Background: Peritoneal metastases (PM) will be unexpectedly present in approximately 10% of colorectal cancer patients having primary cancer resection. In the past this was considered to be an incurable condition with a terminal outcome. In patients determined to have peritoneal dissemination at the time of resection, the intervention was considered palliative. Recently, long term benefit from definitive treatment of PM with cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) has become a reality. These treatments are now appropriate for primary appendiceal and colorectal cancer determined to have PM at the time of resection.