Su1739 Risk Factors for Pulmonary Embolism Following Cytoreductive Surgery and Intraperitoneal Chemotherapy for Peritoneal Carcinomatosis

Introduction: Peritoneal carcinomatosis denotes extensive tumour involvement of the peritoneum, and is often regarded as terminal. There has been a paradigm shift in treatment, with the application of cytoreductive surgery combined with intra-peritoneal chemotherapy. The extensive nature of the surgery and malignancy-associated hypercoagulable state should increase the risk of PE, which can further increase morbidity and/or mortality. Incidence and risk factors for pulmonary embolism (PE) in this population have not been investigated in detail. Aims: To establish the incidence and specific operative risk factors for developing PE in patients with peritoneal carcinomatosis post peritonectomy and peri-operative intraperitoneal chemotherapy. Methods: A cohort of 596 patients that underwent cytoreductive surgery (peritonectomy) over a 12-year period was identified using the prospective database from St George Hospital Peritonectomy Unit. A case-control study was undertaken whereby cases were defined by the development of PE within 60 days of peritonectomy. A diagnosis of PE was based on computed tomography pulmonary angiography confirmation. The prospective database was reviewed to obtain the following clinical information for both cases (with PE) and controls (without PE): length of surgery, use of hyperthermic intraperitoneal chemotherapy (HIPEC) and early postoperative intraperitoneal chemotherapy (EPIC), peritoneal carcinomatosis index (PCI) and number of intraoperative blood transfusions. Results: The mean age of the cohort was 52.7 ± 13.1 years, with no significant difference in the ages of cases or controls; 43.3% were male and 56.7% were female. Primary malignancies in these patients were pseudomyxoma peritonei, appendiceal, ovarian or colorectal cancer, and mesothelioma. Out of the 596 patient cohort, 34 were identified as having PE post cytoreductive surgery (5.7%). When compared to controls, the PE group had longer mean operative time of 10.4 ± 2.8 hours vs 8.9 ± 3.1 hours (p=0.01) and higher mean PCI values at 23 ± 12 vs 18 ± 11 (p=0.02). An operative time of more >9 hours increased the risk of developing PE (OR 3.3, 95% CI 1.41-7.72, p=0.006) as did having a PCI of >20 (OR 2.4, 95% CI 1.18-4.9, p=0.02). There was no difference in mean transfusion requirements (6.6 vs 6.0; p=0.67). No significant association was found between HIPEC and development of PE (x2=2.87, 1 df, P=0.9) or EPIC and subsequent PE (x2=0.001, 1 df, P=1). Conclusions: There is a relatively high incidence of pulmonary embolism in patients following cytoreductive surgery for peritoneal carcinomatosis. Patients at highest risk of developing PE postoperatively are those with PCI of more than 20 and those who have operations lasting more than 9 hours. Peri-operative chemotherapy and blood transfusions are not risk factors for PE.