The purpose of this study is to determine if Near-Infrared fluorescence imaging is an effective approach to detect the colorectal tumoral tissues and peritoneal implants in colorectal cancer patients.

Primary objective

Evaluation of the ability of NIR imaging using ICG to demonstrate (the gross tumoral mass and/or) peritoneal metastatic " implants " in patients operated for peritoneal carcinomatosis from colorectal carcinoma

Secondary objective:

Definition of the histological distribution (in the vessels, in the extravascular spaces, in specific cells) of IV injected ICG in the normal and pathological tissues (and, if any is demonstrated per-operatively, a) in the nodes of these patients found fluorescent and removed and/or b) at the level of the fluorescent foci observed at the level of the hepatic surfaces)

Methodology:

The day before the operation:

ICG 0.125 mg/kg will be given as an iv injection the day before the operation.

In the operating room:

When the patient will be operated, the surgeons will (under "conventional" video control) search and establish as usual the presence (of "gross" tumoral mass and) of metastatic deposits at the level of the peritoneal surfaces. NIR imaging will be acquired during these manoeuvers and, if detected, fluorescent structures and/or foci will be anatomically defined by the surgeons.

If ("gross" tumoral mass and/or) metastatic deposits are seen fluorescent, the operation will be then continued as usual but each anatomical piece will be controlled "ex vivo" for its fluorescent character or not. All fluorescent foci on these anatomical pieces will be identified as such by a mark and/or by a "suture".

If ("gross" tumoral mass and/or) metastatic deposits are not seen fluorescent, ICG 0.125 mg/kg will be given as an iv injection and the vascularization, income of the ICG in the tumoral implants (judged by the surgeon the most representative of the patient's status) will be dynamically studied using the PDE camera during the 10 minutes following the IV injection.

If no hepatic metastases were pre-operatively documented, the surface of the liver will be controlled and, if superficial fluorescent foci are observed, these will be biopsied.

In the Laboratory of Pathology:

The tumoral tissues as well as -if identified- the "non identified as tumoral" fluorescent tissular foci will be processed as usual.

All the slides obtained will be analyzed using the near-infrared fluorescence microscope for the presence or the absence of (detectable) ICG and the different ICG-positive compartments (vascular spaces, interstitial spaces, normal and/or tumoral cells, macrophages,…) will be determined.

Inclusion Criteria:

• Patients (either newly diagnosed, or relapsing) with peritoneal carcinomatosis from histo-pathologically proven colorectal carcinoma who are candidate for "open" surgery,
• Informed consent form signed.

Exclusion Criteria:

• Age less than18 years old.
• Inability to give informed consent.
• History of allergy or hypersensitivity against the investigational product (its active substance or ingredients), to iodine or to shellfish.
• Apparent hyperthyroidism, autonomous thyroid adenoma, unifocal, multifocal or disseminated autonomy of the thyroid gland.
• Documented coronary disease.
• Advanced renal impairment (creatinine > 1,5mg/dl).
• During the 2 weeks before the enrolment, concurrent medication which reduces or increases the extinction of ICG (i.e. anticonvulsants, haloperidol and Heparin).
• Pregnancy, breastfeeding