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e14057 Background: Limited information is available on the role of FDG-PET in the management of patients with mCRC. Bevacizumab prolongs overall survival and progression-free survival (PFS) when ad...

15022 Background: Metastatic spread is the leading cause of colorectal cancer deaths. In a minority of patients, peritoneal carcinomatosis (PC) develops in the absence of distant metastasis. It is ...

Anastomotic leakage (AL) after Ivor Lewis esophagectomy with intrathoracic anastomosis carries a significant morbidity. Adequate perfusion of the gastric tube (GT) is an important predictor of anastomotic integrity. Recently, near infrared fluorescent (NIRF) imaging using indocyanine green (ICG) was introduced in clinical practice to evaluate tissue perfusion. We evaluated the feasibility and efficacy of GT indocyanine green angiography (ICGA) after Ivor Lewis esophagectomy.This retrospective analysis used data from a prospectively kept database of consecutive patients who underwent Ivor Lewis (IL) esophagectomy with GT construction for cancer between January 2016 and December 2020. Relevant outcomes were feasibility, ICGA complications and the impact of ICGA on AL.266 consecutive IL patients were identified who matched the inclusion criteria. The 115 patients operated with perioperative ICGA were compared to a control group in whom surgery was performed according to the standard of care. ICGA perfusion assessment was feasible and safe in all 115 procedures and suggested a poorly perfused tip in 56/115 (48.7%) cases, for which additional resection was performed. The overall AL rate was 16% (43/266), with 12% (33/266) needing an endoscopic our surgical intervention and 6% (17/266) needing ICU support. In univariable and multivariable analyses, ICGA was not correlated with the risk of AL (ICGA:14.8% vs non-ICGA:17.2%, p = 0.62). However, poor ICGA perfusion of the GT predicted a higher AL rate, despite additional resection of the tip (ICGA poorly perfused: 19.6% vs ICG well perfused: 10.2%, p = 0.19).ICGA is safe and feasible, but did not result in a reduction of AL. The interpretation and necessary action in case of perioperative presence of ischemia on ICGA have yet to be determined. Prospective randomized trials are warranted to analyze its benefit on AL in esophageal surgery. Trial registration Ethical approval for a prospective esophageal surgery database was granted by the Ethical committee of the Ghent University Hospital. Belgian registration number: B670201111232. Ethical approval for this retrospective data analysis was granted by our institutional EC.BC-09216.

Quality of health care is a hot topic, especially with regard to cancer. Although rectal cancer is, in many aspects, a model oncologic entity, there seem to be substantial differences in quality of care between countries, hospitals and physicians. PROCARE, a Belgian multidisciplinary national project to improve outcome in all patients with rectum cancer, identified a set of quality of care indicators covering all aspects of the management of rectal cancer. This set should permit national and international benchmarking, i.e. comparing results from individual hospitals or teams with national and international performances with feedback to participating teams. Such comparison could indicate whether further improvement is possible and/or warranted.

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4101 Background: Up to 25% of patients with metastatic CRC present with peritoneal carcinomatosis (PC) as the only site of metastases. The concept of Complete Cytoreductive Surgery (CCRS) followed by Hyperthermia and Intraperitoneal Chemotherapy (HIPEC) was developed, aiming for locoregional disease control and long-term survival. Methods: This prospective multicentre registry included 48 patients (M/F ratio 17/31) with PC from CRC, who underwent CCRS and HIPEC with oxaliplatin(460mg/m2). In 72.9% of patients the primary tumor had been previously resected. Median PCI (peritoneal cancer index) was 11 [1–22], with a median of 6 [1–11] abdominal regions involved and a median lesion size score of 3 [1–3]. In 11 cases associated lymph nodes (63.6% mesenteric, 27.3% para-aortic) were resected. To obtain CCRS a median of 2 [2–6] organs needed to be resected, with anterior resection in 45.8%, total colectomy in 8.3% and small bowel resection in 12.5% of cases. A median of 1 [0–6] anastomosis was performed per patient, of which one third were low and 82.1% were performed after HIPEC. Eleven ileostomies and 5 colostomies were constructed. Results: Median operation time was 460min.[125–840], with a median blood loss of 475ml [2- 6000]. HIPEC posed few procedural problems. There was no postoperative mortality. Complication rate was 52.1%, with 18 intra- and 17 extra-abdominal complications. Anastomotic leakage occurred in 10.4% of patients, bleeding in 6.3% and prolonged ileus in 22.9%. Median hospital stay was 20 [5–65] days. Occurrence of intra-abdominal complications significantly affected hospital stay (p=0.0012), but no risk factors for occurrence of postoperative complications could be clearly identified. Median follow-up was 22.7 [3.2–55.7] months, with 91.7% 2-year overall survival. Progression-free survival at 2 years is 64.6%, with PC recurrence in 29.2% of patients and other metastatic disease in 25%. Multivariate analysis only retained the CEA-level as a significant prognostic factor (p=0.0065). Conclusions: CCRS followed by HIPEC for PC of colorectal origin is safe and has longer than expected PFS and OS. No significant financial relationships to disclose.

Mucinous appendiceal tumors with or without the pseudomyxoma peritonei (PMP) syndrome are rare, but often present as an incidental finding. The confusing histology and lack of large prospective trials result in a considerable diagnostic and therapeutic challenge in these patients. We propose treatment algorithms in patients with incidentally found mucinous epithelial appendiceal tumors, with or without PMP, based on the currently available evidence. The therapeutic approach should take into account the histology and grade of the primary appendix tumor, as well as those of the associated peritoneal disease.

