To learn if circulating tumor DNA (ctDNA) testing before cytoreductive surgery (CRS) with or without heated intraperitoneal chemotherapy (HIPEC) can show if patients have a low or high risk of the disease returning and help doctors decide if less or more intense chemotherapy is needed as treatment before surgery. ctDNA testing measures the amount of tumor DNA (genetic information) in the blood.
Histologically/cytologically confirmed diagnosis of moderate or poorly differentiated appendiceal or colorectal adenocarcinoma of any grade with Initial resectable disease.
Have metastatic peritoneal disease that is visible on imaging or at the time of laparoscopy.
Age ≥18 years. Because no adverse event data are currently available on the use of ctDNA in chemotherapy decision making in patients <18 years of age, children are excluded from this study.
ECOG performance status ≤1 (Karnofsky ≥70%,).
Patients who have not recovered from adverse events due to prior anti-cancer therapy (i.e., have residual toxicities > Grade 1) with the exception of alopecia.
Patients who are receiving any other investigational agents.
Patients with brain or other visceral (i.e. liver and/or lung) metastases at the discretion of the investigator.
Patients with uncontrolled intercurrent illness (Indicate clearly what type or extent)