- Historically, patients who have a melanoma-positive sentinel lymph node (SLN) identified by SLNB:
- Had completion lymph node dissection (CLND):
- Pathologic evaluation of CLND specimens:
- Often reveals no additional disease
- Pathologic evaluation of CLND specimens:
- Had completion lymph node dissection (CLND):
- It is important to remember that CLND specimens are routinely assessed with standard histologic techniques rather than the more rigorous approach employed for SLNB specimens:
- As a result, there may be additional disease in the completion node dissection specimen that goes undetected:
- This disease, in theory, represents a potential source of subsequent recurrence if it were not removed:
- CLND performed for microscopic disease provides the potential for improved regional control
- In addition, identifying patients with minimal disease burden by using the SLN approach may help identify the group of patients who may derive an improved survival benefit from early CLND
- Furthermore, knowledge of the pathologic status of the SLNs allows proper staging and thus facilitates decision making regarding adjuvant treatment
- This disease, in theory, represents a potential source of subsequent recurrence if it were not removed:
- As a result, there may be additional disease in the completion node dissection specimen that goes undetected:
- In several studies, when the non-SLNs in a CLND specimen were evaluated by H&E staining and immunohistochemistry:
- Only 8% to 25% of CLND specimens:
- Contained additional nodes with metastatic disease
- Since most patients have metastatic disease identified only in SLNs:
- There has been interest in identifying patients who, despite having a positive SLN, have a low probability of metastatic disease in non-SLNs
- Only 8% to 25% of CLND specimens:
- In an analysis of primary tumor and SLN characteristics:
- The number of SLNs harvested, the Breslow thickness of the primary tumor, and SLN burden (largest focus of metastasis, total area of metastases, number of metastatic foci, and extracapsular extension):
- Most accurately predicted the presence of tumor in non-SLNs
- The number of SLNs harvested, the Breslow thickness of the primary tumor, and SLN burden (largest focus of metastasis, total area of metastases, number of metastatic foci, and extracapsular extension):
- Clinical Relevance:
- Among patients with a positive sentinel lymph node (SLN):
- The presence of metastasis in non-sentinel lymph nodes (NSLNs):
- Which occurs in 8% to 25% of the cases:
- Worsens prognosis
- Which occurs in 8% to 25% of the cases:
- The presence of metastasis in non-sentinel lymph nodes (NSLNs):
- Historically, completion lymph node dissection (CLND) was performed to detect such diseas:
- But is no longer routine due to lack of survival benefit (MSLT-II, DeCOG-SLT):
- However, identifying patients at high risk for NSLN positivity remains important for risk stratification and surveillance planning
- But is no longer routine due to lack of survival benefit (MSLT-II, DeCOG-SLT):
- Among patients with a positive sentinel lymph node (SLN):
- Incidence of NSLN Metastasis:
- Approximately 15% to 20% of patients with a positive SLN will have additional NSLN metastases on CLND
- References:
- Faries MB, Thompson JF, Cochran AJ, et al. N Engl J Med. 2017;376(23):2211–2222.
Leiter U, Stadler R, Mauch C, et al. Lancet Oncol. 2016;17(6):757–767.
- Faries MB, Thompson JF, Cochran AJ, et al. N Engl J Med. 2017;376(23):2211–2222.
- Predictors of NSLN Positivity:
- Several clinicopathologic features are associated with increased likelihood of NSLN involvement please see table
- Reference:
- van Akkooi AC, Nowecki ZI, Voit C, et al. Eur J Cancer. 2008;44(15):2196–2204.
- Predictive Models and Nomograms:
- Several models estimate the risk of NSLN involvement to guide decision-making:
- Rotterdam Criteria:
- Based on size of largest metastasis in SLN
- Dewar Criteria:
- Considers subcapsular vs parenchymal SLN involvement
- Sunbelt Melanoma Trial:
- Proposed a model incorporating tumor burden and other pathologic features
- Rotterdam Criteria:
- References:
- van Akkooi AC, de Wilt JH, Verhoef C, et al. Ann Surg Oncol. 2006;13(10):1511–1518.
- Dewar DJ, Newell B, Green MA, et al. J Clin Pathol. 2004;57(6):602–606.
- Several models estimate the risk of NSLN involvement to guide decision-making:
- Current Practice and Surveillance:
- Routine CLND is no longer recommended for all SLN-positive patients (per MSLT-II and DeCOG-SLT)
- Close nodal basin ultrasound surveillance is now standard
- Patients with high-risk features may be considered for intensified follow-up or adjuvant systemic therapy
- Guidelines:
- NCCN Guidelines for Melanoma, Version 2.2024
- ASCO/SSO Clinical Practice Guidelines
- Prognostic Implications:
- Patients with NSLN involvement have significantly worse melanoma-specific survival (MSS) and recurrence-free survival (RFS) than those with SLN-only disease
- Presence of NSLN metastases upstages patients within AJCC stage IIIC / IIID
- Reference:
- Gershenwald JE, Scolyer RA, Hess KR, et al. CA Cancer J Clin. 2017;67(6):472–492.
- Conclusion:
- While routine CLND is no longer standard, identifying patients at risk for NSLN involvement remains clinically important
- Tumor burden in the SLN, ulceration, and number of positive SLNs are key predictors
- This information is essential for prognostication, risk-adapted surveillance, and selecting candidates for adjuvant therapy
Rodrigo Arrangoiz MS, MD, FACS, FSSO 