Body surface area-based vs concentration-based perioperative intraperitoneal chemotherapy after optimal cytoreductive surgery in colorectal peritoneal surface malignancy treatment: COBOX trial

The 2022 PSOGI International Consensus on HIPEC Regimens for Peritoneal Malignancies: HIPEC Technologies

This manuscript reports the results of an international consensus on technologies of hyperthermic intraperitoneal perioperative chemotherapy (HIPEC) performed with the following goals: To provide recommendations for the technological parameters to perform HIPEC. To identify the role of heat and its application forms in treating peritoneal metastases. To provide recommendations regarding the correct dosimetry of intraperitoneal chemotherapy drugs and their carrier solutions. To identify for each intraperitoneal chemotherapy regimen the best dosimetry and fractionation. To identify areas of future research pertaining to HIPEC technology and regimens. This consensus was performed by the Delphi technique and comprised two rounds of voting. In total, 96 of 102 eligible panelists replied to both Delphi rounds (94.1%) with a consensus of 39/51 questions on HIPEC technical aspects. Among the recommendations that met with the strongest consensus were those concerning the dose of HIPEC drug established in mg/m2, a target temperature of at least 42°C, and the use of at least three temperature probes to pursue hyperthermia. Ninety minutes as the ideal HIPEC duration seemed to make consensus. These results should be considered when designing new clinical trials in patients with peritoneal surface malignancies.

Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for colorectal peritoneal metastases: Where do we stand?

PLAIN LANGUAGE SUMMARY

Patients with colorectal cancer that has spread to the lining of the abdomen (peritoneum) benefit from surgery to remove all the cancer. The addition of certain types of intra-abdominal chemotherapy during surgery improves survival for select patients.

Surgical Options for Peritoneal Surface Metastases from Digestive Malignancies-A Comprehensive Review

The peritoneum is a common site for the dissemination of digestive malignancies, particularly gastric, colorectal, appendix, or pancreatic cancer. Other tumors such as cholangiocarcinomas, digestive neuroendocrine tumors, or gastrointestinal stromal tumors (GIST) may also associate with peritoneal surface metastases (PSM). Peritoneal dissemination is proven to worsen the prognosis of these patients. Cytoreductive surgery (CRS), along with systemic chemotherapy, have been shown to constitute a survival benefit in selected patients with PSM. Furthermore, the association of CRS with hyperthermic intraperitoneal chemotherapy (HIPEC) seems to significantly improve the prognosis of patients with certain types of digestive malignancies associated with PSM. However, the benefit of CRS with HIPEC is still controversial, especially due to the significant morbidity associated with this procedure. According to the results of the PRODIGE 7 trial, CRS for PSM from colorectal cancer (CRC) achieved overall survival (OS) rates higher than 40 months, but the addition of oxaliplatin-based HIPEC failed to improve the long-term outcomes. Furthermore, the PROPHYLOCHIP and COLOPEC trials failed to demonstrate the effectiveness of oxaliplatin-based HIPEC for preventing peritoneal metastases development in high-risk patients operated for CRC. In this review, we discuss the limitations of these studies and the reasons why these results are not sufficient to refute this technique, until future well-designed trials evaluate the impact of different HIPEC regimens. In contrast, in pseudomyxoma peritonei, CRS plus HIPEC represents the gold standard therapy, which is able to achieve 10-year OS rates ranging between 70 and 80%. For patients with PSM from gastric carcinoma, CRS plus HIPEC achieved median OS rates higher than 40 months after complete cytoreduction in patients with a peritoneal cancer index (PCI) ≤6. However, the data have not yet been validated in randomized clinical trials. In this review, we discuss the controversies regarding the most efficient drugs that should be used for HIPEC and the duration of the procedure. We also discuss the current evidence and controversies related to the benefit of CRS (and HIPEC) in patients with PSM from other digestive malignancies. Although it is a palliative treatment, pressurized intraperitoneal aerosolized chemotherapy (PIPAC) significantly increases OS in patients with unresectable PSM from gastric cancer and represents a promising approach for patients with PSM from other digestive cancers.

