[Sentinel node detection in malignant melanoma. Importance of localization of the primary tumor]

Sentinel node biopsy for melanoma. Analysis of our experience (125 patients)

INTRODUCTION

The objective of this study is to analyze our experience in the use of sentinel node biopsy (SNB) in melanoma and identify the predictive factors of positive SNB and multiple drainage.

MATERIAL AND METHODS

Retrospective study of patients who underwent SNB for melanoma between August of 2000 and February of 2013.

RESULTS

SNB was performed in 125 patients with a median of age of 55,6 (±15) years. The anatomic distribution was: 44 (35,2%) in legs, 24 (19,2%) in arms, 53 (42,4%) trunk and 3 (2,4%) in head and neck. The median Breslow index was 1,81 (0,45-5). Between 1 and 6 nodes were isolated. The drainage was unique in 98 (78,4%) and multiple in 27 (21,6%). The trunk was the localization of 25 (92,6%) nodes with multiple drainage. The definitive result of sentinel node (SN) was positive in 18 cases (7,1%). Breslow thickness (p=0,01) was statistically significant predictor of a positive SNB.

CONCLUSIONS

The SNB allows patients to be selected for lymphadenectomy. Melanoma of the trunk was the principle location of multiple drainage. The only predictive factor of positive SNB was Breslow thickness.

Design and development of (99m)tc-'4+1'-labeled dextran-mannose derivatives as potential radiopharmaceuticals for sentinel lymph node detection

The synthesis, labeling, and biological evaluation of a dextran derivative (DCM-30-iso) as potential radiopharmaceutical for sentinel lymph node imaging is presented. DCM-30-iso bears mannose as active moiety and isocyanide as ligand for technetium through the formation of a '4+1' Tc(III) mixed-ligand complex. A second derivative without mannose (DC-25-iso) was also prepared and evaluated as control. DCM-30-iso and DC-25-iso were synthesized from dextran in four steps (>50% overall yield) and characterized by spectroscopic methods. Labeling with (99m)Tc was achieved by reaction with 2,2',2''-nitrilotris(ethanethiol) and (99m)Tc-EDTA. Radiochemical purity was above 90% and was stable for at least 4 hours postlabeling at 37°C. The identity of the (99m)Tc complex was established through comparative HPLC studies using the well-characterized analogous Re-DC-25-iso complex. Biodistribution and imaging experiments of (99m)Tc-DCM-30-iso showed high uptake in the popliteal lymph node, which could be blocked with preinjection of mannose, and very low uptake in other nodes and organs. The nonmannosylated (99m)Tc-DC-25-iso derivative showed negligible uptake in all lymph nodes. The novel dextran-mannose derivative DCM-30-iso can be successfully labeled with (99m)Tc to give a well-characterized '4+1' complex with favorable biological properties as sentinel lymph node imaging agent.