Peritoneal carcinomatosis arising from rectal or colonic adenocarcinoma treated with cytoreductive surgery (CRS) hyperthermic intraperitoneal chemotherapy (HIPEC): two different diseases.

PURPOSE: Peritoneal carcinomatosis (PC) from colorectal cancer (CRC) has poor survival. Multi-modal treatment including systemic chemotherapy, cytoreductive surgery (CRS), and hyperthermic intraperitoneal chemotherapy (HIPEC) can be used in selected patients with curative intent. The majority published works consider PC of CRC origin as a homogenous disease. Aim of this study is to stress the different biological behaviors and survival of PC according to colonic or rectal origin.

METHODS: Data of CRS and HIPEC procedures for PC of CRC origin performed at MD Anderson Cancer Center-Madrid (Spain) have been collected, dividing patients into two groups according to colonic or rectal PC. Clinical, operatory, and postoperatory variables of the two groups have been analyzed to compare survival-related rates and PC origin.

RESULTS: In the years 2004-2015, 114 procedures of CRS followed by HIPEC for peritoneal metastasis of different origin have been performed; of these, 36 procedures were for colorectal PC (31 patients in colonic and 5 in rectal group). Two groups are homogenous after analysis of clinical, operatory, and follow-up data. Median survival (OS) is significantly higher in colonic compared to rectal group (47.83 vs. 22.0 months, p 0.008). 3- and 5-year survival rate is 74 and 50% in colonic group vs. 20 and 0% in rectal group.

CONCLUSION: Rectal origin PC has a more aggressive behavior compared to colonic origin, reflecting in a worst prognosis of patients affected by rectal origin PC. According to our data and literature, indications of multi-modal treatment including CRS and HIPEC should be more restrictive for rectal cancer PC. Authors should differentiate colonic and rectal origin of PC when reporting cases in the literature.