Background: The aim of the study was to evaluate the influence of low dose perioperative Octreotide on the prevention of complications (pancreatic fistula and general complications) in patients undergoing pancreatic surgery followed by pancreatico-jejunostomy. Material and Methods : 105 patients were randomized to receive either Octreotide 0.1 mg subcutaneously 3 times/day for a total of 7 days or no Octreotide. The primary endpoints were the occurrence of a pancreatic fistula and/or general complications including the length of hospital stay. There were 25 surgical draining procedures performed and 80 duodeno-pancreatectomies with or without preservation of the pylorus. Twenty-six (24.8%) of the patients were treated for chronic pancreatitis, 8 (7.6%) for benign tumoral disease and 71 (67.6%) for carcinoma. All patients underwent pancreatico-jejunostomy. Results : 56 patients received Octreotide and 49 did not. The incidence of fistula formation in the Octreotide group was 8.9% (n = 5) and in the control group 8.2% (n = 4) for a total incidence of 8.5%. The difference between the two groups was not statistically significant. There was one death in the Octreotide group and none in the control group for an overall mortality of 0.9%. The morbidity, except fistulas, was 10.7% in the Octreotide group and 12.2% in the control group. The length of hospital stay was 23.1 +/- 15.1 days in the group receiving Octreotide vs 20.4 +/- 8.1 days in the control group (p = 0.808). Stratifying the data for duodenopancreatectomy and for draining procedures there was no difference between the groups either. Conclusion : In patients undergoing pancreatic surgery and pancreatico-jejunostomy, the perioperative use of 3 x 0.1 mg Octreotide for 7 days does not reduce general complications nor fistula formation.

The persistence of residual tumour is associated with the histology and stage of the primary cancer, the completeness and quality of surgery, and postoperative events such as anastomotic leakage or entrapment of cells in exudating wound surfaces. At present, there is no clinical evidence that the use of laparoscopic techniques adversely influences the risk of residual disease. The inflammatory process associated with surgery shares a number of central mediators and pathways with tumour growth and invasiveness. Both cellular components (mainly macrophages and fibroblasts) and humoral factors associated with inflammation have been shown to enhance tumour growth in numerous preclinical studies. Tumour foci at a distance from the main cancer are kept in a dormant state by a range of anti-angiogenic mediators produced by the main cancer. Preclinical studies have shown that removal of the primary cancer reactivates proliferative and metastatic pathways in the residual tumour. Clinically, this phenomenon has been proposed as underlying the observed rapid systemic relapse after surgery in young node positive breast cancer patients. Strategies proposed to prevent residual disease encompass avoidance of tumour spill and minimization of surgical trauma and related inflammation. Efforts to remove or kill free intraperitoneal cells by local antiseptic or cytotoxic regimens have met only limited clinical success. Specific targeted therapy aimed at inhibiting the inflammatory response, tumour cell adhesion, or the metastatic phenotype of dormant cells appears promising in preclinical models and needs to be addressed in future clinical trials.

Resistance against drug delivery is a challenge in oncology. The elevated interstitial fluid pressure (IFP) in solid tumors has been identified as a barrier for drug transport. Also, the hydraulic conductivity (K) of tumor stroma strongly correlates with the IFP. However, values of K in human cancer tissue are not available. Here, we developed a novel in vitro setup that allows to measure K in clinical samples.

Recent insights have implicated mesothelial-to-mesenchymal transition (MMT) as a mechanism by which mesothelial cells can transdifferentiate into cancer-associated fibroblasts (CAFs) in several cancers metastasizing to the peritoneum. However, this was not evaluated extensively in colorectal cancer. We examined the presumed mesothelial origin of CAFs in three types of colorectal carcinoma: conventional type adenocarcinoma, mucinous carcinoma and signet ring cell carcinoma. We evaluated the expression of mesothelial, mesenchymal, angiogenesis and colorectal cancer-related markers in peritoneal samples of twelve colorectal cancer patients with peritoneal carcinomatosis and four control patients by immunohistochemistry. We observed morphological and immunohistochemical changes in the vicinity of tumor implants in all studied colorectal cancer types. Mesothelial cells acquired a spindle-shaped myofibroblast-like morphology, lost expression of mesothelial markers, and gained expression of mesenchymal markers. Analysis of consecutive tissue sections and double staining for mesothelial and mesenchymal markers revealed overlap in expression of mesothelial and CAF markers. These findings are highly suggestive of a mesothelial origin of CAFs in peritoneal carcinomatosis in colorectal cancer. Interfering with the process of MMT might be a valuable approach in treating and preventing peritoneal carcinomatosis. Differences observed between colorectal cancer types suggest that one single strategy might not be applicable.

Background : Surgery has traditionally been learned on patients in the operating room, which is time-consuming, can have an impact on the patient outcomes, and is of variable effectiveness. As a result, surgical training models have been developed, which are compared in this systematic review. Methods : We searched Pubmed, CENTRAL, and Science Citation index expanded for randomised clinical trials and randomised cross-over studies comparing laparoscopic training models. Studies comparing one model with no training were also included. The reference list of identified trials was searched for further relevant studies. Results : Fifty-eight trials evaluating several training forms and involving 1591 participants were included (four studies with a low risk of bias). Training (virtual reality (VR) or video trainer (VT)) versus no training improves surgical skills in the majority of trials. Both VR and VT are as effective in most studies. VR training is superior to traditional laparoscopic training in the operating room. Outcome results for VR robotic simulations versus robot training show no clear difference in effectiveness for either model. Only one trial included human cadavers and observed better results versus VR for one out of four scores. Contrasting results are observed when robotic technology is compared with manual laparoscopy. Conclusion : VR training and VT training are valid teaching models. Practicing on these models similarly improves surgical skills. A combination of both methods is recommended in a surgical curriculum. VR training is superior to unstructured traditional training in the operating room. The reciprocal effectiveness of the other models to learn surgical skills has not yet been established.