%) patients developed a peritoneal recurrence, with a median time to recurrence of 14.4 months (2.5–47.0). Seven (15.2%) patients with histologic evidence of perforation had recurrence, versus no patients (0%) without perforation (p < 0.001); five (10.2%) patients with EAM versus two (1.2%) patients without EAM (p = 0.007), and one (7.7%) patient with EAC versus six (2.9%) patients without EAC (p = 0.355) had recurrence. This multi-institutional study represents the largest reported series of patients with localized LAMNs. In the absence of perforation or extra-appendiceal mucin or cells, recurrence was extremely rare; however, patients with any of these pathologic findings require careful follow-up.

The Chicago Consensus Working Group provides multidisciplinary recommendations for the management of colorectal cancer specifically as it relates to the management of peritoneal surface malignancy. These guidelines are developed with input from leading experts, including surgical oncologists, medical oncologists, pathologists, radiologists, palliative care physicians, and pharmacists. These guidelines recognize and address the emerging need for increased awareness in the appropriate management of peritoneal surface disease. They are not intended to replace the quest for higher levels of evidence.

The Chicago Consensus Working Group provides multidisciplinary recommendations for the management of peritoneal mesothelioma. These guidelines are developed with input from leading experts, including surgical oncologists, medical oncologists, pathologists, radiologists, palliative care physicians, and pharmacists. These guidelines recognize and address the emerging need for increased awareness of the appropriate management of peritoneal surface disease. They are not intended to replace the quest for higher levels of evidence.

The Chicago Consensus Working Group provides multidisciplinary recommendations for palliative care specifically related to peritoneal surface malignancies. These guidelines are developed with input from leading experts including surgical oncologists, medical oncologists, gynecologic oncologists, pathologists, radiologists, palliative care physicians, and pharmacists. These guidelines recognize and address the emerging need for increased awareness in the appropriate management of peritoneal surface disease. They are not intended to replace the quest for higher levels of evidence.

The Chicago Consensus Working Group provides multidisciplinary recommendations for the management of peritoneal surface malignancies of various causes. These guidelines are developed with input from leading experts including surgical oncologists, medical oncologists, pathologists, radiologists, palliative care physicians, and pharmacists. These guidelines recognize and address the emerging need for increased awareness of the appropriate management of peritoneal surface disease. They are not intended to replace the quest for higher levels of evidence. This article serves as an introduction to this effort.

The Chicago Consensus Working Group provides multidisciplinary recommendations for the management of neuroendocrine tumors specifically related to the management of peritoneal surface malignancy. These guidelines are developed with input from leading experts, including surgical oncologists, medical oncologists, pathologists, radiologists, palliative care physicians, and pharmacists. These guidelines recognize and address the emerging need for increased awareness in the appropriate management of peritoneal surface disease. They are not intended to replace the quest for higher levels of evidence.

The Chicago Consensus Working Group provides multidisciplinary recommendations for the management of desmoplastic small round cell, breast, and gastrointestinal stromal tumors specifically related to peritoneal surface malignancy. These guidelines are developed with input from leading experts, including surgical oncologists, medical oncologists, pathologists, radiologists, palliative care physicians, and pharmacists. These guidelines recognize and address the emerging need for increased awareness in the appropriate management of peritoneal surface disease. They are not intended to replace the quest for higher levels of evidence.

The Chicago Consensus Working Group provides the following multidisciplinary recommendations for the care of patients with peritoneal surface malignancies. This article focuses on the standards of a peritoneal surface malignancy center, standards of billing and coding, standards of operative reports for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy, standards of cytoreductive surgery training, and standards of intraoperative chemotherapy preparation. These guidelines are developed with input from leading experts, including surgical oncologists, medical oncologists, pathologists, radiologists, palliative care physicians, and pharmacists. These guidelines recognize and address the emerging need for increased awareness in the appropriate management of peritoneal surface disease. They are not intended to replace the quest for higher levels of evidence.

BACKGROUND:The field of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) has suffered from a lack of clinical trials to validate its expanding use. OBJECTIVE:To evaluate published and ongoing clinical trials seeking to better define role of CRS/HIPEC in the treatment of peritoneal surface malignancies. METHODS:Systematic review by PubMed search was performed using terms "Clinical trial," "intraperitoneal chemotherapy," and "HIPEC." ClinicalTrials.gov and EudraCT registries were searched for active clinical trials. Eligibility included CRS/HIPEC trials investigating adult patient populations from published clinical reports and/or trials currently accruing or at completion. RESULTS:Thirteen published trials and 57 active clinical trials were included for review. CONCLUSIONS:Published and ongoing U.S. and international clinical trials for CRS and HIPEC are defining important parameters that include improving patient selection, strategic sequences of treatment, cytoreductive strategies, chemotherapeutics, optimal hyperthermic temperature and timing, and toxicity profiles. Main barriers or limitations to trial development remain patient enrollment, trial design, and oncologic community collaboration. Overall progress is positive with increasing number of clinical trials throughout the world. Collaboration between surgeons and the wider oncologic community will be crucial to validate this important treatment strategy.

Ovarian cancer peritoneal carcinomatosis requires a multimodal-treatment approach. Current treatment considerations are analyzed in this update and include the management of recurrent malignant ascites and the understanding of its pathophysiology, the role of peritoneal washing cytology in detecting peritoneal metastases, capsular invasion and ovarian cancer histologic type, interpretation of pretreatment Ca-125 levels at different time points of ovarian cancer therapeutic management, characteristics of 10-year survivors of high-grade ovarian cancer, and the role of lymphadenectomy in ovarian cancer peritoneal carcinomatosis. This update also includes current considerations on the role of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in ovarian cancer peritoneal carcinomatosis as well as relevant ongoing phase III randomized controlled trial protocols.