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Background and Aim: Two-stage cytoreductive surgery (CRS) has been proposed as an alternative to one-stage surgery in patients who have 'extensive' pseudomyxoma peritonei (PMP) and/or are unfit for very extensive surgery, to reduce morbidity. We review current evidence on two-stage CRS focusing on patient selection, interval between procedures, extent of surgery, use of HIPEC, perioperative and oncological outcomes., Methods: This is a narrative review. A literature search on PubMed and Embase was performed using keywords- 'Two-stage cytoreductive surgery', 'pseudomyxoma peritonei', 'high-volume PMP', 'huge PMP', 'cytoreductive surgery', 'HIPEC', 'staged surgery' and 'extensive pseudomyxoma peritonei'., Results: Five studies reported outcomes in a total of 114 patients. The indications for two-stage CRS were: in two studies, patients undergoing an incomplete cytoreduction due to undue surgical risk were reevaluated for a second surgery during routine surveillance; severe comorbidities in one; extensive disease with PCI>28 in another and in one, only HIPEC was performed as a second procedure due to intraoperative hemodynamic instability (the two-stage procedure was performed in interest of patient's safety). Major morbidity ranged from 0 to 37.5 % (first-stage) and 25%-38.9 % (second-stage). Short term follow-up demonstrated equivalent short-term oncological outcomes compared to historical data. Long term follow-up and quality-of-life data were not available., Conclusions: The published studies showed different interpretations and applications of the two-stage CRS concept. The reported morbidity was similar to that after single-stage CRS for extensive PMP. Though short-term survival outcomes are acceptable, long-term follow-up is needed. Planned two-stage CRS should currently be reserved for highly selected clinical situations., Competing Interests: Declaration of competing interest The authors have no disclosures. The authors have no conflicts of interest., (Copyright © 2024 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Objective: The TORPEDO (CTRI/2018/12/016789) is the single-arm, prospective, interventional study evaluating the role of a total parietal peritonectomy (TPP) in patients undergoing interval cytoreductive surgery (iCRS). In this manuscript, we report the perioperative outcomes and platinum resistant recurrence (PRR) in 218 patients enrolled in the study., Methods: A TPP was performed in all patients undergoing iCRS irrespective of the residual disease extent. hyperthermic intraperitoneal chemotherapy (HIPEC) was performed as per the clinician's discretion with 75 mg/m² of cisplatin. Maintenance therapy was also used at the discretion of the treating clinicians., Results: From 9th December 2018 to 31st July 2022 (recruitment complete), 218 patients were enrolled at 4 medical centers in India. The median surgical peritoneal cancer index was 14 and a complete gross resection was achieved in 95.8%. HIPEC was performed in 130 (59.6%) patients. The 90-day major morbidity was 17.4% and 2.7% patients died within 90 days of surgery. Adjuvant chemotherapy was delayed beyond 6 weeks in 7.3%. At a median follow-up of 19 months (95% confidence interval [CI]=15.9-35 months), 101 (46.3%) recurrences and 19 (8.7%) deaths had occurred. The median progression-free survival was 22 months (95% CI=17-35 months) and the median overall survival (OS) not reached. Platinum resistant recurrence was observed in 6.4%. The projected 3-year OS was 81.5% and in 80 patients treated before may 2020, it was 77.5%., Conclusion: The morbidity and mortality of TPP with or without HIPEC performed during iCRS is acceptable. The incidence was of PRR is low. Early survival results are encouraging and warrant conduction of a randomized controlled trial comparing TPP with conventional surgery., Competing Interests: No potential conflict of interest relevant to this article was reported., (© 2024. Asian Society of Gynecologic Oncology, Korean Society of Gynecologic Oncology, and Japan Society of Gynecologic Oncology.)

