Background: Colorectal peritoneal carcinomatosis (CRPC) is a primary cause of death in colorectal cancer (CRC) patients. In the past, computed tomography (CT) has been the primary method used to evaluate the distribution of CRPC. This study uses 18F-FDG positron emission tomography/computed tomography (PET/CT) to investigate the distribution characteristics of CRPC. Materials and Methods: The distribution characteristics of 46 patients with CRC who were treated in the authors' hospital were retrospectively analyzed using the peritoneal cancer index (PCI). Results: The 46 patients in the study showed CRPC involvement in 203 of the 598 abdominal and pelvic regions studied (33.9%, 203/598). The regional proportions of CRPC involvement, from high to low, were as follows: region 6 (13.8%), region 0 (10.3%), region 1 (9.9%), region 5 (8.9%), region 7 (8.4%), region 3 (8.4%), region 2 (7.4%), region 4 (7.4%), region 11 (6.9%), region 8 (6.4%), region 12 (5.4%), region 9 (3.4%), and region 10 (3.4%). Thirty-three patients had a PCI of <20, and 13 patients had a PCI of ≥20. Those 13 were among the 17 (37% 17/46) who had CRPC involvement in all three regions. According to the location of the primary CRC focus, the 46 patients were divided into three groups: right hemicolon, left hemicolon, and rectum. The frequency of CRPC was greater in the rectum group than in the left hemicolon group, and the SUVmax of CRPC was greater in the right hemicolon group than in the left hemicolon group; these differences were statistically significant (p < 0.05). Conclusions: The distribution of CRPC has certain characteristics in the abdominal and pelvic cavities. The PET-PCI scores can provide a basis for the diagnosis and clinical treatment strategies in patients with CRC.
Keywords: 18F-fluorodeoxyglucose; colorectal cancer; peritoneal cancer index; peritoneal carcinomatosis; positron emission tomography/computed tomography (PET/CT).