18F-FDG-PET/CT to select patients with peritoneal carcinomatosis for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy

115 Objectives Cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy (HIPEC) is associated with significantly longer survival in patients with peritoneal carcinomatosis (PC). No morphological imaging method has proven to accurately assess the tumor spread preoperatively for adequate patient selection. Aim of our study was to predict tumor load in patients with PC using FDG-PET/CT and to compare the results with those of PET and CT alone by correlating imaging findings with intraoperative staging. Methods 22 patients with PC from gastrointestinal (N=13) and ovarian cancer (N=8) and mesothelioma (N=1) underwent contrast-enhanced (ce) 18F-FDG-PET/CT before surgery and HIPEC. In a retrospective analysis PET, CT and fused PET/CT were separately and blindly reviewed for the extent of PC using the Peritoneal Cancer Index (PCI). Imaging results were correlated with the intraoperative PCI using Pearson’s correlation coefficient and linear regression analysis. Results There was a strong correlation between the PCI obtained with PET/CT and the surgical PCI with respect to the total score (r=0.951) as well as in the regional analysis (small bowel, r= 0.838; other, r=0.703). The correlation was slightly lower for CT alone (total score, r=0.919; small bowel, r=0.754; other, r=0.666) and significantly lower (p=0.002) for PET alone (total score, r=0.793; small bowel, r=0.553, other, 0.507). Conclusions Ce CT is superior to PET alone to predict the extent of PC. According to our results, the combination of both modalities (ce PET/CT) yielded the best results and proved to be a useful tool for selecting candidates for peritonectomy and HIPEC.