Objective: To investigate the benefit of cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) for the treatment of endometrial peritoneal carcinomatosis compared to CRS alone., Methods: We conducted a retrospective multicentre study of patients from experienced centres in treating peritoneal malignancies from 2002 to 2015. Patients who underwent surgery for peritoneal evolution of endometrial cancer (EC) were included. Two groups of 30 women were matched and compared: "CRS + HIPEC" which used HIPEC after CRS, and "CRS only" which did not use HIPEC. We analysed clinical, pathologic and treatment data for patients with peritoneal metastases from EC. The outcome measures were morbidity, overall survival (OS), and progression-free survival (PFS)., Results: In "CRS plus HIPEC" group, 96.7% of women were treated for recurrence, while in "CRS only" 83.3 were treated for primary disease. There was no significant difference between Peritoneal Carcinomatosis Index at laparotomy or Completeness of Cytoreduction score. Grade III and IV complications rates did not significantly differ between "CRS plus HIPEC" group and "CRS only" group (20.7% vs 20.7%, p = 0.739). Survival analysis showed no statistical difference between both groups. Median OS time was 19.2 months in "CRS plus HIPEC" group and 29.7 months in "CRS only" group (p = 0.606). Median PFS survival time was 10.7 months in "CRS plus HIPEC" group and 13.1 months in "CRS only" group (p = 0.511)., Conclusion: The use of HIPEC combined to CRS did not have any significance as regard the DFS and OS over CRS alone in patients with primary or recurrent peritoneal metastasis of endometrial cancer., (© 2021. The Author(s).)

Background: The reported incidence of platinum resistant recurrence (PRR) (recurrence within 6 months of the last dose of platinum therapy) after interval debulking/cytoreductive surgery (CRS) is high compared to that after primary CRS. The goal was to study PRR following a total parietal peritonectomy (TPP), that addresses occult disease more completely., Methods: This is a prospective multi-center study (CTRI/2018/08/015350). A TPP was performed during interval CRS following a fixed surgical protocol. Patients with a follow-up of 6 months(M) or more were included in this analysis. The incidence and patterns of PRR and factors affecting recurrence were analyzed., Results: From July 2018 to October 2019, 70 patients with serous carcinoma were included. The median surgical PCI was 15 [range 5-37]. A CC-0 resection was obtained in 55 (78.5%); CC-1 in 10 (14.2%). Occult residual disease was seen in 40%. At a median follow-up of 13 months, 17 (24.2%) had developed recurrence/progression. PRR was seen in 5 (7.1%) patients. The sites of progression (>1 in 2 patients) were pleura (n = 1), visceral peritoneum (n = 2), retroperitoneal nodes (n = 2), mediastinal nodes (n = 1) and small bowel mesentery (n = 2). Overall, though the most common site of recurrence was the visceral peritoneum (N = 9), seven (>40%) patients did not develop recurrence in the visceral peritoneum. Patients with high PCI and grade 3-4 complications had a higher probability of developing recurrence., Conclusions: TPP performed during interval CRS resulted in a very low incidence of PRR. These findings need confirmation in a larger series. The benefit of TPP over conventional surgery should be evaluated in a randomized trial., Competing Interests: Declaration of competing interest, (Copyright © 2021 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Introduction: Despite 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 Analysis: There 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 Dissemination: The study protocol has been approved by the Zydus Hospital ethics committee (27 July, 2020) and Lyon-Sud ethics committee (A15-128)., Trial Registration Number: CTRI/2020/09/027709; Pre-results., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Patients undergoing cytoreductive surgery for colorectal peritoneal metastases who have a pathologic complete response (pCR) to neoadjuvant chemotherapy experience a significantly longer survival than those with residual disease. This response is known only after surgery. This study aimed to examine clinical and radiologic predictors of a pCR., Methods: From July 2018 to December 2019, the study prospectively enrolled 120 patients. The clinical and radiologic findings were compared between patients with and without a pCR. A protocol for pathologic evaluation was followed., Results: A pCR was observed in 34 patients (28.3%). Receiver operating characteristic (ROC) curves showed that patients with a surgical Peritoneal Cancer Index (sPCI) of 3 or lower had an 80% probability of experiencing a pCR, and that patients with a radiologic PCI (rPCI) of 2 or lower had a 70% probability of experiencing a pCR. A pCR was correctly predicted for 47% of the patients by imaging and for 44.4% of the patients by surgical evaluation. The site of primary tumor, the timing of peritoneal metastasis (PM), histology, tumor marker positivity, and mutations in known poor prognostic genes (KRAS) did not differ between the patients with and those without pCR. The primary tumor showed residual disease in 23.5% and regional nodes in 26.4% of the patients with pCR., Conclusions: The rPCI and sPCI concurred with a pCR in less than 50% of the patients. The patients with a lower PCI had greater concordance. An sPCI of 3 or lower was predictive of a pCR in 80% of the patients. The impact of KRAS mutations on pCR should be evaluated in a larger series. The predictors of pCR and response to systemic chemotherapy should be incorporated in prognostic scores used to select patients for surgery.

