The prognostic impact of surgical staging procedures in patients with colorectal and appendiceal peritoneal metastases undergoing CRS-HIPEC

Abstract Background Surgical staging procedures are used to select patients with peritoneal metastases for surgery. We aimed to evaluate the prognostic impact of surgical staging procedures and the proportion of abdominal wall metastases in patients with peritoneal metastases scheduled for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). Methods Data were collected from a prospective maintained HIPEC register 2012 to December 2019. Patients with peritoneal metastases originating from colorectal or appendiceal adenocarcinomas were included. Information about surgical staging procedures was registered. Results were then compared with those registered at definite CRS-HIPEC surgery and survival was analysed in relation to surgical staging procedures. Results In total, 167 patients were included, of whom 45 had undergone a surgical staging procedure before CRS-HIPEC. Median overall survival in the surgical staging group was 1.89 years and in the non-staging group 3.19 years (p = 0.01). In the surgical staging group, eleven patients developed abdominal wall metastases (24%) compared with four (3%) in the non-staged group (p < 0.001). Fifteen staged patients (33%) were considered inoperable at definite surgery (open-close). PCI score (p < 0.001) was higher at definite surgery in patients who had undergone a staging procedure. Factors associated with shorter overall survival in univariate analysis were: a separate surgical staging procedure prior to CRS-HIPEC, PCI ≥ 21 and presence of signet ring cells. However, a staging procedure was not associated with a shorter overall survival in multivariate analysis. Conclusion Surgical staging procedures are associated with a risk of inoperability and development of abdominal wall metastases. The use of a separate surgical procedure for staging patients before CRS-HIPEC should be selective.