Prognostic value of specific KRAS mutations in patients with colorectal peritoneal metastases.

BACKGROUND: There is little evidence on KRAS mutational profiles in colorectal cancer (CRC) peritoneal metastases (PM). This study aims to determine the prevalence of specific KRAS mutations and their prognostic value in a homogeneous cohort of patients with isolated CRC PM treated with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. MATERIALS AND METHODS: Data were collected from 13 Italian centers, gathered in a collaborative group of the Italian Society of Surgical Oncology. KRAS mutation subtypes have been correlated with clinical and pathological characteristics and survival [overall survival (OS), local (peritoneal) disease-free survival (LDFS) and disease-free survival (DFS)]. RESULTS: KRAS mutations occurred in 172 patients (47.5%) out of the 362 analyzed. Two different prognostic groups of KRAS mutation subtypes were identified: KRASMUT1 (G12R, G13A, G13C, G13V, Q61H, K117N, A146V), median OS > 120 months and KRASMUT2 (G12A, G12C, G12D, G12S, G12V, G13D, A59E, A59V, A146T), OS: 31.2 months. KRASMUT2 mutations mainly occurred in the P-loop region (P < 0.001) with decreased guanosine triphosphate (GTP) hydrolysis activity (P < 0.001) and were more frequently related to size (P < 0.001) and polarity change (P < 0.001) of the substituted amino acid (AA). When KRASMUT1 and KRASMUT2 were combined with other known prognostic factors (peritoneal cancer index, completeness of cytoreduction score, grading, signet ring cell, N status) in multivariate analysis, KRASMUT1 showed a similar survival rate to KRASWT patients, whereas KRASMUT2 was independently associated with poorer prognosis (hazard ratios: OS 2.1, P < 0.001; DFS 1.9, P < 0.001; LDFS 2.5, P < 0.0001). CONCLUSIONS: In patients with CRC PM, different KRAS mutation subgroups can be determined according to specific codon substitution, with some mutations (KRASMUT1) that could have a similar prognosis to wild-type patients. These findings should be further investigated in larger series.

External multicentre validation of pseudomyxoma peritonei PSOGI-Ki67 classification.

BACKGROUND: Pseudomyxoma peritonei (PMP) is a rare malignant disease. Adding of the Ki67 proliferation index to the PSOGI PMP classification provided two different subcategories of the extensive HG-PMP group (HG-PMP ≤15% and HG-PMP >15%) with different survival in a previous unicentric study. This study aims to carry out an external and multicentre validation of this new proposed classification. METHOD: It was a prospective analysis of samples from a historical and international cohort of patients. A representative area with higher cellular density was used to determine the Ki67%. The Ki67 proliferation index (%) was determined in all the HG-PMP patients. A Cox proportional hazard models and multivariable COX models were used. The Kaplan-Meier method and the two-tailed log-rank test were used to analyse the effect of different PSOGI-Ki67 categories on OS and DFS. Its predictive accuracy was analysed using Harrel's C-index and the ROC curve. The calibration was performed using the calibration plots matching. RESULTS: After exclusions, 349 patients were available for analysis. The 5-years OS were 86% for LG-PMP, 59% for HG-PMP≤15, 38% for HG-PMP>15 and 42% for SRC-PMP (p = 0.0001). The 5-years DFS were 49% for LG-PMP, 35% for HG-PMP≤15, 16% for HG-PMP>15 and 18% SRC-PMP (p = 0.0001). The discrimination capability of PSOGI-Ki67 was validated. CONCLUSION: the PSOGI-Ki67 classification discriminates and predicts the OS and DFS in patients with PMP dividing the HG-PMP category into two well-defined sub-categories. The Ki67 proliferation index should be incorporated routinely in the pathology report for these patients.

Validation of a Nomogram to Predict Recurrence in Patients with Mucinous Neoplasms of the Appendix with Peritoneal Dissemination After Cytoreductive Surgery and HIPEC.

