P-OGC55 Current treatment modalities and median survival for patients with gastric and oesophagogastric cancers with isolated peritoneal metastasis

Background Gastric cancer with peritoneal metastases carries a median survival of only 3-7 months without treatment. Meanwhile, cancers arising from the oesophago-gastric junction (OGJ) are rapidly increasing in incidence in the Western population and are also commonly associated with peritoneal metastases. In order to measure the efficacy of emerging modes of treatment for peritoneal disease, it is essential to describe the treatments patients currently receive and the impact of these on survival – data for which is poorly described in the literature and lacking in the UK setting. Methods This was a single hospital-based retrospective cohort study covering the period from March 2012 to January 2020 at a tertiary referral centre. 50 patients were identified from multidisciplinary team (MDT) meeting records receiving a diagnosis of gastric adenocarcinoma with isolated peritoneal disease. 31 patients were identified receiving a diagnosis of true (Siewert II or III) junctional adenocarcinoma with isolated peritoneal disease. We calculated median survival time for all patients and also by treatment modality. Results Mean age of patients with gastric adenocarcinoma and isolated peritoneal disease was 71 years (range 44-90). Overall median survival was 6.6 months (IQR 2.4-19.3). Median survival was 11.2 months (IQR 3.7-21.5) for patients receiving systemic chemotherapy (n = 26) and 2.4 months (IQR 1.2-5.1) for patients receiving best supportive care alone (n = 15). Mean age of patients with junctional adenocarcinomas and isolated peritoneal disease was 70 years (range 37-89). Overall median survival was 7 months (IQR 3-19). Median survival was 10.5 months (IQR 6.5-20.5) for patients receiving systemic chemotherapy (n = 20) and 3.5 months (IQR 2-6) for patients receiving best supportive care alone (n = 6). Conclusions Our results demonstrate the poor prognosis of both gastric and oesophagogastric cancer patients with isolated peritoneal disease. Prognosis figures are comparable between the two cancer types. Findings are in line with previous studies performed outside the UK which have shown that available treatments extend survival by no more than 3-9 months, highlighting the desperate need for new treatment modalities.

P-OGC59 Pattern of recurrence following neoadjuvant treatment and two-stage oesophagectomy for oesophageal/junctional adenocarcinoma: 10-year results from a high-volume centre

Background Disease recurrence remains high following oesophagectomy for oesophageal and junctional adenocarcinoma in spite of the incremental gains from improved neoadjuvant treatment (NAT). Follow-up remains important for the detection and treatment of recurrence, although the optimum surveillance strategy remains undefined. Recurrence after treatment can occur locoregionally, distantly, or a combination of both. This retrospective review of a single, high-volume centre’s 10-year experience has sought to determine the pattern of recurrence in those who have received curative NAT followed by two-stage subtotal oesophagectomy (2S-STO) for oesophageal and junctional adenocarcinoma. Methods A retrospective analysis was performed on a cohort of patients from a high-volume, single centre between January 2009 and January 2019 who had confirmed disease recurrence after receiving NAT and 2S-STO for either oesophageal or junctional (Siewert I/II) adenocarcinoma. The Unit’s prospectively collected cancer database was utilised as well as patients’ notes to determine the pattern of recurrence seen in this cohort. Patients receiving a three-stage or transhiatal oesophagectomy for any cause, or those diagnosed with squamous cell carcinoma were excluded. Results 215 patients were identified with recurrence following NAT and 2S-STO for oesophageal/junctional adenocarcinoma within the 10-year period. The median age was 69 (range 23-85) with 67% being male and 33% female. The median time to diagnosis of recurrence was 13 months following surgery. 87 (40%) patients were diagnosed with locoregional recurrence, with the commonest pattern being in mediastinal or abdominal lymph nodes, followed by peritoneal disease. 62 (29%) patients were diagnosed with distant recurrence, with the vast majority being in the liver or lungs. 66 (31%) patients had evidence of both locoregional and distant spread at diagnosis of recurrence. Conclusions The incidence of recurrence following curative treatment for oesophageal and junctional adenocarcinoma remains high. Locoregional disease appears to be the commonest pattern of recurrence as identified in this study, which would confirm spread predominates via the lymphatic and transcoelomic routes. Liver and lung remain the commonest sites for haematogenous spread, although other sites include adrenal, brain and bone. Although the optimum follow-up strategy remains undefined in such patients, timely investigation of symptoms is required for early diagnosis so as to optimise the benefits of palliative treatment.

Peritoneal disease: key imaging findings that help in the differential diagnosis

The peritoneum is a unique serosal membrane, which can be the site of primary tumors and, more commonly, secondary pathologic processes. Peritoneal carcinomatosis is the most common malignant process to affect the peritoneal cavity, and the radiologist plays an important role in making the diagnosis and assessing the extent of disease, especially in sites that may hinder surgery. In this review we address the role of the radiologist in the setting of peritoneal pathology, focusing on peritoneal carcinomatosis as this is the predominant malignant process, followed by revising typical imaging findings that can guide the differential diagnosis. We review the most frequent primary and secondary peritoneal tumor and tumor-like lesions, proposing a systemic approach based on clinical history and morphological appearance, namely distinguishing predominantly cystic from solid lesions, both solitary and multiple.