Advances in the management of peritoneal malignancies

Peritoneal surface malignancies (PSMs) are usually associated with a poor prognosis. Nonetheless, in line with advances in the management of most abdominopelvic metastatic diseases, considerable progress has been made over the past decade. An improved understanding of disease biology has led to the more accurate prediction of neoplasia aggressiveness and the treatment response and has been reflected in the proposal of new classification systems. Achieving complete cytoreductive surgery remains the cornerstone of curative-intent treatment of PSMs. Alongside centralization in expert centres, enabling the delivery of multimodal and multidisciplinary strategies, preoperative management is a crucial step in order to select patients who are most likely to benefit from surgery. Depending on the specific PSM, the role of intraperitoneal chemotherapy and of perioperative systemic chemotherapy, in particular, in the neoadjuvant setting, is established in certain scenarios but questioned in several others, although more prospective data are required. In this Review, we describe advances in all aspects of the management of PSMs including disease biology, assessment and improvement of disease resectability, perioperative management, systemic therapy and pre-emptive management, and we speculate on future research directions.

A phase 2 trial of short-course Hyperthermic IntraPeritoneal Chemotherapy (HIPEC) at interval cytoreductive surgery (iCRS) for advanced ovarian cancer

OBJECTIVE

to report the final analysis of a phase 2 trial assessing the efficacy and safety of short-course hyperthermic intraperitoneal chemotherapy (HIPEC) for patients with advanced epithelial ovarian cancer (EOC).

METHODS

this was an open-label, multicenter, single-arm trial of HIPEC in patients with advanced EOC who underwent interval cytoreductive surgery (iCRS) after neoadjuvant chemotherapy (NACT). HIPEC was performed as a concentration-based regimen of platinum-based chemotherapy for 30 minutes. Primary endpoint was the rate of disease progression occurring at nine months following iCRS plus HIPEC (PD9). Secondary endpoints were postoperative complications, time to start adjuvant chemotherapy, length of hospital and ICU stay, quality of life (QoL) over treatment, and ultimately 2-year progression-free survival (PFS) and overall survival (OS). Analysis was by intention-to-treat with final database lock for survival outcomes on February 23, 2021.

RESULTS

fifteen patients with stage III EOC were enrolled between February 2015 and July 2019, in four centers. The intention to treat PD9 was 6.7%. With a median follow-up of 33 months (IQR, 24.3-46.5), the median PFS was 18.1 months and corresponding 2-year rates of PFS and OS was 33.3% and 93.3%, respectively. Three patients (20%) experienced graded III complications. Median length of hospital and ICU stay was 5 (IQR, 4-6.5) and 1 (IQR, 1-1) days, respectively. Time to restart systemic chemotherapy was 39 (IQR, 35-49.3) days and no significant difference over time in QoL was observed.

CONCLUSIONS

we demonstrate preliminary efficacy and safety of short-course HIPEC in patient with advanced EOC.

The impact of postoperative complications following cytoreductive surgery combined with oxaliplatin based heated intraperitoneal chemotherapy

INTRODUCTION

Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS + HIPEC) has become the mainstream treatment for peritoneal metastases of colorectal origin. This extensive treatment is known for its increased morbidity rate. In this study, the impact of postoperative complications on survival was evaluated in a high-volume centre.

PATIENTS AND METHOD

Between November 2016 through October 2018, all 106 patients with peritoneal metastases of colorectal origin treated with CRS + HIPEC with oxaliplatin were evaluated. Data on patient characteristics, Peritoneal Carcinomatosis Index (PCI), operative procedure, post-operative complications (Clavien-Dindo classification grade III or higher) and survival were collected. In-hospital postoperative complications were analysed for their association with patient characteristics, tumour load (PCI), and operative procedure with logistic regression analyses. Survival was analysed with the Cox regression analysis.

RESULTS

Of 106 patients, 78% had an un-eventful in-hospital recovery. Of those patients who experienced complications, 52% patients had one complication and 48% had more than one. The median follow-up time was 33.8 months. Median survival was 22.4 months (95% CI 12.2-NR) for patients who experienced complications and not reached for those who did not. Survival was significantly associated with complications (HR 2.2, 95% CI 1.2-4.0) as well as with PCI (HR 1.1, 95% CI 1.1-1.2) in univariate analyses. A stepwise Cox regression analysis showed both PCI and complications had an independent negative impact on survival.

CONCLUSION

Postoperative complications, independently of tumour load, led to reduced survival in patients with peritoneal metastases of colorectal origin when treated with CRS + HIPEC with oxaliplatin.

