Prognostic factors for peritoneal carcinomatosis originating from colorectal cancer: An analysis of 921 patients from a multi-institutional database

Purpose: The purpose of this study was to clarify the factors affecting R0 resection and the prognosis of patients with peritoneal carcinomatosis (PC) from colorectal cancer (CRC) in the Japanese population. Methods: A multi-institutional retrospective analysis of 921 patients who underwent surgery between 1991 and 2007 for CRC with PC was conducted. Clinicopathological variables were analyzed for prognostic significance. A multivariate analysis using a Cox regression modeling was performed to assess the prognostic value of the variables. Results: The median survival time of all patients was 14.3 months (range 0-209 months) and the 5-year overall survival rate was 9.7 %. The multivariate analysis revealed that a lymph node status of pN0/1, the absence of blood-born metastasis, R0 resection and adjuvant chemotherapy favorably affected the survival. Furthermore, the completion of R0 resection was significantly affected by the preoperative serum CEA level, the presence of blood-born metastasis and the grade of PC. The 5-year overall survival and median survival time of the patients with four favorable prognostic factors, namely pN0/1, the absence of blood-born metastasis, R0 resection and adjuvant chemotherapy, were significantly better than those of the remaining patients (37.1 vs. 7.2 % and 37.0 vs. 13.3 months, respectively; p < 0.0001). Conclusions: Although few patients with PC from CRC survive for more than 5 years, performing R0 resection with curative intent in association with postoperative adjuvant chemotherapy should be considered in appropriately selected patients.