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

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

Background Complete cytoreductive surgery of macroscopic tumor is a potentially curative treatment for patients with colorectal peritoneal metastases. Objective This study aims to determine the risk of microscopic tumor involvement of the greater omentum in patients with normal-looking omentum at the time of cytoreductive surgery for colorectal peritoneal metastases. Design This was a cohort study. Settings The prospective BIG-RENAPE database (NCT02823860) was analyzed. Patients All patients who underwent a complete cytoreductive surgery with greater omentectomy for colorectal peritoneal metastases at a single institution between January 2005 and December 2017 were included. Main outcome measure Data regarding involvement of the greater omentum were extracted from surgical and pathological records. Results Of 337 patients who underwent cytoreductive surgery for colorectal peritoneal metastases, 241 (71.51%) presented macroscopic omental invasion. Among the 96 patients who underwent a complete cytoreductive surgery with no macroscopic evidence of disease in the greater omentum during surgical exploration, 17 patients (17.70%) had microscopic evidence of tumor in the omentum. Patients with pathological evidence of omental tumor involvement were more likely to have a higher peritoneal cancer index (median 9 vs 4, p = 0.006). Limitations No survival analysis could be provided regarding the impact of omentectomy. Conclusion In patients with a normal-looking omentum during surgery for colorectal peritoneal metastases, microscopic tumor was present in 17%. Routine greater omentectomy should be considered in these patients to ensure complete cytoreduction. See Video Abstract at http://links.lww.com/DCR/B262.ClinicalTrials.gov Identifier: NCT02823860 RIESGO DE METASTASIS OMENTALES EN PACIENTES SOMETIDOS A CIRUGIA CITORREDUCTORA, POR METASTASIS PERITONEALES COLORRECTALES: La cirugia citorreductora completa del tumor macroscopico, es un tratamiento potencialmente curativo, en pacientes con metastasis peritoneales colorrectales.Determinar el riesgo de afectacion tumoral microscopica del epiplon mayor, en pacientes con epiplon de aspecto normal, al momento de la cirugia citorreductora por metastasis peritoneales colorrectales.Este fue un estudio de cohorte.Se analizo la base de datos prospectiva BIG-RENAPE (NCT02823860).Se incluyeron a todos los pacientes sometidos a una cirugia citorreductora completa con omentectomia mayor, por metastasis peritoneales colorrectales, de una sola institucion, entre enero de 2005 y diciembre de 2017.Se extrajeron los datos de la afectacion del epiplon mayor, de los registros quirurgicos y patologicos.De 337 pacientes sometidos a cirugia citorreductora por metastasis peritoneales colorrectales, 241 (71.51%) presentaron invasion omental macroscopica. Entre los 96 pacientes sometidos a cirugia citorreductora completa, sin evidencia macroscopica de enfermedad en el epiplon mayor, durante la exploracion quirurgica, 17 pacientes (17,70%) tuvieron en el epiplon, evidencia microscopica de tumor. Los pacientes con evidencia patologica de afectacion del tumor omental, fueron mas propensos a tener un indice de cancer peritoneal mas alto (mediana 9 frente a 4, p = 0,006).No se pudo obtener ningun analisis de supervivencia, sobre el impacto de la omentectomia.En pacientes con epiplon de aspecto normal, durante la cirugia por metastasis peritoneales colorrectales, estuvo presente el tumor microscopico, en el 17% de los casos. Se debe considerar una omentectomia mayor de rutina en estos pacientes, para asegurar una citorreduccion completa. Consulte Video Resumen http://links.lww.com/DCR/B262.Identificador de ClinicalTrials.gov: NCT02823860.