Objective: The aim of this study was to evaluate the patterns of recurrence and factors affecting the same after interval cytoreductive surgery and hyperthermic intraperitoneal chemotherapy in primary stage IIIC and IV A epithelial ovarian cancer., Methods: In this retrospective multicentric study, all patients with FIGO stages III-C and IV-A epithelial ovarian carcinoma were treated with CRS and HIPEC after receiving neoadjuvant chemotherapy. Relevant clinical and demographic data were captured. Multivariable logistic regression was performed to evaluate the factors affecting recurrence after CRS and HIPEC., Results: From January 2017 to Jan 2020, 97, consecutive patients of Stage IIIC/IVA epithelial ovarian cancer underwent interval cytoreductive surgery and HIPEC after receiving neoadjuvant chemotherapy. The median duration of follow up duration was 20 months [1-36months]. 21/97 (21.6%) patients presented with disease recurrence. Visceral recurrences involving the lungs, liver and brain were seen in 8/21 (38%) of cases and comprised the commonest sites. On multivariable analysis, nodal involvement (p = 0.05), selective peritonectomy (p = 0.001) and leaving behind residual disease <0.25 mm (CC1) (p = 0.01) was associated with increased risk of disease recurrence. Extent of peritonectomy (OS,p = 0.56, PFS p = 0.047, Log Rank test) and nodal positivity (OS, p = 0.13,PFS,p = 0.057, Log Rank test) were found to impact progression free survival but had no impact on overall survival., Conclusion: There is a higher incidence of systemic recurrences in patients with Stage IIIC/IVA epithelial ovarian carcinoma after CRS and HIPEC. Extent of peritonectomy and nodal clearance impacts patterns of recurrence and progression free survival., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2021 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Background: A surgical peritoneal cancer index of >20 is often used to exclude patients from cytoreductive surgery for colorectal peritoneal metastases. The pathologic peritoneal cancer index in these patients may be <20., Objective: The purpose of this study was to compare the pathologic and surgical findings and to look at potential pathologic prognostic factors., Design: This is a prospective observational study including patients undergoing cytoreductive surgery., Settings: The study was carried out at 3 peritoneal surface malignancy centers, 1 in France and 2 in India., Patients: One-hundred patients were included from July 1, 2018, to June 30, 2019., Main Outcome Measures: The pathologic peritoneal cancer index, peritoneal disease distribution, pathologic response to chemotherapy, factors affecting them and their relation with surgical findings, and potential prognostic value were explored., Results: Ninety percent had colonic primaries. Fifty-one percent had left-sided tumors. The median surgical peritoneal cancer index was 4 (range, 0-35). Upper regions were involved in 32% and small bowel regions in 26%, and their involvement increased with a higher peritoneal cancer index (p < 0.001). The median pathologic peritoneal cancer index was 2 (range, 0-27) and was less than the surgical peritoneal cancer index in 57%. A pathologic complete response was obtained in 25%. Patients with pathologic complete response received more antiepidermal growth factor receptor therapy (p = 0.008); more leucovorin, 