HIPEC Methodology and Regimens: The Need for an Expert Consensus

BACKGROUND

Hyperthermic intraperitoneal chemotherapy (HIPEC) is performed with a wide variation in methodology, drugs, and other elements vital to the procedure. Adoption of a limited number of regimens could increase the collective experience of peritoneal oncologists, make comparison between studies more meaningful, and lead to a greater acceptance of results from randomized trials. This study aimed to determine the possibility of standardizing HIPEC methodology and regimens and to identify the best method of performing such a standardization.

METHODS

A critical review of preclinical and clinical studies evaluating the pharmacokinetic aspects of different HIPEC drugs and drug regimens, the impact of hyperthermia, and the efficacy of various HIPEC regimens as well as studies comparing different regimens was performed.

RESULTS

The preclinical and clinical data were limited, and studies comparing different regimens were scarce. Many of the regimens were neither supported by preclinical rationale or data nor validated by a dose-escalating formal phase 1 trial. All the regimens were based on pharmacokinetic data and did not take chemosensitivity of peritoneal metastases into account. Personalized medicine approaches such as patient-derived tumor organoids could offer a solution to this problem, although clinical validation is likely to be challenging.

CONCLUSIONS

Apart from randomized trials, more translational research and phases 1 and 2 studies are needed. While waiting for better preclinical and clinical evidence, the best way to minimize heterogeneity is by an expert consensus that aims to identify and define a limited number of regimens for each indication and primary site. The choice of regimen then can be tailored to the patient profile and its expected toxicity and the methodology according regional factors.

Hyperthermic intraperitoneal chemotherapy (HIPEC) for colorectal and appendiceal peritoneal metastases: lessons learned from PRODIGE 7

The treatment for peritoneal metastases from appendiceal, colon and rectal cancer (MO1) has relied on cytoreductive surgery (CRS) to remove all visible evidence of disease plus a perioperative chemotherapy for the entire abdomen to eliminate microscopic residual disease. Using the results obtained from the PRODIGE 7 randomized controlled trial, methodological issues were discussed and possible improvements to the hyperthermic intraperitoneal chemotherapy (HIPEC) with oxaliplatin were sought. Possible methodological and pharmacologic flaws were identified. Several methodological flaws included the sample size, cross-over option, neoadjuvant chemotherapy use and timing of the peritoneal disease evaluation. The sample size issue raised the question of what the minimal clinically relevant benefit we want in future trials. Neoadjuvant FOLFOX may have induced acquired drug resistance to oxaliplatin. Several pharmacological issues were identified including limited 5-fluorouracil exposure as well as limited oxaliplatin peritoneal exposure time. Insufficient 5-fluorouracil accompanied the oxaliplatin as only a bolus dose was used and continuous 5-FU infusion has previously been an integral part of oxaliplatin treatment. Finally, only approximately one-half of the oxaliplatin entered body tissues or tumor. Three suggestions from the lessons learned from a critique of PRODIGE 7 were offered as adjustments to the HIPEC protocol. The Efficacy of HIPEC, a perioperative FOLFOX or a return to HIPEC with mitomycin C were described.

Cytoreductive surgery plus hyperthermic intraperitoneal chemotherapy versus cytoreductive surgery alone for colorectal peritoneal metastases (PRODIGE 7): a multicentre, randomised, open-label, phase 3 trial

BACKGROUND

The addition of hyperthermic intraperitoneal chemotherapy (HIPEC) to cytoreductive surgery has been associated with encouraging survival results in some patients with colorectal peritoneal metastases who were eligible for complete macroscopic resection. We aimed to assess the specific benefit of adding HIPEC to cytoreductive surgery compared with receiving cytoreductive surgery alone.

