Background: The sentinel lymph node (SLN) mapping technique has been used i
n breast cancer and melanoma, and was recently described for colon cancer.
Methods: Thirty-five patients with colon cancer underwent intraoperative SL
N mapping. One milliliter of 1% isosulfan blue was injected subserosally ar
ound the tumor. The first nodal area that was highlighted with blue was ide
ntified as the SLN. All lymph nodes underwent examination with hematoxylin
and eosin (H&E) stain. SLNs underwent additional sectioning and were staine
d with CAM 5.2.
Results: Lymphatic mapping adequately identified the SLN in 25 patients (71
%). In the 15 cases where the SLNs were negative for metastases, all other
non-SLNs were also negative (0% false negative rate). The SLN was the only
site of metastases in 6 (17%) of 35 patients. CAM 5.2 staining provided the
only evidence of micrometastases in 4 (11%) of 35 patients.
Conclusions: Intraoperative SLN mapping is a feasible technique with a reas
onable SLN identification rate (71%). The absence of metastases in the SLNs
accurately predicts the status of the non-SLNs. Tumors in 11% of patients
were upstaged by the demonstration of micrometastatic involvement, and thes
e patients may benefit from further adjuvant chemotherapy. (C) 2001 Excerpt
a Medica, Inc. All rights reserved.