5-fluorouracil, and oxaliplatin; and folinic acid, fluorouracilirin, irinotecan hydrochloride, and oxaliplatin (p < 0.001). In 7 patients with a surgical peritoneal cancer index of >20, pathologic peritoneal cancer index was <20 in 4 patients. Disease in the primary tumor/anastomotic site was found in ≈80%., Limitations: Survival outcomes are not available., Conclusions: Surgical peritoneal cancer index of >20 should not be the sole factor to exclude patients from surgery, especially in responders to systemic therapies. The pathologic peritoneal cancer index, pathologic response to systemic chemotherapy, and disease distribution in the peritoneal cavity should be meticulously documented. Correlation with survival will define their future prognostic value. The primary anastomotic site is a common site for peritoneal disease and should be carefully evaluated in all patients. See Video Abstract at http://links.lww.com/DCR/B490. IMPLICACIONES DE LOS HALLAZGOS PATOLÓGICOS EN MUESTRAS DE CIRUGÍA CITORREDUCTORA EN EL TRATAMIENTO DE METÁSTASIS PERITONEALES COLORRECTALES: RESULTADOS DE UN ESTUDIO PROSPECTIVO MULTICÉNTRICO: Una ICP quirúrgica de >20 se utiliza a menudo para excluir a los pacientes de la cirugía citorreductora por metástasis peritoneales colorrectales. La PCI patológica en estos pacientes puede ser <20.Comparar los hallazgos patológicos y quirúrgicos y observar los posibles factores pronósticos patológicos.Se trata de un estudio observacional prospectivo que incluye a pacientes sometidos a cirugía citorreductora.El estudio se llevó a cabo en tres centros de malignidad de la superficie peritoneal, 1 en Francia y 2 en India.Se incluyeron 100 pacientes desde el 1 de julio de 2018 al 30 de junio de 2019.No hubo intervención terapéutica.Se exploró la ICP patológica, la distribución de la enfermedad peritoneal, la respuesta patológica a la quimioterapia, los factores que la afectan y su relación con los hallazgos quirúrgicos y el valor pronóstico potencial.El noventa por ciento tenía lesiones primarias colónicas. El 51% tenía tumores del lado izquierdo. La mediana de la ICP quirúrgica 4 [0-35]. Las regiones superiores estuvieron involucradas en el 32% y las regiones del intestino delgado en un 26% y su participación aumentó con una ICP más alta (p <0,001). La mediana de la ICP patológica fue 2 [0-27] y fue menor que la ICP quirúrgica en el 57%. Se obtuvo respuesta patológica completa en el 25%. Los pacientes con respuesta patológica completa recibieron más terapia anti-EGFR (p = 0,008) y más FOLFOX y FOLFIRINOX (p <0,001). En 7 pacientes con una ICP quirúrgica de> 20, la ICP patológica fue menor de 20 en 4 pacientes. Se encontró enfermedad en el tumor primario/anastomósis en casi el 80%.Los resultados de supervivencia no están disponibles.La ICP quirúrgica de> 20 no debería ser el único factor para excluir a los pacientes de la cirugía, especialmente en los que responden a las terapias sistémicas. La PCI patológica, la respuesta patológica a la quimioterapia sistémica y la distribución de la enfermedad en la cavidad peritoneal deben documentarse meticulosamente. La correlación con la supervivencia definirá su valor pronóstico futuro. El sitio anastomótico primario es un sitio común de enfermedad peritoneal y debe evaluarse cuidadosamente en todos los pacientes. Consulte Video Resumen en http://links.lww.com/DCR/Bxxx. (Traducción-Dr. Gonzalo Hagerman).