BACKGROUND: Survival of patients affected by mucinous appendiceal neoplasms with peritoneal dissemination (PD) is mainly related to histopathological features. However, prognostic stratification is still a concern, as the clinical course of the disease is often unpredictable. The aim of this study is to construct and externally validate a nomogram predicting disease-free survival (DFS) in mucinous appendiceal neoplasms with PD treated by cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). PATIENTS AND METHODS: Patients treated in two referral centers were included: Hospital General Universitario Gregorio Marañón, Madrid, Spain (derivation cohort) and Fondazione IRCCS Istituto Nazionale Tumori, Milan, Italy (validation cohort). Cox regression analysis identified factors associated with shorter DFS in the derivation cohort. The nomogram performance was externally evaluated in the validation cohort using concordance index and calibration plots. Histology was classified according to the Peritoneal Surface Oncology Group International (PSOGI). RESULTS: The derivation cohort included 95 patients, and the validation cohort 348. Five-year DFS rates were 51.5 and 62%, respectively. Cox regression analysis (derivation cohort) identified PSOGI histology of the peritoneal components, number of preoperative elevated tumor marker, and peritoneal disease extent, as assessed by peritoneal carcinomatosis index, to be predictors of DFS. The model's predictive capacity was higher than that of PSOGI classification alone, with respective concordance indexes of 0.702 ± 0.023 and 0.610 ± 0.018 (validation cohort). The nomogram approximated the perfect model in the calibration plots at 3- and 5-year DFS. CONCLUSIONS: An easy-to-use model that provides better prognostic stratification than histopathological features has been constructed. This nomogram may help clinicians in individualized survival predictions and informed clinical decision-making.

Preliminary results of a program for the implementation of laparoscopic colorectal surgery in an Italian comprehensive cancer center during the COVID-19 pandemic.

Despite operative benefit and oncological non-inferiority, videolaparoscopic (VLS) colorectal surgery is still relatively underutilized. This study analyzes the results of a program for the implementation of VLS colorectal surgery started in an Italian comprehensive cancer center shortly before COVID-19 outbreak. A prospective database was reviewed. The study period was divided in four phases: Phase-1 (Open surgery), Phase-2 (Discretional phase), Phase-3 (VLS implementation phase), and Phase-4 (VLS consolidation phase). Formal surgical and perioperative protocols were adopted from Phase-3. Postoperative complications were scored by the Clavien-Dindo classification. 414 surgical procedures were performed during Phase-1, 348 during Phase-2, 360 during Phase-3, and 325 during Phase-4. In the four phases, VLS primary colorectal resections increased from 11/214 (5.1%), to 55/163 (33.7%), 85/151 (57.0%), and 109/147 (74.1%), respectively. The difference was statistically significant (P < 0.001). All-type VLS procedures were 16 (3.5%), 61 (16.2%), 103 (27.0%), and 126 (38.6%) (P < 0.001). Conversions to open surgery of attempted laparoscopic colorectal resections were 17/278 in the overall series (6.1%), and 12/207 during Phase-3 and Phase-4 (4.3%). Severe (grades IIIb-to-V) postoperative complications of VLS colorectal resections were 9.1% in Phase-1, 12.7% in Phase-2, 12.8% in Phase-3, and 5.3% in Phase-4 (P = 0.677), with no significant differences with open resections in each of the four phases: 9.4% (P = 0.976), 11.1% (P = 0.799), 13.8% (P = 1.000), and 8.3% (P = 0.729). Despite the difficulties deriving from the COVID-19 outbreak, our experience suggests that volume of laparoscopic colorectal surgery can be significantly and safely increased in a specialized surgical unit by means of strict operative protocols.

The Delphi and GRADE methodology used in the PSOGI 2018 consensus statement on Pseudomyxoma Peritonei and Peritoneal Mesothelioma.

Pseudomyxoma Peritonei (PMP) and Peritoneal Mesothelioma (PM) are both rare peritoneal malignancies. Currently, affected patients may be treated with Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy offering long-term survival or even cure in selected patients. However, many issues regarding the optimal treatment strategy are currently under debate. To aid physicians involved in the treatment of these patients in clinical decision making, the PSOGI executive committee proposed to create a consensus statement on PMP and PM. This manuscript describes the methodology of the consensus process. The Delphi technique is a reliable method for attaining consensus on a topic that lacks scientific evidence through multiple voting rounds which feeds back responses to the participants in between rounds. The GRADE system provides a structured framework for presenting and grading the available evidence. Separate questionnaires were created for PMP and PM and sent during two voting rounds to 80 and 38 experts, respectively. A consensus threshold of 51.0% was chosen. After the second round, consensus was reached on 92.9%-100.0% of the questions. The results were presented and discussed in the plenary session at the PSOGI 2018 international meeting in Paris. A third round for the remaining issues is currently in progress. In conclusion, using the Delphi technique and GRADE methodology, consensus was reached in many issues regarding the treatment of PM and PMP amongst an international panel of experts. The main results will be published in the near future.

