Adding diagnostic laparoscopy to computed tomography for the evaluation of peritoneal metastases in patients with colorectal cancer: a retrospective cohort study

Abstract Background Despite its widespread use, computed tomography (CT) is not perfect for evaluating peritoneal metastases of colorectal origin before cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS + HIPEC). We therefore evaluated the value of adding diagnostic laparoscopy to CT when assessing patient eligibility for CRS + HIPEC. Methods This was a retrospective study of a consecutive series of 112 patients evaluated systematically by diagnostic laparoscopy and CT between January 2012 and January 2018. Patient eligibility for CRS + HIPEC was assessed by the peritoneal cancer index (PCI) both at the time of initial diagnostic laparoscopy and during the retrospective review of CT images. Two experienced radiologists who were blinded to the PCI result at laparoscopy then independently estimated the PCI based on CT imaging. The primary outcome was the number of patients eligible for CRS + HIPEC by each method. Results We identified 112 patients, of whom 95 (85%) were eligible for CRS + HIPEC based on diagnostic laparoscopy and 84 underwent CRS + HIPEC. Overall, 14 patients (17%) experienced an “open-and-close” procedure. In contrast to diagnostic laparoscopy, 100 patients (89%) were identified as being eligible for CRS + HIPEC by CT (p = 0.13), which would have resulted in an additional five open-and-close procedures. Conclusions Adding diagnostic laparoscopy to CT produced a clinically relevant, but statistically non-significant, reduction in the number of patients eligible for CRS + HIPEC. We conclude that diagnostic laparoscopy may be of use in preoperative assessments when systematic analysis by CT scores the PCI as greater than ten. Future research should focus on the cost-effectiveness of this approach.