Background: Total parietal peritonectomy (TPP) removes areas of "normal-appearing" parietal peritoneum bearing microscopic residual disease and has the potential to improve survival of patients undergoing interval cytoreductive surgery (CRS) for advanced serous epithelial ovarian cancer. This report presents the morbidity outcomes for the first 50 patients enrolled in TORPEDO (CTRI/2018/12/016789), a prospective study., Methods: All the patients underwent a TPP during interval CRS. A surgical protocol that includes a description of the boundaries for each of the five peritonectomies was followed. The common toxicology criteria for adverse events (CTCAE) classification was used to record 90-day morbidity and mortality., Results: The median Peritoneal Cancer Index (PCI) for 50 patients was 15 (range, 5-37). A complete cytoreduction (CC-0 resection) was obtained in 80%, a CC-1 resection in 16%. A bowel resection was performed in 70% of the patients. Grade 3 or 4 complications were seen in 11 patients (22%), and one patient died within 90 days after surgery due to intraperitoneal hemorrhage. The most common complications were postoperative fluid collection requiring aspiration (n = 5), intraperitoneal hemorrhage (n = 2), abdominal wound dehiscence (n = 2), pseudo-obstruction (n = 1), urinary sepsis (n = 2), and ileostomy-related complications (n = 2). No bowel fistulas or anastomotic leaks occurred. Microscopic disease in 'normal appearing' peritoneum adjacent to tumor nodules was observed in 46% of the patients, and in regions given a lesion score of 0 in 34%. The parietal peritoneal regions (0-8) had a higher incidence of residual disease (p < 0.001) and occult disease (p < 0.001)., Conclusions: During interval CRS, TPP can be performed with acceptable morbidity and mortality. The pathologic findings further support this therapeutic rationale. Survival outcomes should determine the future role of such a procedure in routine clinical practice.

Objectives: To compare clinical outcomes following total and selective peritonectomy performed during interval cytoreductive surgery (CRS) for stage IIIC/IVA serous epithelial ovarian cancer., Methods: In this retrospective study, extent of peritonectomy was classified as total parietal peritonectomy (TPP) which comprised of removal of the entire parietal peritoneum and the greater and lesser omenta or selective parietal peritonectomy (SPP) that included 1/>1 of parietal peritonectomies performed to resect sites of residual disease. A comparison of patient and disease characteristics, morbidity, mortality and survival outcomes between the two groups was made., Results: From January 2013 to December 2017, 79 patients underwent CRS (TPP-30, SPP-49) with or without intraperitoneal chemotherapy (IPC). The median PCI was 14 for TPP and 8 for SPP. The 90-day grade 3-4 morbidity (23.3% for TPP, 14.2% for SPP, p = 0.58) the 90-day mortality was similar (p = 0.58). The median disease free survival (DFS) was 37 months for SPP and 33 months for TPP (p = 0.47) and median overall survival (OS) not reached for both. The 3-year OS was 95% for TPP and 70.8% for SPP (p = 0.06). The only independent predictor of OS was grade 3-4 morbidity (p = 0.01) and not TPP (p = 0.09). Microscopic residual disease was seen in 23.3% with normal looking peritoneum in TPP group., Conclusions: TPP was not associated with increased morbidity compared to SPP. There was a trend towards a longer OS in the TPP group and the finding of residual disease in 'normal looking' peritoneum' warrants prospective evaluation of the benefit of TPP in this setting., (Copyright © 2019 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Introduction: Residual disease in 'normal appearing' peritoneum is seen in nearly 30% of the patients following neoadjuvant chemotherapy (NACT) for advanced ovarian cancer. The goal was to study the sequence of response in different regions, the commonest sites of occult residual disease, its incidence in different peritoneal regions and the potential therapeutic implications of these., Methods: This was a prospective multi-centre study (July 2018-June 2019). Pathological evaluation of cytoreductive surgery specimens was performed according to a fixed protocol. Prevalence of residual disease in different regions was used to study patterns of response and distribution of residual disease., Result: In 85 patients treated between July 2018 to