The initial route of
metastases in most patients with
melanoma is via the lymphatics to the regional nodes. However, routine
lymphadenectomy for patients with clinical stage I
melanoma remains controversial because most of these patients do not have nodal
metastases, are unlikely to benefit from the operation, and may suffer troublesome postoperative
edema of the limbs. A new procedure was developed using vital
dyes that permits intraoperative identification of the sentinel lymph node, the lymph node nearest the site of the primary
melanoma, on the direct drainage pathway. The most likely site of early
metastases, the sentinel node can be removed for immediate intraoperative study to identify clinically occult
melanoma cells. We successfully identified the sentinel node(s) in 194 of 237 lymphatic basins and detected
metastases in 40 specimens (21%) on examination of routine
hematoxylin-
eosin-stained slides (12%) or exclusively in immunohistochemically stained preparations (9%).
Metastases were present in 47 (18%) of 259 sentinel nodes, while nonsentinel nodes were the sole site of
metastasis in only two of 3079 nodes from 194
lymphadenectomy specimens that had an identifiable sentinel node, a false-negative rate of less than 1%. Thus, this technique identifies, with a high degree of accuracy, patients with early stage
melanoma who have nodal
metastases and are likely to benefit from radical
lymphadenectomy.