ICG in Colon Cancer

Adequate lymphadenectomy is a key component of curative colon cancer surgery because lymph node status is essential for accurate staging and postoperative treatment planning. Indocyanine green (ICG) fluorescence imaging has become increasingly used intraoperatively to make otherwise invisible lymphatic pathways visible in real time.

Preoperative and Perioperative Care:

All patients will undergo standard preoperative evaluation including colonoscopy with biopsy confirmation, baseline laboratory investigations, carcinoembryonic antigen measurement, and contrast-enhanced CT staging. Perioperative care will follow an enhanced recovery pathway including counseling, thromboembolism prophylaxis, antibiotic prophylaxis, multimodal analgesia, early mobilization, and early oral intake.

Operative Protocol:

Laparoscopic oncologic colectomy will be performed according to tumor location. Fluorescence imaging will be performed using the KARL STORZ IMAGE1 STM Rubina platform. Indocyanine green will be injected subserosally around the tumor in four quadrants whenever feasible. Near-infrared imaging will then be used to identify lymphatic channels and nodal basins before definitive mesenteric division. Any fluorescence-related modification of the extent of mesenteric excision or pedicle clearance will be recorded prospectively. Before bowel anastomosis, intravenous indocyanine green will be used to assess perfusion of the bowel ends by near-infrared fluorescence imaging.

Pathology and Follow-up:

The mapped area will be identified on the specimen by sutures or clips or separately labeled packets, allowing the pathologist to record metastatic lymph nodes as located within or outside the ICG-mapped basin. Patients will be followed during hospital admission and for 3, 6, and 9 months after surgery to record postoperative complications, final histopathological outcomes, and morbidity according to the Clavien-Dindo classification

• Indocyanine green (ICG) injection for intraoperative lymph node imaging (Drug): Indocyanine green is injected subserosally around the tumor in four quadrants for lymphatic mapping. Additionally, intravenous ICG is administered before bowel anastomosis to assess perfusion of the bowel ends using near-infrared fluorescence imaging.
• Laparoscopic Colon Cancer Resection (Procedure): Standard laparoscopic colectomy with oncologic lymphadenectomy performed according to institutional practice.

Primary outcomes

• Proportion of analyzable pN+ patients with all metastatic lymph nodes located within the ICG-mapped lymphatic basin [Up to 2 weeks postoperatively (upon completion of final histopathology report)]: This outcome evaluates the accuracy of ICG mapping. It is measured as the proportion of analyzable pN+ patients in whom all metastatic lymph nodes identified on final histopathology are located within the ICG-mapped lymphatic basin.

Secondary outcomes

• Successful intraoperative visualization of lymphatic drainage (Feasibility rate) [Intraoperative]: The rate of successful intraoperative visualization of lymphatic channels and nodal basins after subserosal ICG injection.
• Frequency of fluorescence-guided modification of mesenteric excision [Intraoperative]: The frequency at which ICG mapping prompts a modification in the extent of mesenteric excision or pedicle clearance.
• Change in the planned transection line due to perfusion assessment [Intraoperative]: The proportion of cases in which intravenous ICG perfusion assessment leads to a change in the planned bowel transection line.
• Metastatic lymph nodes identified outside conventional resection margins [Up to 2 weeks postoperatively (upon completion of final histopathology report)]: The frequency of identifying metastatic lymph nodes located outside the predefined conventional resection margins using ICG guidance.
• Total Lymph nodal yield [Up to 2 weeks postoperatively (upon completion of final histopathology report)]: The total number of lymph nodes retrieved per patient as determined by final histopathological assessment.
• Postoperative Morbidity and Mortality [Baseline, postoperative day 30, and at 3, 6, and 9 months after surgery]: The incidence of postoperative complications (graded according to the Clavien-Dindo classification), readmission, reoperation, and mortality rates.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

Age >= 18 years.

\- Histologically confirmed colon adenocarcinoma.

Exclusion Criteria:

* Emergency surgery (obstruction/perforation with sepsis) requiring urgent operation.
* Known allergy or contraindication to ICG (including prior anaphylaxis to ICG; severe hypersensitivity history per anesthesia assessment).
* Pregnancy or breastfeeding.
* Severe hepatic failure (because ICG clearance is hepatobiliary) or other contraindication determined by anesthesia team.
* Planned palliative resection only.
* ASA physical status IV or patients otherwise deemed unfit for elective curative colectomy.

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