June 2019, microscopic disease in 'normal appearing' peritoneal regions was seen in 22 (25.2%) and in normal peritoneum around tumor nodules in 30 (35.2%) patients. Regions 4 and 8 of Sugarbaker's PCI had the highest incidence of occult disease and regions 9 and 10 the lowest. The response to chemotherapy occurred in a similar manner in over 95%- the least common site of residual disease was the small bowel mesentery, followed by upper regions (regions 1-3), omentum and middle regions (regions 0, 4, 8), lower regions (regions 5-7) and lastly the ovaries., Conclusions: During interval CRS, based on the disease mapping provided in this manuscript, regions that have a high probability of residual disease should be explored and dissected. Complete resection of involved the peritoneal region can completely address the occult disease. The role of resection of the entire region as well as 'normal appearing' parietal peritoneal regions should be prospectively evaluated., Competing Interests: Declaration of competing interest All the authors have no conflict of interests., (Copyright © 2020 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Background: The surgical peritoneal cancer index (sPCI) is calculated based on a subjective evaluation of the extent of peritoneal disease during surgery. The pathologic PCI (pPCI) may be a more accurate and objective method for determining the PCI. This study aimed to compare the sPCI and pPCI and to study the potential pitfalls and clinical implications of using the pPCI., Methods: This prospective study (July to December 2018) included all patients undergoing cytoreductive surgery (CRS). The pPCI was calculated for each patient and compared with the sPCI. The impact of potential confounding factors on the difference between pPCI and sPCI was evaluated., Results: Among 191 patients undergoing CRS at four centers, the pPCI and sPCI were concordant for 37 patients (19.3%). The pPCI was lower than the sPCI for 125 patients (65.4%) and higher for 29 patients (15.1%). The concordance between the two groups was maximum for gastric cancer (38.8%) and colorectal cancer (27.6%) and least for mesothelioma (6.7%) and rare primary tumors (5.6%) (p = 0.04). The difference was 0 to 3 points for 119 patients (62.3%), 4 to 5 points for 27 patients (14.1%), and more than 5 points for 45 patients (23.5%). The rate of concordance was not influenced by the use of neoadjuvant chemotherapy (NACT) (p = 0.4), but the difference was greater when NACT was used (p = 0.03)., Conclusions: The pPCI strongly differs from the sPCI for patients undergoing CRS for peritoneal disease and may provide a more accurate evaluation of the peritoneal disease extent. Further studies are needed to determine its prognostic value compared with sPCI, and consensus guidelines are needed for calculating it.

Background: The aim was to study the patterns of target region (greater omentum, lesser omentum, falciform and umbilical round ligament) involvement in patients undergoing cytoreductive surgery (CRS) from various primary tumors, factors affecting involvement and implications on surgical practice., Methods: All patients undergoing CRS from July 2018 to December 2018 were included in this prospective study. The incidence of target region involvement in presence and absence of visible disease and the impact of primary tumor site, PCI and other variables on target region involvement was evaluated., Results: In 191 patients, greater omentum was involved in over 15% of patients irrespective of the primary tumor type and in 15.7% in absence of visible disease. 75% of these had PCI <20. The involvement of the other three target regions was higher than 20% in ovarian cancer, appendiceal tumors and peritoneal mesothelioma. Involvement of these 3 regions was associated with a higher PCI (p < 0.001 for all) and omental involvement (p < 0.001for all). 