METHODS

We did a randomised, open-label, phase 3 trial at 17 cancer centres in France. Eligible patients were aged 18-70 years and had histologically proven colorectal cancer with peritoneal metastases, WHO performance status of 0 or 1, a Peritoneal Cancer Index of 25 or less, and were eligible to receive systemic chemotherapy for 6 months (ie, they had adequate organ function and life expectancy of at least 12 weeks). Patients in whom complete macroscopic resection or surgical resection with less than 1 mm residual tumour tissue was completed were randomly assigned (1:1) to cytoreductive surgery with or without oxaliplatin-based HIPEC. Randomisation was done centrally using minimisation, and stratified by centre, completeness of cytoreduction, number of previous systemic chemotherapy lines, and timing of protocol-mandated systemic chemotherapy. Oxaliplatin HIPEC was administered by the closed (360 mg/m²) or open (460 mg/m²) abdomen techniques, and systemic chemotherapy (400 mg/m² fluorouracil and 20 mg/m² folinic acid) was delivered intravenously 20 min before HIPEC. All individuals received systemic chemotherapy (of investigators' choosing) with or without targeted therapy before or after surgery, or both. The primary endpoint was overall survival, which was analysed in the intention-to-treat population. Safety was assessed in all patients who received surgery. This trial is registed with ClinicalTrials.gov, NCT00769405, and is now completed.

FINDINGS

Between Feb 11, 2008, and Jan 6, 2014, 265 patients were included and randomly assigned, 133 to the cytoreductive surgery plus HIPEC group and 132 to the cytoreductive surgery alone group. After median follow-up of 63·8 months (IQR 53·0-77·1), median overall survival was 41·7 months (95% CI 36·2-53·8) in the cytoreductive surgery plus HIPEC group and 41·2 months (35·1-49·7) in the cytoreductive surgery group (hazard ratio 1·00 [95·37% CI 0·63-1·58]; stratified log-rank p=0·99). At 30 days, two (2%) treatment-related deaths had occurred in each group.. Grade 3 or worse adverse events at 30 days were similar in frequency between groups (56 [42%] of 133 patients in the cytoreductive surgery plus HIPEC group vs 42 [32%] of 132 patients in the cytoreductive surgery group; p=0·083); however, at 60 days, grade 3 or worse adverse events were more common in the cytoreductive surgery plus HIPEC group (34 [26%] of 131 vs 20 [15%] of 130; p=0·035).

INTERPRETATION

Considering the absence of an overall survival benefit after adding HIPEC to cytoreductive surgery and more frequent postoperative late complications with this combination, our data suggest that cytoreductive surgery alone should be the cornerstone of therapeutic strategies with curative intent for colorectal peritoneal metastases.

FUNDING

Institut National du Cancer, Programme Hospitalier de Recherche Clinique du Cancer, Ligue Contre le Cancer.

Colorectal cancer cells from patients treated with FOLFOX or CAPOX are resistant to oxaliplatin

BACKGROUND

Numerous studies have suggested benefit for heated intraperitoneal chemotherapy (HIPEC) in the treatment of peritoneal metastases from colon cancer. However, the PRODIGE 7 trial that randomized 265 colon cancer patients to surgery plus HIPEC vs. surgery alone after neoadjuvant chemotherapy (NACT) did not confirm benefit. These data were published as an abstract and not as a peer-reviewed manuscript. One concern is that prior drug exposure may select for drug resistance and blunt HIPEC efficacy.

METHODS

A database query identified colon cancer specimens evaluated for chemotherapy sensitivity by ex-vivo analysis of programmed cell death (EVA/PCD), a primary culture platform that examines drug-induced cell death (apoptotic & non-apoptotic) by morphologic, metabolic and histologic endpoints.

RESULTS

Of 87 fresh colon cancer specimens, 54 (62%) were untreated and 33 (38%) had received prior folinic acid, 5-fluorouracil, oxaliplatin (FOLFOX) or capecitabine and oxaliplatin (CAPOX). In an apoptosis assay, the lethal concentration of 50% (LC50) in untreated patients was significantly lower than in patients treated by FOLFOX (p = 0.002). Then to approximate PRODIGE 7, treated patients were separated by having received oxaliplatin treatment less than or greater than 2 months before EVA/PCD analysis. The degree of resistance increasing significantly for patients who received treatment less than 2 months prior to EVA/PCD (p < 0.002). Activity for mitomycin and irinotecan was not significantly different for untreated vs. treated patients, but 5-FU was more resistant (P = 0.048).

CONCLUSIONS

The failure of PRODIGE 7 to improve survival with surgery plus HIPEC following NACT may reflect diminished oxaliplatin cytotoxicity in patients whose residual disease has been selected for oxaliplatin and 5-FU resistance.