Computed tomography imaging plays a major role in the preoperative assessment of tumor burden by providing an accurate mapping of the distribution of peritoneal metastases (PM). Spectral Photon Counting Computed Tomography (SPCCT) is an innovative imaging modality that could overcome the current limitations of conventional CT, offering not only better spatial resolution but also better contrast resolution by allowing the discrimination of multiple contrast agents. Based on this capability, we tested the feasibility of SPCCT in the detection of PM at different time of tumor growth in 16 rats inoculated with CC531 cells using dual-contrast injection protocols in two compartments (i.e. intravenous iodine and intraperitoneal gadolinium or the reverse protocol), compared to surgery. For all peritoneal regions and for both protocols, sensitivity was 69%, specificity was 100% and accuracy was 80%, and the correlation with surgical exploration was strong (p = 0.97; p = 0.0001). No significant difference was found in terms of diagnostic performance, quality of peritoneal opacification or diagnostic quality between the 2 injection protocols. We also showed poor vascularization of peritoneal metastases by measuring low concentrations of contrast agent in the largest lesions using SPCCT, which was confirmed by immunohistochemical analyses. In conclusion, SPCCT using dual-contrast agent injection protocols in 2 compartments is a promising imaging modality to assess the extent of PM in a rat model.

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

Background: Gastric cancer (GC) is associated with a poor prognosis mostly due to peritoneal metastasis, which will develop in time during the patient’s disease history. To prevent and treat peritoneal metastasis, different kinds of treatment regimens have been described. Summary: In this review, we addressed two main topics – prophylaxis and treatment of peritoneal metastasis in GC. Prevention should be directed towards diminishing cancer cell spillage and reducing adherence of cancer cells to the abdominal cavity. Postoperative washing of the abdomen with or without chemotherapy and additional heat are herein discussed. Key Messages: Treatment of existing peritoneal metastasis is effective in patients with limited disease and tumour spread. Cytoreductive surgery including resection of peritoneal metastasis followed directly with hyperthermic intraperitoneal chemotherapy can increase overall survival and progression-free survival in selected patients. Drugs, duration and time schedules of intraperitoneal chemotherapy are reviewed and presented. Intraperitoneal chemotherapy seems to improve the prognosis of patients with GC and peritoneal metastasis after complete resection of both primary and metastatic tumours.

Simple Summary Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy improves survival in selected patients with peritoneal metastases from colorectal cancer (CRC). However, the characteristics of long-term survivors are not well documented. This study set out to investigate the patient characteristics associated with the long-term survival of peritoneal metastases from CRC. We retrospectively analyzed 206 long-term survivors who underwent CRS for peritoneal metastases from CRC. We found that most long-term survivors showed low peritoneal cancer index (PCI), low PCI of small bowel subsets, and complete cytoreduction (CC-0), while some exhibited characteristics considered associated with poor prognosis. Abstract Background: We conducted this study to review the patient characteristics associated with long-term survival in patients with peritoneal metastases from colorectal cancer who underwent cytoreductive surgery (CRS). Methods: We retrospectively investigated patients with peritoneal metastases from CRC treated with curative intent surgery with or without hyperthermic intraperitoneal chemotherapy at 13 institutions worldwide between January 1985 and April 2015 and survived longer than five years after the first CRS for peritoneal metastases. Clinical and oncological features and therapeutic parameters were described and analyzed. Results: Two hundred six long-term survivors were available for study. The median peritoneal cancer index (PCI) of this cohort was 4 (interquartile range (IQR), 2–7), and the median score of the small bowel regions of the PCI (SB-PCI) was 0 (IQR, 0–2). Complete cytoreduction (CC-0) was achieved in 180 (87.4%) patients. Recurrence was observed in 122 (59.2%) patients at a median of 1.8 (IQR, 1.2–2.6) years. Conclusions: While most long-term survivors showed low PCI/SB-PCI and CCR-0, some had characteristics considered associated with poor prognosis. Curative intent treatments may be considered in well-informed and fit patients showing negative factors affecting survival outcome.

