Clinical Value of (18)F-FDG- PET-CT in the Preoperative Staging of Peritoneal Carcinomatosis from Colorectal Origin.

BACKGROUND: dequate staging is essential in patients with peritoneal carcinomatosis (PC) from colorectal cancer (CRC) who are candidates for cytoreductive surgery (CRS) followed by hyperthermic intraperitoneal chemotherapy (HIPEC). Metabolic imaging using (18)F-FDG-PET-CT is commonly used to exclude distant metastasis in these patients. Here, we aimed to assess the performance of (18)F-FDG-PET-CT in locoregional staging of the extent of PC.
METHODS: Patients with PC from CRC underwent staging including 18F-FDG-PET-CT. In the absence of systemic -dissemination, CRS and oxaliplatin based HIPEC were performed. The extent of PC was quantified during surgery using the modified 7 region count (7RC). The correlation between imaging based estimation of PC extent and surgical 7RC was analyzed using Pearson correlation using both patient based and region based analyses.
RESULTS: Fifty-five patients were included between February 2005 and October 2018. Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 57%, 98%, 95%, 78% and 82% respectively for non-mucinous tumors and 32%, 100%, 100%, 55% and 63% respectively. (18)F-FDG-PET-CT detected the presence of colorectal PC in 96% of patients suffering from PC with nonmucinous histology and in 60% of patients suffering from PC with mucinous histology. Correlation between imaging 7RC and surgical 7RC was better for PC with nonmucinous histology (r = 0.623) than for PC with mucinous histology (r = -0.180).
CONCLUSIONS: Despite of underestimating the exact extent of disease involvement, (18)F-FDG-PET-CT shows good performance in detecting colorectal PC with nonmucinous histology. For colorectal PC with mucinous histology, (18)F-FDG-PET-CT, however, shows poor performance. Since (18)F-FDG-PET-CT did not detect the presence of colorectal PC in all patients in whom long-term survival could be achieved, (18)F-FDG-PET-CT should be implemented into a broad pre-operative assessment strategy. Copyright© Acta Chirurgica Belgica.