Perioperative FOLFOX in management of peritoneal metastases of colorectal cancer. Case report of 2 patients

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Peritoneal metastases from colorectal cancer are lethal.

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Cytoreductive surgery plus perioperative chemotherapy is a treatment option.

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A perioperative FOLFOX regimen with intraperitoneal oxaliplatin was described.

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The pharmacokinetic studies suggested efficacy.

Introduction

Colorectal cancer can disseminate malignant cells to the peritoneal surfaces which over time progress to peritoneal metastases. Management of this type of metastatic disease has been approached using a combined treatment that consists of cytoreductive surgery and perioperative chemotherapy. To optimize these treatments a more effective chemotherapy that is used as planned part of the surgical procedure is required.

Presentation of cases

Pharmacologic studies to initiate a new perioperative chemotherapy treatment were modeled after the successful systemic treatments of metastatic colorectal cancer referred to as FOLFOX. A management plan that included all of the essential features of successful systemic chemotherapy was formulated. Pharmacokinetic studies of 5-fluorouracil given both intravenously and intraperitoneally and oxaliplatin given intraperitoneally were investigated.

Discussion

The compatibility of 5-fluorouracil and oxaliplatin was documented showing no degradation of either drug when they were mixed in-vitro over 24 h. The pharmacokinetic analysis of hyperthermic intraperitoneal chemotherapy (HIPEC) with oxaliplatin showed cytotoxic concentrations for 120 min. In order to maximize oxaliplatin’s effect, both intravenous bolus and continuous infusion 5-fluorouracil was combined with early postoperative intraperitoneal chemotherapy (EPIC). In total, 200 mg/m² of oxaliplatin was combined with a minimum of 1600 mg of 5-fluorouracil over the 24 -h treatment plan.

Conclusion

This perioperative FOLFOX treatment was completed in 2 patients and the clinical effectiveness as a result of this in-depth case reports was presented. Formal phase II studies, as a result of these pharmacokinetic and clinical investigations, have been initiated.

Wide variation in tissue, systemic, and drain fluid exposure after oxaliplatin-based HIPEC: results of the GUTOX study

Purpose

In this exploratory study, the effect of postprocedural flushing with crystalloids after oxaliplatin-based hyperthermic intraperitoneal chemotherapy (HIPEC) on platinum concentrations in peritoneal tissue, blood, and drain fluid was studied. Interpatient variability in oxaliplatin pharmacokinetics and the relation between platinum concentration in peritoneal fluid and platinum exposure in tissue and blood was explored.

Methods

Ten patients with peritoneal carcinomatosis of colorectal origin were treated with HIPEC including postprocedural flushing, followed by ten patients without flushing afterwards. Tissue, peritoneal fluid, blood, and drain fluid samples were collected for measurement of total and ultrafiltered platinum concentrations.

Results

Peritoneal tissue concentration and systemic ultrafiltered platinum exposure showed large inter individual variability, ranging from 65 to 1640 µg/g dry weight and 10.5 to 28.0 µg*h/ml, respectively. No effect of flushing was found on geometric mean platinum concentration in peritoneal tissue (348 vs. 356 µg/g dry weight), blood (14.8 vs. 18.1 µg*h/ml), or drain fluid (day 1: 7.6 vs. 7.7 µg/ml; day 2: 1.7 vs. 1.9 µg/ml). The platinum concentration in peritoneal fluid at the start of HIPEC differed twofold between patients and was positively correlated with systemic exposure (p = .04) and peak plasma concentration (p = .04).

Conclusion

In this exploratory study, no effect was found for postprocedural flushing on platinum concentrations in peritoneal tissue, blood, or drain fluid. BSA-based HIPEC procedure leads to large interpatient variability in platinum exposure in all compartments.

The study was registered at ClinicalTrials.gov on 7 December 2017 under registration number NCT03364907.

The PEritoneal SUrface CAlculator (PESUCA): A new tool to quantify the resected peritoneal surface area after cytoreductive surgery

BACKGROUND

The body surface area (BSA) is taken as a measure for the effective contact area for dosing in hyperthermic intraperitoneal chemotherapy (HIPEC). Currently, the pharmacokinetic effect of the reduced peritoneal surface area (PSA) after cytoreductive surgery (CRS) during HIPEC remains unclear. Here a proprietary software solution (PEritoneal SUrface CAlculator (PESUCA)) to quantify the resected PSA in patients with peritoneal surface malignancies (PSM) undergoing CRS and HIPEC is presented.

