Immunoguided lymph node dissection in colorectal cancer: a new challenge?

Area of Science:

• Oncology
• Surgical Technology
• Nuclear Medicine

Background:

• Accurate staging of colorectal cancer, particularly lymphatic involvement, is crucial for surgical planning and postoperative management.
• Recurrent colorectal cancer presents unique challenges in identifying all tumor sites.
• Radioimmunoguided Surgery (RIGS) offers a potential method for enhanced tumor localization.

Purpose of the Study:

• To evaluate the efficacy of RIGS technology in detecting occult tumor sites in patients with recurrent colorectal cancer.
• To assess the impact of RIGS on surgical decision-making and postoperative therapy planning.
• To compare the performance of RIGS in lymphatic versus non-lymphatic tissues.

Main Methods:

• Fifty-eight patients with recurrent colorectal cancer underwent surgery using RIGS.
• Patients received an injection of iodine-125 labeled monoclonal antibody (MoAb) CC49 (anti-TAG-72).
• Surgical exploration was augmented by a gamma-detecting probe for RIGS-guided localization, with pathological confirmation of detected sites.

Main Results:

• RIGS detected 177 suspected tumor sites compared to 117 by traditional exploration in 58 patients.
• Occult tumor sites identified by RIGS were pathologically confirmed in 27.5% of patients, leading to 16 major surgical plan changes.
• RIGS demonstrated high positive predictive value (95.6%) and negative predictive value (90%) in non-lymphoid tissue, but varied in lymphoid tissue (PPV 40%, NPV 100%).

Conclusions:

• RIGS technology significantly enhances the detection of tumor sites in recurrent colorectal cancer.
• RIGS findings, especially when combined with pathological confirmation for lymph nodes, aid surgeons in making informed intraoperative decisions.
• The application of RIGS can lead to critical modifications in surgical strategy and postoperative treatment planning.