Richard Essner, MD, FACS

The surgical management of cutaneousmelanoma remainscontroversial in part becausethere is no consensus regarding themargins of excision for the primarytumor or the therapeutic benefit ofremoving clinically normal appearingregional lymph nodes (electivelymph node dissection).[1] Intraoperativelymphatic mapping with sentinellymph node dissection hasrevolutionized the management of regionallymph nodes by allowing thesurgeon to perform a minimally invasiveprocedure instead of electivelymph node dissection, and by allowingthe pathologist to focus on one ortwo lymph nodes rather than all thenodes in a complete lymph node dissectionspecimen.[2]

Intraoperative lymphatic mapping and sentinel lymphadenectomy has become an increasingly popular technique for staging the regional lymph nodes in early-stage melanoma. This operative technique allows for detailed pathologic analysis of the first (or sentinel) lymph node in direct connection with the primary tumor, and provides a unique opportunity for assessing potential immunologic interactions between the primary tumor and regional lymph node basin. We performed lymphatic mapping and sentinel lymphadenectomy on 25 patients with early-stage melanoma and resected an additional nonsentinel node in each case. Sentinel and nonsentinel nodes were evaluated by routine pathologic analysis. A portion of each node was processed for expression of the dendritic markers of activation CD80, CD86, and CD40, and their corresponding T-cell receptors CTLA-4 and CD28. Of 25 patients undergoing lymphatic mapping and sentinel lymphadenectomy, 20 (80%) had matched sentinel and nonsentinel nodes. A total of 26 matched lymph node sets were obtained: three pairs from one patient and two from an additional two patients. Reverse transcription polymerase chain reaction analyses of corresponding sections of the sentinel and nonsentinel nodes demonstrated a marked reduction in semiquantitative expression of CD80 (77%), CD86 (77%), and CD40 (85%), as well as CTLA-4 (88%) and CD28 (85%) in sentinel as compared to nonsentinel nodes. The diminished expression of the dendritic cell markers appeared to be unrelated to the B-cell (CD20) and T-cell (CD2) expression. Lymphatic mapping and sentinel lymphadenectomy allows for detailed pathologic and molecular characterization of sentinel nodes. Our results suggest a quantitative reduction in dendritic cell markers in sentinel as compared to nonsentinel nodes, which may be important in the immunologic interaction between the primary site and regional lymph node basin and may also serve as useful criteria for identifying sentinel nodes. [ONCOLOGY 16(Suppl 1):27-31, 2002]

The role of elective lymph node dissection in the treatment of patients with early-stage melanoma remains controversial. Some surgeons advocate the routine use of elective node dissection in patients with intermediate-thickness primary tumors, but the cost, morbidity, and low yield of tumor-positive lymph nodes associated with this approach make it less appealing than wide excision and observation. Multiple retrospective studies suggest a survival advantage as high as 25% for patients undergoing elective node dissection in the setting of clinically negative nodes, as opposed to delayed node dissection for clinically evident nodal metastases. Although two randomized prospective studies failed to demonstrate a survival advantage in patients undergoing elective node dissection, as compared with those having wide excision alone, both studies were criticized for their design [1,2].