Appendiceal tumours and pseudomyxoma peritonei: Literature review with PSOGI/EURACAN clinical practice guidelines for diagnosis and treatment.

Pseudomyxoma Peritonei (PMP) is a rare peritoneal malignancy, most commonly originating from a perforated epithelial tumour of the appendix. Given its rarity, randomized controlled trials on treatment strategies are lacking, nor likely to be performed in the foreseeable future. However, many questions regarding the management of appendiceal tumours, especially when accompanied by PMP, remain unanswered. This consensus statement was initiated by members of the Peritoneal Surface Oncology Group International (PSOGI) Executive Committee as part of a global advisory role in the management of uncommon peritoneal malignancies. The manuscript concerns an overview and analysis of the literature on mucinous appendiceal tumours with, or without, PMP. Recommendations are provided based on three Delphi voting rounds with GRADE-based questions amongst a panel of 80 worldwide PMP experts.

Appendiceal tumours and pseudomyxoma peritonei: Literature review with PSOGI/EURACAN clinical practice guidelines for diagnosis and treatment

Pseudomyxoma Peritonei (PMP) is a rare peritoneal malignancy, most commonly originating from a perforated epithelial tumour of the appendix. Given its rarity, randomized controlled trials on treatment strategies are lacking, nor likely to be performed in the foreseeable future. However, many questions regarding the management of appendiceal tumours, especially when accompanied by PMP, remain unanswered. This consensus statement was initiated by members of the Peritoneal Surface Oncology Group International (PSOGI) Executive Committee as part of a global advisory role in the management of uncommon peritoneal malignancies. The manuscript concerns an overview and analysis of the literature on mucinous appendiceal tumours with, or without, PMP. Recommendations are provided based on three Delphi voting rounds with GRADE-based questions amongst a panel of 80 worldwide PMP experts.

The Delphi and GRADE methodology used in the PSOGI 2018 consensus statement on Pseudomyxoma Peritonei and Peritoneal Mesothelioma

Pseudomyxoma Peritonei (PMP) and Peritoneal Mesothelioma (PM) are both rare peritoneal malignancies. Currently, affected patients may be treated with Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy offering long-term survival or even cure in selected patients. However, many issues regarding the optimal treatment strategy are currently under debate. To aid physicians involved in the treatment of these patients in clinical decision making, the PSOGI executive committee proposed to create a consensus statement on PMP and PM. This manuscript describes the methodology of the consensus process. The Delphi technique is a reliable method for attaining consensus on a topic that lacks scientific evidence through multiple voting rounds which feeds back responses to the participants in between rounds. The GRADE system provides a structured framework for presenting and grading the available evidence. Separate questionnaires were created for PMP and PM and sent during two voting rounds to 80 and 38 experts, respectively. A consensus threshold of 51.0% was chosen. After the second round, consensus was reached on 92.9%-100.0% of the questions. The results were presented and discussed in the plenary session at the PSOGI 2018 international meeting in Paris. A third round for the remaining issues is currently in progress. In conclusion, using the Delphi technique and GRADE methodology, consensus was reached in many issues regarding the treatment of PM and PMP amongst an international panel of experts. The main results will be published in the near future.

Cytoreductive surgery and HIPEC improve survival compared to palliative chemotherapy for biliary carcinoma with peritoneal metastasis: A multi-institutional cohort from PSOGI and BIG RENAPE groups.

BACKGROUND: Peritoneal metastasis from biliary carcinoma (PMC) is associated with poor prognosis when treated with chemotherapy. OBJECTIVE: To evaluate the impact on survival of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC), and compare with conventional palliative chemotherapy for patients with PMC. MATERIAL AND METHODS: A prospective multicenter international database was retrospectively searched to identify all patients with PMC treated with a potentially curative CRS/HIPEC (CRS/HIPEC group). The overall survival (OS) was compared to patients with PMC treated with palliative chemotherapy (systemic chemotherapy group). Survival was analyzed using Kaplan-Meier method and compared with Log-Rank test. RESULTS: Between 1995 and 2015, 34 patients were included in the surgical group, and compared to 21 in the systemic chemotherapy group. In the surgical group, median peritoneal cancer index was 9 (range 3-26), macroscopically complete resection was obtained for 25 patients (73%). There was more gallbladder localization in the surgical group compared to the chemotherapy group (35% vs. 18%, p = 0.001). Median OS was 21.4 and 9.3 months for surgical and chemotherapy group, respectively (p=0.007). Three-year overall survival was 30% and 10% for surgical and chemotherapy group, respectively. CONCLUSION: Treatment with CRS and HIPEC for biliary carcinoma with peritoneal metastasis is feasible and may provide survival benefit when compared to palliative chemotherapy.