Resume Les tumeurs primitives malignes du peritoine et les metastases ou carcinoses peritoneales ont ete longtemps considerees comme un stade metastatique terminal. Le developpement de nouvelles techniques de chirurgie de cytoreduction et peritonectomies, de chimiotherapie intraperitoneale associee ou non a l’hyperthermie, la mise en place de centres specialises dans la prise en charge de ces pathologies a considerablement modifie le pronostic de ces pathologies. Autrefois condamnes a court terme, certains patients selectionnes sur leur etat general, l’origine, l’extension et la resecabilite de leur carcinose peritoneale peuvent beneficier d’un traitement curatif. Le facteur pronostique principal, quelle que soit l’etiologie de la carcinose peritoneale est represente par la possibilite de pouvoir realiser une chirurgie de cytoreduction complete associant resection d’organes et peritonectomies. En moins de trois decennies, la mediane de survie des patients avec metastases peritoneales est passee de 5 a 40 mois pour celles d’origine colorectale, de 3 a 25 mois pour celles d’origine gastrique. Cette mediane de survie n’est pas atteinte pour les pseudomyxomes peritoneaux et est superieure a 50 mois pour les mesotheliomes peritoneaux malins. Ces traitements chirurgicaux lourds et complexes necessitent une prise en charge multidisciplinaire specialisee et doivent etre realises dans un nombre limite de centres experts afin de mieux selectionner les candidats a une prise en charge curative, de limiter la mortalite et morbidite des procedures chirurgicales et d’optimiser la prise en charge perioperatoire et la qualite de vie.

Introduction Surgical management of Diaphragmatic and thoracic endometriosis (DTE) is still controversial, a thoracic or an abdominal approach can be proposed. Methods We conducted a multicentric retrospective study in 8 thoracic, gynecology or digestive surgery units in 5 French university hospitals. The main objective was to review the current management of DTE. Results 50 patients operated for DTE from 2010 to 2017 were included: 26 with a thoracic approach and 24 with an abdominal approach. Preoperative pelvic endometriosis (PE) concerned 25 patients. In 38 patients, DTE diagnosis was made on clinical symptoms (pneumothorax (n = 19), chronic or catamenial chest pain (n = 18) or hemopneumothorax (n = 1)). Median time from onset of symptoms to diagnosis was 47 months (0–212). PE surgery concurrently occurred in 22 patients. We report diaphragmatic nodules, pleuropulmonary nodules and diaphragmatic perforations in 42, 5 and 22 women respectively. Lesions were right-sided in 45 patients. Nodules were destructed in 12 cases and resected in 38 cases. When a diaphragmatic reconstruction was needed (n = 31), a simple suture was performed in 26 patients, while 5 patients needed a mesh repair. Pleural symphysis was performed for all patients who received a thoracic approach. DTE resection was considered complete in 46 patients. Three patients had severe 30-days complications of DTE surgery. Median follow-up was 20 months (range 1–69). Recurrence occurred in 10 patients. Conclusion The results emphasize the importance of systematically looking for chest pain in patients suffering from PE and underline the lack of a standardized procedure and treatment in DTE.

Background PIPAC is a recent approach with promising results for patients with peritoneal metastasis (PM). We aimed to evaluate survival and postoperative outcome of patients with unresectable PM from gastric origin treated with chemotherapy and PIPAC. Methods A retrospective analysis of a prospective maintained PIPAC database was queried for all patients diagnosed with unresectable PM from gastric cancer who underwent PIPAC before 2018. PIPAC with Cisplatin 7.5 mg/m2 and doxorubicin 1.5 mg/m2 were given for 30 min at 6-week intervals. Outcome criteria were overall survival and adverse events according to (CTCAE) version4.0. Results One hundred Sixty-three PIPAC were done in 42 consecutive patients. Twenty-two (52%) of the patients were female. Signet-ring cells were observed in 33/42 patients (78.6%). At the first PIPAC, median age was 51.5 years (32–74). Median PCI was 17 (1–39). Twenty (47.6%) patients underwent more than 2 lines of pre-PIPAC chemotherapy. All patients had systemic chemotherapy alternating with PIPAC. Median consecutive PIPAC procedures were 3 (1–12). Overall and major complications (CTCAE - III, IV) occurred in 10 (6.1%) and 5 procedures (3.1%), respectively. Two patients (4.7%) died within 30 days of a PIPAC procedure, one related to small bowel obstruction and a pulmonary embolism for the other. Overall Survival was 19.1 months. Six (14.3%) patients became resectable during treatment and underwent curative intent CRS and HIPEC. Conclusions PIPAC with low-dose cisplatin and doxorubicin is safe and feasible in association with systemic chemotherapy for gastric PM. Survival data are encouraging and justify further clinical studies in this indication.