METHODS

The PESUCA tool was programmed as a desktop and online software solution. The applicability was evaluated in 36 patients. The programming-algorithm is briefly summarized as follows: (1) calculation of BSA, (2) correlation to PSA, (3) calculation of the relative proportion of 40 different anatomical regions to total PSA before CRS, (4) instantaneous input of each resected proportion in the 40 anatomical regions during CRS, and (5) determination of the resected and remaining PSA after CRS.

RESULTS

The proof of concept revealed a mean PSA of all patients before CRS of 18,741 ± 321 cm2 compared to 13,611 ± 485 cm2 after CRS (p<0.0001). Patients' supramesocolic and inframesocolic visceral and parietal peritoneal area before and after CRS procedure were quantitatively determined.

CONCLUSIONS

Here the first tool that enables detailed PSA quantification in patients with PSM undergoing CRS is presented. This makes the software a valuable contribution to ensue more accurate assessment and improved comparability of peritoneal disease extent. Furthermore, after external validation, PESUCA could be the basis for dose adjustment of intraperitoneal chemotherapy regimens based on the remaining PSA after CRS.

Peritoneal mesothelioma

Malignant peritoneal mesothelioma (MPM) is a rare and lethal disease of the peritoneal lining, with high variability in biologic aggressiveness. Morbidity and mortality of the disease are related to progressive locoregional effects within the abdominal cavity, such as distention, pain, early satiety, and decreased oral intake that can ultimately lead to bowel obstruction and cachexia. The standard of care for patients with resectable disease remains cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC), with potential survival outcomes greater than 5 years in appropriately selected patients. Patients with inoperable MPM can be offered systemic treatment, although the disease is usually refractory to standard chemotherapic regimens. Patients with MPM should be treated at high volume centers with strong consideration for inclusion in tumor registries and clinical trials. In 2020, research will continue to explore promising genetic and immunologic targets and focus on refinement of surgical methods to optimize CRS-HIPEC approaches.

Phase II randomized study on tissue distribution and pharmacokinetics of cisplatin according to different levels of intra-abdominal pressure (IAP) during HIPEC (NCT02949791)

AIMS

To evaluate the effects of high intra-abdominal pressure (IAP) during hyperthermic intraperitoneal chemotherapy (HIPEC) on cisplatin uptake by residual tumor and normal tissues, pharmacokinetics, and short-term surgical outcomes.

PATIENTS & METHODS

Patients with peritoneal metastasis from colorectal cancer or pseudomyxoma peritonei were randomized to closed-abdomen HIPEC with low-IAP or high-IAP, after complete cytoreduction. High-IAP was obtained increasing the volume of perfusate maintaining constant the cisplatin concentration (42 mg/L). We determined the Platinum concentration using an Inductive Coupled Plasma Mass Spectrometry System. Randomization was stratified according to tumor type. To consider the multiple sampling in the three tissues types of interest, we performed linear mixed models to assess the differences of cisplatin concentration between study arms. We also compared AUC perfusate/plasma ratios (Wilcoxon-Mann-Whitney) and perioperative severe complication rates (chi-square) between study arms.

RESULTS

38 cases were randomly assigned to IAP arms (n = 19 each). Median IAPs were 19 mmHg and 11 mmHg in the high and low arms, respectively. Cisplatin concentrations did not differ in the tumor residual tissues and in the muscular fascia [22.8 ng/mg (SD: 25.5) vs. 15.9 ng/mg (SD: 13.3), p = 0.181] and [50.3 ng/mg (SD: 40.1) vs. 42.0 ng/mg (SD: 38.3), p = 0.426, respectively], whereas in the mesenteric peritoneum it did [5.4 ng/mg (SD: 7.82) vs. 2.7 ng/mg (SD: 2.9), p = 0.048]. Pharmacokinetic advantage did not differ between the two arms. High-IAP did not increase perioperative severe complications rate (NCI-CTCAE.v3).

CONCLUSIONS

high-IAP HIPEC increases cisplatin distribution in the mesenteric peritoneum, is safe, and could be considered to obtain microscopic cytoreduction.