The current practice of cytoreductive surgery and HIPEC for colorectal peritoneal metastases: Results of a worldwide web-based survey of the Peritoneal Surface Oncology Group International (PSOGI).

BACKGROUND: At present, selected patients with resectable colorectal peritoneal metastases (CRC-PM) are increasingly treated with a combination therapy of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). The aim of this study was to investigate the current worldwide practice. METHODS: HIPEC experts from 19 countries were invited through the Peritoneal Surface Oncology Group International (PSOGI) to complete an online survey concerning their personal expertise and current hospital and countrywide practice. RESULTS: It is estimated that currently more than 3800 patients with CRC-PM (synchronous and metachronous) are annually treated with CRS and HIPEC in 430 centers. Integration of CRS and HIPEC in national guidelines varies, resulting in large treatment disparities between countries. Amongst the experts, there was general agreement on issues related to indication, surgical technique and follow up but less on systemic chemotherapy or proactive strategies. CONCLUSION: This international survey demonstrates that CRS and HIPEC is now performed on a large scale for CRC-PM patients. Variation in treatment may result in heterogeneity in surgical and oncological outcomes, emphasising the necessity to reach consensus on several issues of this comprehensive procedure. Future initiatives directed at achieving an international consensus statement are needed.

Toward the molecular dissection of peritoneal pseudomyxoma.

BACKGROUND: Outcome of pseudomyxoma peritonei (PMP) after cytoreductive surgery (CRS) and hypertermic intraperitoneal chemotherapy (HIPEC) is heterogeneous even after adjusting for clinico-pathological prognostic variables. The identification of additional prognostic or even predictive biomarkers is an unmet clinical need. PATIENTS AND METHODS: Forty patients with mucinous appendiceal tumors and PMP were clinically eligible and had evaluable tumor samples obtained after CRS and HIPEC. We carried out next-generations sequencing (NGS) of 50 gene's hotspot regions contained in the Hotspot Cancer Panel v2 using the Ion Torrent Personal Genome Machine platform (Life Technologies). RESULTS: KRAS and GNAS mutations were found in 72% and 52%, and their allelic frequency was below 10% in 55% and 43% of samples, respectively. KRAS and GNAS mutations were associated with worse progression-free survival (PFS) at univariate analysis (P = 0.006 and 0.011, respectively). At multivariate analysis, only KRAS mutations were independently associated with PFS (P = 0.012); GNAS mutations were not-being significantly associated with other poor prognostic features such as incomplete cytoreduction or KRAS mutations. Validation of results was carried out in an independent bi-institutional cohort of 25 patients and the prognostic effect of KRAS mutations was again confirmed in the multivariate model (P = 0.029). NGS approach allowed the discovery of other potentially druggable mutations such as those in PI3K, AKT, LKB1, FGFR3 and PDGFRA. CONCLUSIONS: Given the homogeneity of this series and the sensitivity of NGS in this low-cellularity tumor, we demonstrated for the first time a poor prognostic role of KRAS mutations.

A comprehensive treatment for peritoneal metastases from gastric cancer with curative intent.

Recently, Peritoneal Surface Oncology Group International (PSOGI) developed a novel comprehensive treatment consisting of cytoreductive surgery (CRS) and perioperative chemotherapy (POC) for the treatment of peritoneal metastases (PM) from gastric cancer with curative intent. This article reviews the results of this treatment and verifies its indication. In this strategy, peritoneal cancer index (PCI) is determined by laparoscopy, and a peritoneal port is placed. Neoadjuvant bidirectional intraperitoneal/systemic chemotherapy (NIPS) is performed for 3 cycles, and then laparotomy is performed. Cytoreductive surgery with peritonectomy procedures and hyperthermic intraperitoneal chemoperfusion (HIPEC) are performed. Multivariate analyses showed that completeness of cytoreduction, pathologic response to NIPS and PCI level and cytologic status after NIPS, as independent prognostic factors. PCI less than cut-off level after NIPS, negative cytology after NIPS, and positive response to NIPS were identified as the indications for comprehensive treatment. Patients who hold these criteria should be considered as the candidates for CRS and HIPEC.