PURPOSE Gastric cancer (GC) with peritoneal metastases (PMs) is a poor prognostic evolution. Cytoreductive surgery (CRS) yields promising results, but the impact of hyperthermic intraperitoneal chemotherapy (HIPEC) remains controversial. Here we aimed to compare outcomes between CRS-HIPEC versus CRS alone (CRSa) among patients with PMs from GC. PATIENTS AND METHODS From prospective databases, we identified 277 patients with PMs from GC who were treated with complete CRS with curative intent (no residual nodules > 2.5 mm) at 19 French centers from 1989 to 2014. Of these patients, 180 underwent CRS-HIPEC and 97 CRSa. Tumor burden was assessed using the peritoneal cancer index. A Cox proportional hazards regression model with inverse probability of treatment weighting (IPTW) based on propensity score was used to assess the effect of HIPEC and account for confounding factors. RESULTS After IPTW adjustment, the groups were similar, except that median peritoneal cancer index remained higher in the CRS-HIPEC group (6 v 2; P = .003). CRS-HIPEC improved overall survival (OS) in both crude and IPTW models. Upon IPTW analysis, in CRS-HIPEC and CRSa groups, median OS was 18.8 versus 12.1 months, 3- and 5-year OS rates were 26.21% and 19.87% versus 10.82% and 6.43% (adjusted hazard ratio, 0.60; 95% CI, 0.42 to 0.86; P = .005), and 3- and 5-year recurrence-free survival rates were 20.40% and 17.05% versus 5.87% and 3.76% ( P = .001), respectively; the groups did not differ regarding 90-day mortality (7.4% v 10.1%, respectively; P = .820) or major complication rate (53.7% v 55.3%, respectively; P = .496). CONCLUSION Compared with CRSa, CRS-HIPEC improved OS and recurrence-free survival, without additional morbidity or mortality. When complete CRS is possible, CRS-HIPEC may be considered a valuable therapy for strictly selected patients with limited PMs from GC.

e16538 Background: Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is emerging as a new intraperitoneal laparoscopic delivery of chemotherapy to treat peritoneal metastasis (PM). First results from several malignancies appear promising in small series of patients. Prognosis of PM from gastric cancer (GC) is poor. Median survival is ranging from 3 to 13 months with systemic chemotherapy (SC) alone. Purpose: to evaluate the feasibility and potential benefits of PIPAC associated to SC in GC with PM in a palliative setting Methods: From a prospective database, we identified 91 consecutive patients considered with isolated unresectable PM from GC treated by an alternance of SC and PIPAC with low-dose cisplatin-doxorubicin (ratio 2/1) between January 2016 and January 2019 in our institution. End of follow-up was January 2020. Results: Median age was 56 years, 86% of patients had a signet ring cell adenocarcinoma with 86.7% of synchronous PMs.Median Peritoneal Cancer Index was 16 (3-39). A total of 346 PIPAC were performed with a median of 3 per patient (1-18). Median number of SC lines was 3 (2-3) resulting in a median number of SC cycles of 14 (11-20). After a median follow-up of X months, 21 patients were still alive. In the whole population, median OS from diagnosis was 15.1 months. PIPAC was introduced in association to first-line SC as maintenance or intensification therapy in 75 patients with a median survival from diagnosis of 14.7 months and a median PFS from PIPAC introduction of 6.3 months. For 16 patients, PIPAC was introduced due to progression after a first or second line of SC leading to a median OS of 20 months after diagnosis and 5.9 months after PIPAC introduction. Reasons to stop PIPAC were cancer progression, intraperitoneal access difficulties or PIPAC related morbidity, a cytoreductive surgery attempt in 61.7%, 19.8% and 18.5% respectively. A cytoreduction and HIPEC attempt was performed for 12 patients before 3 PIPAC and 3 after 3 PIPAC or more, leading to a median OS of 19 months for those patients. Twelve (13,2%) patients developed extra-peritoneal metastases during PIPAC. Conclusions: PIPAC appears safe and feasible showing promising results in control of PMs from gastric origin. Further randomized studies are required to document its benefits compared to SC alone.

