Nodal radioactivity after lymphoscintigraphy as a guide to sentinel node-positivity in melanoma patients

John F Thompson; Roger F Uren; Kevin London; David Chung; Robyn Pm Saw; Andrew J Spillane; Jonathan R Stretch; Kerwin F Shannon; Julie Howle; Omgo E Nieweg; Sydney Ch'ng; Thomas E Pennington; Alison J Potter; Richard A Scolyer; Gabrielle J Williams

doi:10.1016/j.ejso.2025.110225

Nodal radioactivity after lymphoscintigraphy as a guide to sentinel node-positivity in melanoma patients

Eur J Surg Oncol. 2025 Sep;51(9):110225. doi: 10.1016/j.ejso.2025.110225. Epub 2025 Jun 9.

Authors

Affiliations

¹ Melanoma Institute Australia, The University of Sydney, Sydney, NSW, Australia; Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia; Department of Melanoma and Surgical Oncology, Royal Prince Alfred Hospital, Sydney, NSW, Australia; Faculty of Health and Medical Sciences, The University of Western Australia, Perth, WA, Australia. Electronic address: john.thompson@melanoma.org.au.
² Melanoma Institute Australia, The University of Sydney, Sydney, NSW, Australia; Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia; Alfred Nuclear Medicine and Ultrasound, RPAH Medical Centre, Sydney, NSW, Australia.
³ Melanoma Institute Australia, The University of Sydney, Sydney, NSW, Australia; Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia; Department of Melanoma and Surgical Oncology, Royal Prince Alfred Hospital, Sydney, NSW, Australia.
⁴ Melanoma Institute Australia, The University of Sydney, Sydney, NSW, Australia; Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia; Department of Breast and Melanoma Surgery, Royal North Shore Hospital, Sydney, NSW, Australia.
⁵ Melanoma Institute Australia, The University of Sydney, Sydney, NSW, Australia; Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia; Department of Surgical Oncology, Westmead Hospital, Sydney, NSW, Australia.
⁶ Melanoma Institute Australia, The University of Sydney, Sydney, NSW, Australia; Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia; Faculty of Medicine, The University of New South Wales, Sydney, NSW, Australia; Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, NSW Health Pathology, NSW, Australia.
⁷ Melanoma Institute Australia, The University of Sydney, Sydney, NSW, Australia; Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia; Tissue Pathology and Diagnostic Oncology, Royal Prince Alfred Hospital, NSW Health Pathology, NSW, Australia; Charles Perkins Centre, The University of Sydney, Sydney, NSW, Australia.
⁸ Melanoma Institute Australia, The University of Sydney, Sydney, NSW, Australia; Faculty of Medicine and Health, The University of Sydney, Sydney, NSW, Australia.

PMID: 40614343
DOI: 10.1016/j.ejso.2025.110225

Abstract

Objective: To determine how often the sentinel node (SN) with the highest gamma count after lymphoscintigraphy was metastasis-free in SN-positive melanoma patients.

Background: SN biopsy (SNB) is a standard staging procedure for patients with primary cutaneous melanoma. After pre-operative radiotracer injection, intra-operative gamma counts are used, with blue dye localization, to guide SN retrieval. Sometimes only the "hottest" nodes are removed, but the reliability of predicting SN-positivity on the basis of a node's gamma count is uncertain.

Methods: Patients who had a SNB and in whom ≥2 SNs were removed, at least one of which contained metastatic melanoma, were identified from an institutional database. After preoperative lymphoscintigraphy using Tc-99m antimony sulfide colloid injected at the primary melanoma site, residual radioactivity in SNs was used to assist their intra-operative localization. Gamma counts were recorded for all SNs that were removed, and correlated with SN-positivity on subsequent histopathology.

Results: In 550 of 715 patients with complete data for analysis the "hottest" SN contained metastatic melanoma, but the remaining 165 patients (23 %) had metastatic disease exclusively in a SN with a lower gamma count.

Conclusions: For accurate intraoperative identification of SNs containing metastatic melanoma, gamma counts may be unreliable. The key to accuracy is high-quality lymphoscintigraphy, ideally with SPECT-CT imaging, for precise preoperative identification and localization of SNs. Use of a gamma-detection probe intraoperatively will assist in the search for these pre-operatively identified SNs, but removal of only the "hottest" node will not reliably indicate whether regional node metastasis has occurred.

Keywords: Gamma probe; Lymphoscintigraphy; Melanoma; Sentinel node biopsy.

MeSH terms

Adult
Aged
Aged, 80 and over
Antimony
Female
Humans
Lymphatic Metastasis
Lymphoscintigraphy* / methods
Male
Melanoma* / diagnostic imaging
Melanoma* / pathology
Melanoma* / secondary
Melanoma* / surgery
Middle Aged
Neoplasm Staging
Radiopharmaceuticals
Retrospective Studies
Sentinel Lymph Node Biopsy*
Sentinel Lymph Node* / diagnostic imaging
Sentinel Lymph Node* / pathology
Skin Neoplasms* / diagnostic imaging
Skin Neoplasms* / pathology
Skin Neoplasms* / surgery
Technetium Compounds

Substances

Radiopharmaceuticals
Antimony
technetium Tc 99m antimony sulfide
Technetium Compounds