The role of baseline inflammatory-based scores and serum tumor markers to risk stratify pseudomyxoma peritonei patients treated with cytoreduction (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).

AIMS: Inflammation-based scores such as neutrophil-lymphocyte ratio (NLR) and Onodera nutritional index (ONI) have been identified as new prognosticators in several tumors. We conducted a prognostic analysis of these markers and performed a risk stratification of PMP patients submitted to cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). METHODS: 226 patients from two peritoneal surface malignancies centers participated in this study. Cox proportional modeling was used to select predictors of overall survival (OS) among baseline inflammation-based scores, serum tumor markers, clinical and surgical variables. Risk stratification was done using conditional inference tree model. RESULTS: One hundred eighty-two cases had diffuse peritoneal adenomucinosis subtype. Fifty-four cases had received previous systemic chemotherapy. The means of ONI and NLR were 51.4 (SD = 9.8) and 3.2 (SD = 2.3), respectively. Two hundred ten cases were optimally cytoreduced. Cox analysis identified completeness of cytoreduction, histological subtype, previous systemic chemotherapy, NLR, and CA 19-9 as independent prognosticators. Conditional inference tree method identified two poor prognostic subsets: NLR ≤2.7 and CA 19-9>336 (5yr-OS = 15%) and NLR >2.7 and ONI ≤42 (5yr-OS = 30%). CONCLUSIONS: NLR, ONI, and CA 19-9 are new prognosticators that contributed to improve prediction of OS in PMP patients treated by CRS and HIPEC. These markers allowed a risk stratification that could optimize therapeutic management of PMP patients.

Peritoneal metastases: challenges for the surgeon.

Peritoneal surface malignancies (PSM) include peritoneal metastases from gastrointestinal and gynecological tumor and rare primary peritoneal malignancies. PSM have been historically considered as end-stage metastatic conditions only amenable to palliative options. Only in recent years, better knowledge of their natural history and pattern of disease-progression has evolved into the concept that PSM represent a local-regional disease stage. A novel treatment approach aiming at definitive disease eradication combines aggressive cytoreductive surgery (CRS) and perioperative local-regional chemotherapy, either in the form of hyperthermic intraperitoneal chemotherapy (HIPEC), or normothermic early postoperative chemotherapy. Such a combined treatment approach has reportedly resulted in a survival improvement over historical controls, and it is gaining an increasing acceptance as standard of care for selected patients with PSM. This article reviews the most recent literature data on the surgical and comprehensive management of PSM. Epidemiology and natural history of the different disease entities are briefly discussed. Cytoreductive surgical procedures and intraperitoneal chemotherapy administration techniques are described, focusing on the technical variants adopted in our institution. Indications for combined treatment, and outcomes following CRS/HIPEC, are addressed, including peritoneal metastases from appendiceal tumors (pseudomyxoma peritonei), colorectal cancer, gastric cancer, epithelial ovarian cancer, and rare primary peritoneum based neoplasms, such as diffuse malignant peritoneal mesothelioma, and primary peritoneal (extra-ovarian) serous papillary carcinoma.

Multicentre study of the learning curve and surgical performance of cytoreductive surgery with intraperitoneal chemotherapy for pseudomyxoma peritonei.

BACKGROUND: The learning curves for cytoreductive surgery with intraperitoneal chemotherapy for treatment of pseudomyxoma peritonei (PMP) were explored between international centres/surgeons to identify institutional or other factors that might affect performance. METHODS: Data from patients with PMP treated with the combined procedure across 33 international centres between 1993 and 2012 were analysed retrospectively. A risk-adjusted sequential probability ratio test was conducted after defining the target outcome as early oncological failure (disease progression within 2 years of treatment), an acceptable risk for the target outcome (odds ratio) of 2, and type I/II error rates of 5 per cent. The risk prediction model was elaborated and patients were evaluated sequentially for each centre/surgeon. The learning curve was considered to be overcome and proficiency achieved when the odds ratio for early oncological failure became smaller than 2. RESULTS: Rates of optimal cytoreduction, severe postoperative morbidity and early oncological failure were 84·4, 25·7 and 29·0 per cent respectively. The median annual centre volume was 17 (range 6-66) peritoneal malignancies. Only eight of the 33 centres and six of 47 surgeons achieved proficiency after a median of 100 (range 78-284) and 96 (86-284) procedures respectively. The most important institutional factor affecting surgical performance was centre volume. CONCLUSION: The learning curve is extremely long, so centralization and/or networking of centres is necessary to assure quality of services. One centre for every 10-15 million inhabitants would be ideal.

