Sentinel lymph node biopsy in colorectal cancer: a pilot study.

BACKGROUND Although sentinel lymph node biopsy technique is the gold standard in the management of malignant melanoma and is gradually replacing conventional axillary dissection in breast cancer, its use in colorectal cancer is still controversial. The objective of this study is to demonstrate the feasibility and safety of sentinel node biopsy in the management of colorectal carcinoma. METHODS Consecutive patients with colorectal carcinoma without preoperative evidence of nodal or distant metastatic disease were included. Intraoperative subserosal injection of 1 mL of isosulfan blue (Lymphazurin) was performed around the tumor in cases of colon cancer and ex-vivo infiltration was used for rectal cancer after resection was completed. Blue stained nodes were dissected and submitted for routine pathology exam. If nodes were deemed negative for neoplasm, immunohistochemistry for cytokeratin was performed. The specimen and non-stained nodes were resected and processed in the usual fashion. Sensitivity and negative predictive value were calculated and adverse effects to the blue dye were registered. RESULTS Ten patients were included with at least one sentinel lymph node identified in each. Mean number of sentinel and non-sentinel lymph nodes were 2.5 and 15.6 per patient, respectively. The sensitivity and negative predictive value of the sentinel node after immunohistochemistry were both 100%. There were no adverse effects caused by the dye. CONCLUSIONS Sentinel lymph node biopsy technique in colorectal cancer is feasible, has a high diagnostic accuracy and is harmless.