Diagnostic Laparoscopy in Patients With Peritoneal Carcinomatosis Is Safe and Does Not Delay Cytoreductive Surgery With Hyperthermic Intraperitoneal Chemotherapy

Background Outcomes of cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC) among patients with peritoneal carcinomatosis (PC) depend largely on the extent of peritoneal disease. Since PC is not reliably evaluated with cross-sectional imaging, tumor burden is often evaluated with diagnostic laparoscopy (DLS). The aims of this study are to evaluate the safety of DLS in patients with peritoneal disease and determine if DLS delays time to CRS-HIPEC. Methods We performed an institutional retrospective review of 145 patients who underwent CRS-HIPEC between 2013 and 2020. Patients were divided into 2 groups: those who underwent an electively scheduled DLS prior to CRS-HIPEC and those who did not. Intraoperative and postoperative complications associated with DLS were determined from the surgeon’s operative report. Time from diagnosis of PC to CRS-HIPEC was compared between the 2 groups. Results Of the 145 patients available for analysis, 47% (68) underwent DLS and 44% (64) did not. Of all the diagnostic laparoscopies performed, there was 1 (1.5%) intraoperative complication. The duration between diagnosis of peritoneal carcinomatosis and surgery was 4.9 months among patients who underwent DLS prior to CRS-HIPEC and 4.3 months among patients who did not ( P = .79). Conclusion In this retrospective analysis, diagnostic laparoscopy prior to CRS-HIPEC demonstrated a comparable rate of DLS-associated complications compared to other gastrointestinal malignancies and does not prolong time from diagnosis to CRS-HIPEC. Thus, in patients undergoing evaluation for CRS-HIPEC, diagnostic laparoscopy provides significant value in patient selection without incurring perioperative risk or delay in CRS-HIPEC.

EP.TH.299Is peritoneal lavage with water the optimal washout as a preventative method for peritoneal disease following colorectal cancer resection? A systematic review

Aim To study available data on the advantages of peritoneal lavage with distilled water following colorectal cancer resection in improving overall patient outcomes Methods PubMed, Google Scholar, and Cochrane databases were searched until October 2020. References from relevant articles were reviewed to widen the search. Results Overall, 3 experimental studies were identified. Water was found to be superior to other peritoneal lavage solutions in inducing tumorigenic cell lysis in vitro. Mice who underwent peritoneal lavage with water survived longer and had a significantly reduced peritoneal tumour burden compared to mice who did not undergo lavage or those treated with saline lavage solution. Peritoneal secretions were found to contaminate water lavage and reduce its cell-lytic effect. Nonetheless, complete cell lysis was achieved, in vivo, by prolonging the time of cell exposure to contaminated lavage solution by 20 min. Conclusion Single peritoneal lavage with water is probably safe and may have a positive influence on patient outcomes. Further evidence is required to regard sequential peritoneal lavages with water as beneficial and safe in humans.

EP.FRI.247 Incidence and diversity of the primary appendiceal tumours in patients presenting with acute appendicitis: Our Experience

Background Primary appendiceal tumours are rare. Our experience with the incidental primary appendiceal tumours and their histological diversity. Patients and Method Operative and pathological databases of appendicectomies for presumed diagnosis of acute appendicitis between January 2015 and December 2020 were interrogated. Clinicopathological data were collected and analysed to present the incidence of primary appendiceal tumours, histopathological diversity and outcomes. Results 1908 appendicectomies were performed over the study period. 22 patients with primary appendiceal tumours (incidence rate 1.2%) had a mean age of 45.6(15-97) years and M:F ratio of 1:1.2. Only six patients (27.3%) had appendiceal tumour suspected either before or during surgery. 91% of the patients underwent laparoscopic appendicectomy. Right hemicolectomy was performed as the first intervention and further surgical procedure in 1 and 5 patients respectively. Histological tumour types included carcinoid(10), adenocarcinoma(4), low grade appendiceal mucinous neoplasm(4) mucinous adenocarcinoma & carcinoid(1), goblet cell carcinoid(2) and dysplastic serrated polyp(1). Tumours were located at the tip(10), body(10) and base(2). Median tumour size was 13(2.0-55.0) mm. Median hospital stay was 1.5(0-25) days. The mean survival was 30.9(2.80-73.70) months. Disease related death was a 97-year-old lady with a T4 adenocarcinoma and peritoneal disease who stayed for 25 days and offered palliative supports post appendicectomy. Conclusion Primary appendiceal tumours are diverse in histological types and are of varying prognosis. Appendicectomy alone seemed to be adequate in most cases with early-stage disease. Further surgery such as right hemicolectomy was required for adenocarcinoma and other high-grade tumours.

Primary Abdominal Cocoon with Right Intra-Abdominal Cryptorchidism: A Case Report

Background: Primary abdominal cocoon is a special peritoneal disease and easily cause misdiagnosis and mistreatment. Few cases have been reported primary abdominal cocoon with intra-abdominal cryptorchidism in the literature.Case presentation: We admitted one case of a 41-year-old male patient with primary abdominal cocoon and right intra-abdominal cryptorchidism. The main symptom of this patient was intermittent abdominal pain for more than one month, preoperative CT results showed that part of the small intestine folded into a mass, which was suspected of abdominal cocoon. Part of the small intestine was wrapped by fibrous membrane and the right testicle were observed in the abdominal cavity during the operation. Intestinal adhesion release and right cryptorchidectomy were performed successfully. Pathological results revealed that the membranous material was fibrous connective tissue with chronic inflammatory cell infiltration and no spermatogenic cells and sperm were observed in the seminiferous tubules of the testicular tissue. Conclusion: This article reports one case of primary abdominal cocoon with right intra-abdominal cryptorchidism. Primary abdominal cocoon lacks specific clinical manifestations, part of patients may have cryptorchidism and the diagnosis is difficult. We should improve the understanding of primary abdominal cocoon to better save the life of patient.