Supplemental digital content is available in the text., Objectives To validate in vitro the capability of a high-spatial-resolution prototype spectral photon-counting computed tomography (SPCCT) scanner to differentiate between 2 contrast agents and to assess in vivo the image quality and the feasibility to image the peritoneal cavity in rats using the 2 contrast agents simultaneously within the vascular and peritoneal compartments. Materials and Methods The authors performed SPCCT imaging (100 mAs, 120 kVp) with energy bin thresholds set to 30, 51, 64, 72, and 85 keV in vitro on a custom-made polyoxymethylene cylindrical phantom consisting of tubes with dilutions of both contrast agents and in vivo on 2 groups of adult rats using 2 injection protocols. Approval from the institutional animal ethics committee was obtained. One group received macrocylic gadolinium chelate intraperitoneal (IP) and iodine intravenous (IV) injections (protocol A, n = 3), whereas the second group received iodine IP and gadolinium IV (protocol B, n = 3). Helical scans were performed 35 minutes after IP injection and 20 seconds after IV injection. The SPCCT and contrast material images, that is, iodine and gadolinium maps, were reconstructed with a field of view of 160 mm, an isotropic voxel size of 250 μm, and a matrix size of 640 × 640 pixels using a soft reconstruction kernel. The SPCCT images were reconstructed with 2 different spatial resolutions to compare the image quality (sharpness, diagnostic quality, and organ visualization) of SPCCT (250 μm) with single-energy computed tomography (CT) (600 μm). Two radiologists evaluated the peritoneal opacification index in 13 regions (score = 0–3 per region) on each type of image. Concentrations of contrast agents were measured in the organs of interest. Results In vitro, the concentration measurements correlated well with the expected concentrations. The linear regressions both had R2 values of 0.99, slopes of 0.84 and 0.87, and offsets at −0.52 and −0.38 mg/mL for iodine and gadolinium, respectively. In vivo, the SPCCT images were of better diagnostic quality, with increased sharpness compared with the CT-like images (P < 0.0001). Intraperitoneal diffusion was excellent, with similar peritoneal opacification index on SPCCT images and overlay of contrast material maps (P = 1) without a significant difference between protocol A (37.0 ± 1.7) and protocol B (35.3 ± 1.5) (P = 0.34). Only the contrast material maps demonstrated clear visual separation of the contrast agents, allowing specific quantification of the physiological enhancement in the liver, spleen, and kidney and the urinary clearance in the renal pelvis and bladder. Renal excretion of the contrast agents injected IP was observed and was consistent with blood diffusion. Conclusions Spectral photon-counting CT can be used to perform a complete peritoneal dual-contrast protocol, enabling a good assessment of the peritoneal cavity and abdominal organs in rats.

Somatic mutation status in metastatic colorectal cancer (CRC), and namely mutational activation of the Kirsten rat sarcoma viral oncogene homolog (KRAS) oncogene, is becoming more and more relevant in clinical practice. In this review, we describe the current data about the importance of associations between the mutational activation status of the KRAS oncogene and clinical outcomes, prognosis and metastatic patterns of CRC. The presence of a KRAS mutation is detected in approximately 30-50% of CRC and represents a powerful predictor of oncologic outcomes. It is associated with low response to systemic chemotherapy and for insensitivity to the anti-EGFR antibodies in the preoperative setting. It is more frequently associated with right colon cancer. In non-metastatic patients, KRAS mutation leads to more aggressive disease with shorter recurrence free survival (RFS) and more lung recurrences. After resection of CRC liver metastases (LiM), KRAS mutation is directly associated with increased risk of recurrence, worse overall survival (OS), and a distinct metastatic pattern with more invasive intrahepatic recurrence and increased recurrence outside of the liver, particularly in the lung, the peritoneum, and even in uncommon metastatic sites such as the brain and bones. As metastasectomy with curative intent is increasingly considered, a comprehensive approach of tumor biology is required to face the specific challenge of patients with metastatic CRCs. Thus, as it represents one of the strongest predictors of oncologic outcomes, integrating the KRAS mutational status at all the different stages of patient care appears crucial in order to adapt both medical and surgical strategies.

