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Published on: June 1, 2019
Transection alone is not an indication for sentinel node biopsy in melanoma
Kaiya Kozuma1, Graham Fowler1, Cristian D Valenzuela1
1From the Department of Surgery, Division of Surgical Oncology, Oregon Health & Science University, Portland, OR, USA.
American Journal of Surgery
|June 20, 2026
Summary
Sentinel lymph node biopsy (SNB) for T1a melanoma has low positivity rates, falling below NCCN guidelines. Transection alone is not a significant indication for SNB in melanoma without gross residual tumor.
Area of Science:
- Oncology
- Dermatology
- Surgical Pathology
Background:
- National Comprehensive Cancer Network (NCCN) guidelines suggest sentinel node biopsy (SNB) for melanoma patients with >5% risk of positive SNB (+SNB).
- Guidelines also recommend SNB for melanomas with transected deep margins.
Purpose of the Study:
- To evaluate the utility of SNB in T1 (thin) melanomas, specifically T1a and T1b subtypes.
- To determine if melanoma transection alone is a sufficient indication for SNB.
Main Methods:
- Analysis of a prospective university database of patients undergoing SNB for clinically node-negative melanoma.
- Exclusion of T1 cases with gross residual tumor at initial biopsy sites.
Main Results:
- Overall +SNB rate for T1 melanoma was 3.0% (657 patients).
- T1b melanoma (+SNB rate: 4.9%), T1a melanoma (+SNB rate: 0.4%).
- In 57 cases of transection without gross residual tumor, 0% had positive SNB.
Conclusions:
- +SNB rates for T1a melanoma are below the NCCN threshold for discussion.
- Melanoma transection alone is not a significant indication for SNB when no gross residual tumor is present.
