Role of MDCT for selection of peritoneal carcinomatosis patients as candidates for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy: Concordance between radiological and surgical scores using the Peritoneal Cancer Index

Objective

To evaluate the accuracy of multidetector computed tomography (MDCT) to select patients with peritoneal carcinomatosis (PC) as candidates for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS + HIPEC), through an analysis of the degree of correlation between the radiological (rPCI) and surgical (sPCI) scores in the PC index.

Methods

Observational, retrospective, single-centre study between 1 May 2014 and 31 May 2018. Calculated rPCI assessed by MDCT was compared with the sPCI using the Concordance Correlation Coefficient (CCC). The Bland-Altman method was used to plot the difference between the two observations against their mean with a confidence interval (CI) of 95%. We assessed whether tumour volume affects the CCC by setting a cut-off point of sPCI at 15 and considering a sensitivity and specificity of rPCI > 20 as a predictor of unresectability.

Results

50 patients underwent surgery. Mean sPCI was 11.8 (9.5) and rPCI was 11.0 (10.2), with a CCC of 0.94 (95% CI: 0.91–0.97). The CCC in the 35 patients with sPCI 20 had a sensitivity of 0.82 (95% CI: 0.68–0.92) and a specificity of 0.40 (95% CI: 0.05–0.85). The positive predictive value was 0.92 (95% CI: 0.80–0.98), while the negative predictive value was 0.20 (95% CI: 0.03–0.56).

Conclusion

MDCT, interpreted by an expert radiologist, is reliable for the selection of patients as candidates for CRS + HIPEC; however, the rPCI value cannot be considered in isolation as a contraindication to full treatment. Greater tumour volume usually leads to a worse concordance between rPCI and sPCI.