eP667 - Presentation and Operability of Peritoneal Malignancy in a Colorectal MDT - A Five-Year Analysis

Purpose/Background: The patterns of presentation and operability of peritoneal malignancy of colorectal origin in developing countries are not well documented. To address this, we conducted a study to identify the spectrum of peritoneal disease discussed at a colorectal multidisciplinary tumour board and determine presenting patterns and operability at diagnosis.Methods/Interventions: This study was conducted in the colorectal unit of a tertiary care teaching hospital in South India. We included all consecutive patients suspected to have peritoneal disease and discussed in the colorectal MDT between January 2018 and December 2022. We collected data from a prospectively maintained database and electronic hospital records.Results/Outcomes: During the study period, 240 patients with suspected peritoneal malignancy were discussed in the MDT. Of these, 126 (52.5%) were male, and the mean age at presentation was 46.4 years (SD13.8, Range 7 to 78). Among the patients with suspected peritoneal malignancy, 159 (66.2%) presented with colorectal peritoneal metastasis (CPM), 38 (15.8%) with pseudomyxoma peritonei, and 15 (6.3%) with mesothelioma. Sixteen patients were diagnosed with peritoneal metastasis from primary ovarian/gall bladder/stomach malignancy, and twelve had alternative pathology. Of the 159 patients with CPM, 105 (66%) had peritoneal disease at initial presentation, 39 (24.5%) presented with peritoneal recurrence after treatment completion, and 15 (9.4%) had progression to peritoneal metastasis during neoadjuvant therapy. Only 16 (10.1%) patients were candidates for upfront cytoreductive surgery(CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC).In contrast, 55.3% (21/38) of patients with pseudomyxoma peritonei and 53.3% (8/15) of patients with mesothelioma were resectable at presentation.Conclusion/

Discussion: Colorectal peritoneal metastasis accounts for about two-thirds of peritoneal disease referrals at a tertiary care centre. Two-thirds of CPM cases present synchronously with the primary tumour, and only 10% are candidates for upfront surgery. In contrast, about half of pseudomyxoma peritonei and mesotheliomas are suitable for upfront CRS and HIPEC.