C. Silvestri1, A. Christopher1, C. Intenzo2, J. Kairys1, S. Kim2, A. Willis1, A. C. Berger1 1Sidney Kimmel Medical College At Thomas Jefferson University,Surgery,Philadelphia, PA, USA 2Thomas Jefferson University Hospital,Nuclear Medicine/Radiology,Philadelphia, PA, USA
Introduction:
Sentinel lymph node biopsy (SLNB) is the current standard of care for patients diagnosed with melanoma >1mm. Preoperative lymphoscintigraphy with radiolabeled isotopes is essential to localize sentinel nodes for removal. Our study compared the effectiveness of Lymphoseek to standard sulfur colloids (SC) during lymphoscintigraphy in patients with melanoma undergoing SLNB.
Methods:
We queried our IRB-approved melanoma database at Thomas Jefferson University to identify 370 consecutive patients who underwent SLNB between 2012-2016 and at least one year of follow up. There were 185 patients who underwent SLNB with the standard SC, and 185 patients who underwent SLNB with Lymphoseek. Data points included primary characteristics of the melanoma (primary site, Breslow thickness, ulceration), lymphoscintigraphy (dosage of radiotracer, mapping time), and SLNB (number of sentinel nodes removed, number of positive sentinel nodes, and false negatives). Student’s t-test and Chi-Square were used to analyze the data with a p-value of <0.05 being considered significant.
Results:
Between the two groups, patients were equally matched in regard to age, sex, and primary characteristics of their melanoma including thickness, primary site, and presence of ulceration. In comparison to SC, Lymphoseek required lower radiation dosages (p<0.001), shorter mapping times (p=0.008), and decreased number of sentinel nodes removed (p=0.03). There was no difference in the number of patients with positive nodes (p=0.5). Additionally, there were no statistical differences between the two radioactive tracers in regard to average number of hot spots per basin, or the number of patients with false negative SLNB.
Conclusion:
Lymphoseek has the potential to decrease radioactivity and mapping time in patients who need SLNB. With a decrease in the number of nodes removed without loss of sensitivity, there is a potential to avoid unnecessary node removal and thus complications such as lymphedema. Longer follow-up will help to determine if there is any increase in false negative rates despite fewer nodes removed.