Postoperative complications after cytoreductive surgery and hyperthermic intraperitoneal chemotherapy affect long-term outcome of patients with peritoneal metastases from colorectal cancer: a two-center study of 101 patients.

BACKGROUND: Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy is an effective but potentially morbid treatment for colorectal cancer peritoneal metastases. The impact of treatment-related morbidity on long-term survival has been reported in various malignancies, but it has never been assessed in this clinical setting. OBJECTIVE: The aim of this study was to assess the impact of major postoperative complications on oncological outcomes after cytoreduction and hyperthermic intraperitoneal chemotherapy for colorectal peritoneal metastases. DESIGN: Two prospective databases were reviewed. Major complications were defined as grade 3 to 5 according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 3.0. The extent of peritoneal involvement was scored by the use of the Peritoneal Cancer Index. SETTINGS: This study was conducted in 2 high-volume peritoneal malignancy management centers. PATIENTS: One hundred one consecutive patients with peritoneal metastases potentially amenable to macroscopically complete cytoreduction were selected. INTERVENTIONS: Peritonectomy procedures and multivisceral resections were used to remove all macroscopic tumor, and mitomycin-C plus cisplatin-based hyperthermic intraperitoneal chemotherapy was used to control microscopic residual disease. MAIN OUTCOME MEASURES: The primary outcomes measured were overall and disease-specific survival. RESULTS: Mortality and major morbidity were 3.0%, and 23.8%. Median follow-up was 44.9 months (95% CI, 24.1-65.7). Five-year disease-specific survival was 14.3% for patients who experienced major complications and 52.3% for those who did not (p = 0.001). Five-year overall survival was 11.7% for patients who experienced major complications, and 58.8% for those who did not (p = 0.003). At multivariate analysis, major morbidity correlated to both worse overall and disease-specific survival, along with a Peritoneal Cancer Index >19, and suboptimal cytoreduction. Poor performance status correlated only to worse disease-specific survival, and liver metastases correlated to worse overall survival. Longer operative time (OR, 4.1; 95% CI, 1.3-12.6; p = 0.01) and Peritoneal Cancer Index >19 (OR, 2.6; 95% CI, 1.1-6.0; p = 0.02) were independent risk factors for major morbidity. LIMITATIONS: This study is limited by its observational design. CONCLUSIONS: The prevention of major complications, by refining surgical technique and patient selection, is crucial because it affects oncologic outcome.

Secondary cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for recurrent epithelial ovarian cancer: a multi-institutional study.

OBJECTIVE: To assess the efficacy and morbidity and mortality of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) in recurrent epithelial ovarian cancer (EOC). DESIGN: A retrospective study conducted using information extracted from a multi-institutional prospective database on peritoneal surface malignancies (PSMs). Setting Four Italian centres specializing in locoregional treatment of PSM. POPULATION: Patients with recurrent EOC. METHODS: Fifty-six patients underwent 57 combined procedures. CRS was performed using peritonectomy procedures and HIPEC using the closed-abdomen technique with cisplatin and doxorubicin or cisplatin and mitomycin-C. MAIN OUTCOME MEASURES: Overall survival (OS), progression-free survival (PFS), morbidity and mortality rates. RESULTS: The median age of the patients was 55.2 years (range 30-75 years). The median peritoneal cancer index was 15.2 (range 4-30). Forty-seven patients had microscopic residual disease (completeness of cytoreduction, CC-0), seven had residual disease ≤2.5 mm (CC-1) and one had residual disease >2.5 mm (CC>2). Major complications occurred in 15 patients (26.3%), and procedure-related mortality occurred in three patients (5.3%). The median follow-up time was 23.1 months. The median OS and PFS were 25.7 (95% CI 20.3-31.0) and 10.8 (95% CI 5.4-16.2) months, respectively. The 5-year OS and PFS were 23% and 7%, respectively. Independent prognostic factors affecting OS according to the multivariate analysis were Eastern Cooperative Oncology Group performance status, preoperative serum albumin, and completeness of cytoreduction. CONCLUSIONS: Patients with recurrent EOC treated with CRS and HIPEC showed promising results in terms of outcome. The combined treatment strategy could benefit subsets of patients wider than that defined for conventional secondary debulking surgery without HIPEC. These data warrant further evaluation in randomised clinical trials.