Plasma 5hmC Signatures as a Marker of Colorectal / Appendiceal Peritoneal Metastasis

Patients with peritoneal metastasis of colorectal or high grade appendiceal origin who are candidates for cytoreductive surgery with HIPEC (hyperthermic intraperitoneal chemotherapy) will be enrolled in this study. Blood collection for measurements of plasma cell-free DNA hydroxymethylation signatures will be performed at different time points, before and after surgery, in order to determine if plasma hydroxymethylation signatures are more sensitive than conventional tumor markers in identifying clinically detectable recurrence at 1 year after surgery.