Preoperative assessment of peritoneal carcinomatosis of colorectal origin.

The goal of preoperative assessment of patients with peritoneal carcinomatosis (PC) from colorectal origin is to select candidates for curative surgery by evaluating the possibility of complete resection, and to plan the surgical procedure. Quantitative and qualitative evaluation of lesional localization remains difficult even with current technical progress in imaging. Computed tomography (CT), the reference imaging technique, allows detection of both peritoneal and extra-peritoneal lesions. Sensitivity and specificity for detecting PC are 83% (95%CI: 79-86%) and 86% (95%CI: 82-89%), respectively. Functional imaging, with diffusion-weighted magnetic resonance imaging (MRI) and positron emission tomography PET-CT allows efficient exploration of peritoneal lesions. MRI is operator-dependent, with a long learning curve, and is, at present, essentially used only in expert centers. A standardized protocol provided by the radiologists working with the French National Center for rare peritoneal tumors RENA-RAD (https://www.renape-online.fr/fr/espace-professionnel/rena-rad.html) is however available on line. PET-CT is particularly useful for identifying and defining extra-peritoneal disease. Combining imaging techniques, particular CT with MRI, seems to improve the calculation of the Peritoneal Cancer Index compared to CT alone. Surgical exploration is the reference technique to evaluate PC. Currently, the literature cannot confirm whether laparoscopy performs as well as laparotomy, but laparoscopy is, de facto, the fundamental tool to decrease the number of unnecessary laparotomies in these patients. To optimize the pre-, intra- and postoperative reporting of the extent of PC, the French National Network for management of PC (RENAPE and BIG-RENAPE: https://www.e-promise.org/) has offered on-line a free-of-charge, standardized, multidisciplinary and transversal software.