Predicting the survival of patients with peritoneal carcinomatosis of colorectal origin treated by aggressive cytoreduction and hyperthermic intraperitoneal chemotherapy

Background: Peritoneal carcinomatosis in the absence of distant metastasis occurs in approximately 8 per cent of patients with colorectal cancer. Cytoreduction followed by hyperthermic intraperitoneal chemotherapy (HIPEC) is a new treatment option. Patient selection is crucial to outcome. Methods: Cytoreduction followed by HIPEC was performed in 102 patients with peritoneal carcinomatosis. The following factors were studied for association with survival: perforation and obstruction of the primary lesion, location of the primary lesion, obstruction associated with carcinomatosis, presentation, tumour differentiation and histological type. Extent of disease and completeness of cytoreduction were also studied. Hazard ratios (HRs) were used to study these factors. Results: Location of the primary tumour in rectum (HR 3.14 (95 per cent confidence interval (c.i.) 1.11 to 8.91); P = 0.069), poor differentiation (HR 1.73 (95 per cent c.i. 1.04 to 2.88); P = 0.031) and signet cell histological type (HR 2.24 (95 per cent c.i. 1.21 to 4.16); P = 0.008) were associated with shorter survival. Important factors predicting survival were the number of affected regions (HR 1.38 (95 per cent c.i. 1.20 to 1.59); P < 0.001), the simplified peritoneal cancer score (HR 1.19 (95 percent c.i. 1.12 to 1.26); P < 0.001) and completeness of cytoreduction (HR 8.54 (95 per cent c.i. 4.01 to 18.18); P < 0.001). No other factor correlated with survival. Conclusion: The survival of patients with peritoneal carcinomatosis of colorectal origin is dominated by the extent of disease and the amount of residual tumour after cytoreduction.