2.1% of colorectal cancer patients had umbilical round ligament involvement, 4.2% had falciform ligament involvement and none had lesser omentum involvement., Conclusions: Target region involvement varies according to primary tumour site and disease extent. Resection of the greater omentum should be performed during CRS for PM arising from all primary sites. Resection of other target organs may be performed for selected patients with ovarian cancer, peritoneal mesothelioma and mucinous appendiceal tumors in absence of visible disease. For other patients, it should be done only in presence of visible disease., Competing Interests: Declaration of competing interest The authors have no disclosures or conflict of interests., (Copyright © 2019 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Background and Aim: The grade/histological subtype is one of the most important prognostic markers in patients undergoing cytoreductive surgery (CRS). Our aim was to study other potential prognostic information that can be derived from the pathological evaluation of CRS specimens and provide a broad outline for evaluation of these., Methods: This prospective study (July to December 2018) included all patients undergoing cytoreductive surgery (CRS). A protocol for pathological evaluation was laid down which was based on existing practices at the participating centers and included evaluation of the pathological PCI, regional node involvement, response to chemotherapy, morphology of peritoneal metastases (PM) and distribution in the peritoneal cavity., Results: In 191 patients undergoing CRS at 4 centers, the pathological and surgical PCI differed in over 75%. Nodes in relation to peritoneal disease were positive in 13.6%. Disease in normal peritoneum adjacent to tumor nodules was seen in >50% patients with ovarian cancer and mucinous apppendiceal tumors. 23.8% of evaluated colorectal PM patients had a complete response and 25.0% ovarian cancer patients had a near complete pathological response to chemotherapy., Conclusions: Pathological evaluation of extent and distribution of peritoneal disease differs from the surgical evaluation in majority of the patients. Lymph node involvement in relation of peritoneal disease is common. The morphological presentation of PM in ovarian cancer and mucinous appendiceal tumors merits evaluation of more extensive resections in these patients. Standardized methods of synoptic reporting of CRS specimens could help capture vital prognostic information that may in future influence how these patients are treated., (Copyright © 2019 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Objectives: The goals were to study • The pattern of pathological response to neoadjuvant chemotherapy (NACT) and its clinical implications • The impact of chemotherapy response grade (CRG) on survival METHODS: A retrospective analysis of patients undergoing interval cytoreductive surgery (CRS) between January 2013 to December 2017 was performed. The surgical and pathological reports were analyzed and surgical and pathological PCI compared. The pathological response to chemotherapy was assessed using the score developed by Bohm. et al., Results: In 79 patients, it was observed that sites involved by disease first like ovaries and pelvic peritoneum (lower region) were the last to respond preceded by the omentum, right upper quadrant (RUQ) peritoneum (upper region) and parietal peritoneum (middle region). Microscopic residual disease was seen in 20.2% in normal looking areas of peritoneum and in 20% with no gross residual disease in the RUQ. Visual inspection during surgery overestimated the disease extent in 40.5% and underestimated it in 15.1%. There was no difference in the progression free (p = 0.587) and overall survival (p = 0.157) between patients with CRG 1, 2 and 3 (poor, moderate, and complete/near complete response, respectively). Retroperitoneal nodes were positive in 0% with CRG 3, 27.5% with CRG 2 and 72.7% with CRG 1 (p < 0.0001)., Conclusions: The pathological response to NACT follows a specific pattern. Visual inspection is of limited value in assessing disease extent following NACT. Surgery following NACT should target sites involved before NACT and not just residual disease. The response in regional nodes should be included in chemotherapy response scores., (Copyright © 2019 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Introduction: Peritoneal metastasis (PM) of hepatocellular carcinoma (HCC) without distant spread are rare. The related prognosis is poor without standard treatment available. The role of cytoreduction surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) is poorly documented., Methods: An international multicentric cohort was constituted by retrospective analysis of 21 patients undergoing CRS/HIPEC for PM of HCC between 1992 and 2016 from 10 reference centers of PSOGI. Data on clinical features, treatment strategies, and survival outcomes were analyzed., Results: