Multi-modality Imaging in Peritoneal Carcinomatosis of Colorectal Origin

In oncologic surgery complete tumor resection is important for treatment outcome and patient survival. When performing cytoreductive surgery (CRS) for peritoneal carcinomatosis of colorectal origin it can sometimes be difficult to distinguish tumor deposits from adhesions and scar tissue. Intraoperative tumor localization and resection can be enhanced using intraoperative imaging techniques (e.g. targeted radioguided or fluorescence guided surgery). A powerful synergy can be achieved by combining radiotracers (e.g. Indium-111) and optical tracers (e.g. IRDye 800CW) conjugated to an antibody against a tumor-associated antigen. Labetuzumab specifically recognises CEA which is expressed on \> 95% of all colorectal cancers. Therefore Indium-111-DOTA-labetuzumab-IRDye800CW is a perfect dual-labeled antibody for dual-modality image-guided surgery in peritoneal carcinomatosis of colorectal origin. The concept has been shown in preclinical studies with mice and the investigators will translate this to the clinic. Eligible patients with peritoneal carcinomatosis of colorectal origin scheduled for CRS + HIPEC will receive dual-labeled labetuzumab 6-7 days before surgery. At day 4 or 5 a SPECT/CT of the abdomen and thorax will be obtained. Cytoreductive surgery at day 7 will be extended with the use of a near-infrared fluorescence camera and a gamma probe. The aim of this study is to assess the feasibility and safety of intraoperative dual-modality imaging with Indium-111-DOTA-labetuzumab-IRDye800CW in peritoneal carcinomatosis of colorectal cancer.