Prospective Randomized Trial Evaluating Mandatory Second Look Surgery With HIPEC and CRS vs. Standard of Care in Subjects at High Risk of Developing Colorectal Peritoneal Metastases

Background: * Survival rates for colorectal cancer depend on a number of factors, including the existence of tumors outside the colon and rectum. Patients who had tumors elsewhere in the abdomen (such as in the peritoneum or ovaries) when they were diagnosed, as well as patients who had bleeding or obstruction when they were diagnosed, have a high risk of cancer recurrence even after surgery or other treatment. * If additional tumors are discovered early and removed while they are still small (often before they can show up on scans), survival rates may improve. In addition, patients who receive a heated chemotherapy solution delivered directly to the abdomen often have better treatment outcomes regardless of whether additional tumors were found. Further research can help determine the usefulness of both of these treatments in improving the outcomes of patients with colorectal cancer. Objectives: \- To determine whether patients who have had surgery for colorectal cancer have improved outcomes after receiving additional surgery combined with direct chemotherapy, compared with those who receive the current standard of care. Eligibility: \- Individuals at least 18 years of age who have had surgery for colorectal cancer within the past 14 months, who are considered to be at high risk for cancer recurrence, and whose current imaging scans show no signs of additional tumors. Design: * Participants will be divided into two treatment groups: a surgery group and a standard of care group. * Participants who had surgery less than 11 months ago will be enrolled in a 3-month lead-in phase to receive standard follow-up care, including labs, scans, and physical examinations, before being randomized to a treatment group between 11 and 14 months after surgery. Participants who had surgery between 11 and 14 months ago will be randomized at the time of enrollment. * Participants in the surgery group will have the following procedures within 2 weeks of randomization: * Abdominal