Ultrastaging of Early Cancer of the Large Bowel Using Intraoperative Lymphatic Mapping, Sentinel Node Analysis and Blood Testing

OBJECTIVES:

• To determine the accuracy and sensitivity of intraoperative lymph node mapping with isosulfan blue and sentinal node biopsy (SLN) in patients with colorectal cancer (CRC).
• To compare molecular and immunohistochemical methods for detection of micrometastases in the SLN and primary tumor and evaluate the clinical outcome.
• To evaluate the clinicopathological utility of hematogenous micrometastases in predicting disease recurrence in CRC.

OUTLINE: Patients receive isosulfan blue subserosally around the primary tumor for sentinel lymph node (SLN) identification and SLN(s) are marked. Patients undergo a standard colon resection as planned to include the SLN(s) and regional lymph nodes.

Lymph nodes removed during surgery are analyzed within 30 days after surgery. Routine pathologic analysis (H&E) are performed on all lymph nodes (SLN and non-SLN) removed. Immunohistochemical (IHC) staining for cytokeratin antibodies AE-1/AE-3 or MAK-6 are performed on all lymph nodes negative by H&E. Multimarker PCR (MM PCR) are performed on all SLNs. Blood samples are collected at baseline and then periodically for 4 years for MM PCR to detect circulating tumor cells and standard tumor markers (e.g., CEA).

After surgery, patients are followed every 6 months for 4 years.