Proximity of the primary tumour to the nymph node basin and sentinel node positivity

October 7, 2017

Abstract

Introduction 

A retrospective study of melanoma patients looking at whether proximity of the primary skin tumour to the lymph node basin influences the chance of sentinel lymph node positivity.

Methods

600 patients undergoing sentinel node biopsy for malignant melanoma of upper or lower extremity, using the “10% rule”, were divided into those with a primary melanoma proximal or distal to the knee joint, (up to the ankle), and proximal and distal to the elbow (up to the wrist).
Clinical stage of disease which is known to be related to sentinel node positivity, is taken into account.

Results

600 patients treated for malignant melanoma of the extremities between January 2009 and March 2017 were included in the study. The age of the patients ranged from 24 to 94 years. The Breslow thickness ranged from 1 to 4 mm. The clinical staging ranged from 1A to 2B.

When broken down by anatomical site of the primary, 18 of the 88 patients (20.5%) with lesions on the arm were found to have positive lymph nodes compared to only 4 of the 31 patients (12.9%) with lesions on the forearm. Furthermore, 11 of 58 patients (19.0%) with lesions on the thigh were found to have positive lymph nodes, compared to only 19 of the 135 patients (14.0%) with lesions on the leg. The increase in rate of lymph node positivity when moving from distal to proximal along the limb, approached statistical significance (Z-score 1.4208, p=0.07). The stage of disease was taken into account and on comparison of proximal and distal sites, the stage of disease were comparable (Chi-squared test p=0.55.)

Conclusion

In patients with malignant melanoma involving the limbs, the proximity of the primary skin tumour to the lymph node basin may have influence on sentinel lymph node positivity.  A limitation of this study is the potential variability in the volume of dye injected may have an effect on the results.

Source:

Hunt, D, et al. Does Proximity of the Primary Tumour to the Lymph Node Basin, in Patients with Malignant Melanoma, Influence the Chance of Sentinel Node Positivity?  Plastic and Reconstructive Surgery - Global Open. 5(9S):78–79, SEP 2017  DOI: 10.1097/01.GOX.0000526276.42537.69
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