The median time interval from the diagnosis of PM to the procedure was 4.5 months. The median peritoneal cancer index was 14. Sixteen patients had complete cytoreduction (CCR0-1). Ten patients had grades 3 to 4 complications. The median duration of follow-up was 52.2 months. The median OS was 46.7 months. The projected 3y-OS and 5y-OS were 88.9 and 49.4% respectively. The median OS for patients with CCR0-1 resection was not reached whereas it was 5.9 months for those with CCR2-3 resection after CRS (p = 0.0005). The median RFS was 26.3 months and projected RFS at 3 years of 36.5 months Three prognostic factors were associated with improved RFS in the univariate analysis: preoperative chemotherapy (p = 0.0156), PCI >15 (p = 0.009), Number of chemotherapy agents used for HIPEC (p = 0.005)., Conclusion: CRS/HIPEC is a safe and effective approach in selected patients with PM of HCC. CRS/HIPEC gives the patient a chance for a good relapse free and overall survival and should be considered as an option., (Copyright © 2018 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Introduction: The pathological classification of PMP of appendiceal origin has prognostic and treatment implications. Our goals were to • Classify low grade mucinous carcinoma peritonei (LGMCP) into prognostically distinct subgroups based on histological features. • Compare the reproducibility of the WHO and the PSOGI classifications for both PMP and the appendiceal primary tumor., Patients and Methods: A retrospective analysis of patients undergoing CRS and HIPEC or debulking surgery was done. All the tumors were re-classified according to the PSOGI classification. LGMCP was further classified into three histological subgroups and the impact on survival was evaluated., Results: From Jun 2011 to June 2016, 101 patients underwent CRS with HIPEC (n = 89) or debulking surgery (n=12). The median PCI was 28 (3-39) and 74.1% patients had CC-0/1 resections. Of the 76.2% patients who had LGMCP, 4 patients (5.1%) were classified as group 1, 54 (70.1%) as group 2 and 19 patients (24.6%) as group 3. At a median follow up of 21 months, the disease free survival was not reached, 30 months and 14 months for groups 1, 2 and 3 respectively (p = 0.09). There was no difference in overall survival. Using the WHO classification, there was a discordance in the grade of the primary tumor and the peritoneal lesions in 19.8% and conflicting terminology was used in 62% of patients., Conclusions: The subgroups of LGMCP described here are prognostically different though this needs further prospective evaluation in larger series. The PSOGI classification is more uniformly reproducible and should be preferred to the WHO classification., (Copyright © 2018 Elsevier Ltd, BASO ~ The Association for Cancer Surgery, and the European Society of Surgical Oncology. All rights reserved.)

Purpose: To evaluate the short-term outcomes of patients of pseudomyxoma peritonei (PMP) of appendiceal origin treated with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) at two tertiary Indian centers., Methods: Data was prospectively collected from January 2011 to January 2016. Palliative procedures were excluded. HIPEC was performed by the coliseum technique using either a mitomycin or oxaliplatin-based regimen., Results: 77 procedures were performed on 71 patients. The average time interval between diagnosis and CRS was 15.3 months. Of the tumors, 22.1% were high grade, 77.9% low grade and 24.6% intermediate grade. The median peritoneal carcinomatosis index (PCI) was 26 (<25 in 70.1% and >30 in 38.9%). Completeness of cytoreduction score (CCS)-1 was achieved in 75.3% (CC-0 in 42.9%). The mean number of bowel anastomoses was 1.1 and the mean number of organs resected per patient was 3.3. Of the 77 patients, 71% had resection of 3 or more organs and 50.6% had resection of 4 or more organs. Grade 3-4 complications occurred in 42.9% of the patients and the perioperative mortality was 5.2%. The projected 5-year overall survival (OS) was 62.3% and the 3-year disease-free survival (DFS) was 71% at a median follow up of 13 months., Conclusion: CRS and HIPEC can be used to treat PMP with an acceptable morbidity and mortality in Indian patients. Lack of early referrals leads to a large portion of patients presenting with extensive disease and an inferior survival which should improve with increasing awareness about the procedure and its results.