4073Background: Incidence of gastric signet-ring cell adenocarcinoma (SRCa) is increasing. Linitis plastica (LP) is its typical presentation. SRCa are associated with less chemosensitivity and more...

e16093Background: Lymph node status (LNS) drives prognosis of gastric cancer. Peritoneal carcinomatosis (PC) is a stage IV regardless of the LNS and associated with poor prognosis. For selected pat...

149 Background: PIPAC is a recent approach for intraperitoneal chemotherapy with promising results for patients with peritoneal carcinomatosis (PC). We aimed to evaluate survival and postoperative outcome of PIPAC in patients with non-resectable PC from gastric cancer. Methods: This is a retrospective analysis. Sixty-nine PIPAC were applied in 22 consecutive patients pretreated non-resectable PC from gastric cancer. All patients had undergone previous lines of systemic chemotherapy (median, two lines). Cisplatin 7.5 mg/m2 and doxorubicin 1.5 mg/m2 were given for 30 min at 37 °C and 12 mmHg at 6-week intervals.The treatment schedule proposed alternating 2 systemic chemotherapy followed by 1 PIPAC cycles. Outcome criteria were survival, adverse events according to Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Results: At the time of the first PIPAC, the median PCI was 18 (1-35). Median consecutive PIPAC cycles were 4 (1-9). Survival time was 19.5 months. Major complications (CTCAE - III, IV) occurred for 6 PIPAC (8.7%) and 1 (4.5%) patients died within 30 days of the PIPAC procedure a cause related to aspiration pneumonia during the general anesthesia. Systemic chemotherapy was associated with PIPAC and could be administered after PIPAC with a median delay of 14 days (7-28). Conclusions: PIPAC with low-dose cisplatin and doxorubicin was safe and feasible in association with systemic chemotherapy. Survival data are encouraging and justify further clinical studies in this indication.

8 Background: Gastric cancer with peritoneal carcinomatosis (PC) is considered by most as an end-stage disease. Poor outcomes are achieved with palliative chemotherapy. Aggressive combination of cytroreductive surgery (CRS) and Hyperthermic Intraperitoneal Chemotherapy (HIPEC) are still debated in this indication. Purpose: to assess the impact of HIPEC on survival and postoperative outcomes after complete CRS compared with CRS alone (CRSa) Methods: Data from 277 consecutive patients treated for gastric cancer with PC in 19 French centers from 1989 to 2014 were collected. 180 patients who underwent CRS and HIPEC were compared to 97 treated by CRSa. Extension of PC was assessed by the Peritoneal Cancer Index (PCI). Only patients treated by complete CRS were included (CC-0 or CC-1). To assess the effect of HIPEC and to account for confounding factors, a Cox proportional hazards regression model with inverse probability of treatment weighting (IPTW) based on propensity score was used. Multivariate models and sensitivity analyses were also performed. Results: After propensity weighting, groups were similar except for the PCI that remained higher in the HIPEC group (median: 6 v 2, P = .003). However, there was no difference in the completeness of CRS (CC-0: 76.7% v 83.5 %, P = .904). HIPEC was associated with improved overall survival (OS) on both multivariate and IPTW models. On IPTW analysis, median OS was 18.8 v 12.1 months. 3- and 5-years OS were 26.21% and 19.87% v 10.82% and 6.43% (HR, 1.66; 95% CI, 1.17-2.37; P = .005). 3- and 5-years disease-free survival were 20.40% and 17.05% v 5.87% and 3.76% (P = .001). Mortality rate (7.4% v 10.1%, P = .820) and grade 3-4 morbidity (53.7% v 55.3%, P = .496) at 90 days were similar. Surgical morbidity was 37.1% v 38.8% in CRSa group. Conclusions: Compared to CRSa, HIPEC was associated with increased OS and potential disease eradication for gastric cancer with PC, without additional morbidity. This treatment, when optimal CRS can be achieved, should be considered as the gold standard since outcomes remain grim with chemotherapies. Clinical trail information: NCT03253939