Oncology · Surgery · 10 h ago
A 30% Geiger-count threshold may identify melanoma sentinel nodes
A single-institution retrospective study of 1,001 patients with melanoma compared a 30% Geiger-count threshold with the standard 10% threshold for sentinel lymph node identification. The higher threshold was associated with greater positive predictive value and comparable negative predictive value, but requires prospective evaluation.
- Retrospective analysis included 1,001 melanoma patients.
- A 30% threshold had higher positive predictive value.
- Negative predictive value was comparable with the 10% threshold.
- Prospective validation is needed before protocol changes.
Sentinel lymph node biopsy (SLNB) can carry morbidity, and the conventional approach identifies nodes with at least 10% of the highest Geiger count in a lymph-node basin. Researchers retrospectively reviewed melanoma patients who underwent technetium-99m lymphatic mapping, with or without methylene blue. The analysis included 1,001 patients and 1,098 involved lymph-node basins; patients needed at least two sentinel nodes, preoperative clinical staging, and final pathology data.
The study compared positive and negative predictive values at the 10% and 30% thresholds. The 30% threshold had a higher positive predictive value and a comparable negative predictive value across sampled basins, including when results were stratified by preoperative tumor T stage. The cohort’s calculated optimal threshold was 52.3%.
The findings suggest that a more restrictive threshold could reduce the number of nodes removed without compromising disease detection in this cohort. However, this was an exploratory, retrospective, single-institution study; prospective evaluation is needed before changing SLNB protocols. The source does not provide the predictive-value estimates or details of missed positive nodes, limiting assessment of the trade-off.
In practice
For patients with melanoma undergoing sentinel lymph node biopsy, this single-institution retrospective analysis suggests that using a 30% rather than 10% Geiger-count threshold may identify nodes with higher positive predictive value and comparable negative predictive value. The results do not establish that changing the threshold is safe in routine practice: the study was exploratory, and prospective evaluation is needed. Predictive-value estimates and details about positive nodes not identified at the higher threshold were not provided in the supplied text.
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Annals of Surgical Oncology: Exploring Geiger Count Thresholds for Sentinel Node Identification in Melanoma: Is 10 % Still Optimal? ↗This is an automated AI-condensed summary that has not yet been reviewed by an editor. Always consult the full item at the original source.