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Updated: May 6, 2026
Analysis of Lymph Node Volume by Ultra-High-Frequency Ultrasound Imaging in the Braf/Pten Genetically Engineered Mouse Model of Melanoma
Published on: September 8, 2021
Clinicopathologic predictors of sentinel lymph node metastasis in thin melanoma
Dale Han1, Jonathan S Zager, Yu Shyr
1Dale Han, Jonathan S. Zager, Sanjana Iyengar, Mia Djulbegovic, Jaimie L. Weber, Suroosh S. Marzban, Vernon K. Sondak, and Jane L. Messina, Moffitt Cancer Center, Tampa; Eli Avisar, University of Miami, Miami, FL; Yu Shyr, Heidi Chen, and Lynne D. Berry, Vanderbilt University School of Medicine, Nashville, TN; John T. Vetto, Oregon Health and Science University, Portland, OR; Richard L. White, Carolinas Medical Center, Charlotte, NC; Barbara Pockaj, Mayo Clinic, Scottsdale; Robert Krouse, Southern Arizona Veterans Administration Health Care System, Tucson, AZ; Nicola Mozzillo, Istituto Nazionale dei Tumori-Fondazione Pascale, Naples, Italy; Kim James Charney, St Joseph Hospital, Orange; and Mohammed Kashani-Sabet and Stanley P. Leong, California Pacific Medical Center and Research Institute, San Francisco, CA.
Purpose:
Indications for sentinel lymph node biopsy (SLNB) for thin melanoma are continually evolving. We present a large multi-institutional study to determine factors predictive of sentinel lymph node (SLN) metastasis in thin melanoma.
Patients And Methods:
Retrospective review of the Sentinel Lymph Node Working Group database from 1994 to 2012 identified 1,250 patients who had an SLNB and thin melanomas (≤ 1 mm). Clinicopathologic characteristics were correlated with SLN status and outcome.
Results:
SLN metastases were detected in 65 (5.2%) of 1,250 patients. On univariable analysis, rates of Breslow thickness ≥ 0.75 mm, Clark level ≥ IV, ulceration, and absence of regression differed significantly between positive and negative SLN groups (all P < .05). These four variables and mitotic rate were used in multivariable analysis, which demonstrated that Breslow thickness ≥ 0.75 mm (P = .03), Clark level ≥ IV (P = .05), and ulceration (P = .01) significantly predicted SLN metastasis with 6.3%, 7.0%, and 11.6% of the patients with these respective characteristics having SLN disease. Melanomas < 0.75 mm had positive SLN rates of < 5% regardless of Clark level and ulceration status. Median follow-up was 2.6 years. Melanoma-specific survival was significantly worse for patients with positive versus negative SLNs (P = .001).
Conclusion:
Breslow thickness ≥ 0.75 mm, Clark level ≥ IV, and ulceration significantly predict SLN disease in thin melanoma. Most SLN metastases (86.2%) occur in melanomas ≥ 0.75 mm, with 6.3% of these patients having SLN disease, whereas in melanomas < 0.75 mm, SLN metastasis rates are < 5%. By using a 5% metastasis risk threshold, SLNB is indicated for melanomas ≥ 0.75 mm, but further study is needed to define indications for SLNB in melanomas < 0.75 mm.
