Performance of models predicting residual lymph node disease in melanoma patients following sentinel lymph node biopsy

Impact of extra-nodal extension and AJCC lymph node staging in predicting recurrence following lymphadenectomy in patients with melanoma

BACKGROUND

Regional lymphadenectomy (RL) has traditionally been recommended in patients with melanoma found to have clinical lymphadenopathy or a positive sentinel lymph node biopsy (SLNB). Regional control of disease is still a relevant issue for patients, even after undergoing lymphadenectomy. The goal of this study was to identify the clinicopathologic characteristics that predict locoregional recurrence in patients who have undergone either therapeutic lymph node dissection (TLND) or completion lymph node dissection (CLND) following SLNB.

METHODS

Retrospective review of population-based cohort of patients with melanoma lymph node metastasis from the years 2005-2015. Multivariate, proportional hazards regression analysis was performed to determine factors predicting nodal recurrence.

RESULTS

586 patients underwent a RL, with a median follow up of 35 months. Overall, in-basin recurrence rates in the axilla, groin, and head/neck were 7.7 ​%, 8.7 ​% and 9.2 ​%, respectively. Higher unadjusted recurrence rates occurred following CLND than TLND of the groin (12.8 ​% vs 4.5 ​%) and neck (10.0 ​% vs 4.7 ​%) but not the axilla (7.5 ​% vs 8.0 ​%). Upon multivariate analysis, ENE (HR 2.77; p=<0.0001) and the AJCC lymph node stage (N3 vs N1) (HR 2.51; p ​= ​0.025) were predictive of regional recurrence.

CONCLUSION

The AJCC nodal stage and the presence of extranodal extension were the only variables impacting regional recurrence following regional lymphadenectomy for melanoma. When considering regional disease control, they should be factored into treatment decisions, and surveillance strategies.

Sentinel lymph node assessment in melanoma: current state and future directions

Assessment of sentinel lymph node status is an important step in the evaluation of patients with melanoma for both prognosis and therapeutic management. Pathologists have an important role in this evaluation. The methodologies have varied over time, from the evaluation of dimensions of metastatic burden to determination of the location of the tumour deposits within the lymph node to precise cell counting. However, no single method of sentinel lymph node tumour burden measurement can currently be used as a sole independent predictor of prognosis. The management approach to sentinel lymph node-positive patients has also evolved over time, with a more conservative approach recently recognised for selected cases. This review gives an overview of past and current status in the field with a glimpse into future directions based on prior experiences and clinical trials.

International Center-Level Variation in Utilization of Completion Lymph Node Dissection and Adjuvant Systemic Therapy for Sentinel Lymph Node-Positive Melanoma at Major Referral Centers

OBJECTIVE

The aim of this study was to determine overall trends and center-level variation in utilization of completion lymph node dissection (CLND) and adjuvant systemic therapy for sentinel lymph node (SLN)-positive melanoma.

SUMMARY BACKGROUND DATA

Based on recent clinical trials, management options for SLN-positive melanoma now include effective adjuvant systemic therapy and nodal observation instead of CLND. It is unknown how these findings have shaped practice or how these contemporaneous developments have influenced their respective utilization.

METHODS

We performed an international cohort study at 21 melanoma referral centers in Australia, Europe, and the United States that treated adults with SLN-positive melanoma and negative distant staging from July 2017 to June 2019. We used generalized linear and multinomial logistic regression models with random intercepts for each center to assess center-level variation in CLND and adjuvant systemic treatment, adjusting for patient and disease-specific characteristics.

RESULTS

Among 1109 patients, performance of CLND decreased from 28% to 8% and adjuvant systemic therapy use increased from 29 to 60%. For both CLND and adjuvant systemic treatment, the most influential factors were nodal tumor size, stage, and location of treating center. There was notable variation among treating centers in management of stage IIIA patients and use of CLND with adjuvant systemic therapy versus nodal observation alone for similar risk patients.

CONCLUSIONS

There has been an overall decline in CLND and simultaneous adoption of adjuvant systemic therapy for patients with SLN-positive melanoma though wide variation in practice remains. Accounting for differences in patient mix, location of care contributed significantly to the observed variation.

Evidence and implementation gaps in management of sentinel node-positive melanoma in the United States

BACKGROUND

Melanoma clinical trials demonstrated that completion lymph node dissection is low value for most sentinel lymph node-positive patients. Contemporaneous trials of adjuvant systemic immunotherapy and BRAF/MEK targeted therapy showed improved recurrence-free survival in high-risk sentinel lymph node-positive patients. To better understand how oncologic evidence is incorporated into practice (implementation), we evaluated factors associated with discontinuation of completion lymph node dissection and adoption of systemic treatment at United States Commission on Cancer-accredited centers.

METHODS

In a retrospective cohort study of adults with sentinel lymph node-positive melanoma treated from 2012 to 2017 using the National Cancer Database, we evaluated use of completion lymph node dissection and adjuvant systemic treatment using mixed-effects logistic regression, reporting results as odds ratios with 95% confidence intervals.

RESULTS

Among 10,240 sentinel lymph node-positive melanoma patients, performance of completion lymph node dissection declined from 60% to 27%. Adjuvant systemic treatment increased from 29% to 43% (37% in stage IIIA patients, 46% in IIIB-C). Completion lymph node dissection was less common with lower extremity tumors (odds ratio = 0.53, 95% confidence interval = 0.44-0.64) and more common with multiple positive sentinel lymph nodes (odds ratio = 2.36, 95% confidence interval = 2.08-2.67), treatment at a high- or moderate-volume center (odds ratiohigh = 1.49, 95% confidence interval = 1.05-2.12; odds ratiomoderate = 1.32, 95% confidence interval = 1.05-1.64), and receipt of systemic therapy (odds ratio = 1.44, 95% confidence interval = 1.27-1.63). The increased likelihood of completion lymph node dissection in patients receiving adjuvant systemic treatment persisted in the most recent study years and in patients with a single positive sentinel lymph node.

CONCLUSION

At a population level, completion lymph node dissection declined and adjuvant systemic treatment increased, reflecting evidence-responsive care. Variation in persistent use of completion lymph node dissection and in provision of adjuvant treatment for lower risk patients highlights residual gaps in both evidence and implementation.

Clinicopathologic models predicting non-sentinel lymph node metastasis in cutaneous melanoma patients: Are they useful for patients with a single positive sentinel node?

Background and Objectives

Of clinically node‐negative (cN0) cutaneous melanoma patients with sentinel lymph node (SLN) metastasis, between 10% and 30% harbor additional metastases in non‐sentinel lymph nodes (NSLNs). Approximately 80% of SLN‐positive patients have a single positive SLN.

Methods

To assess whether state‐of‐the‐art clinicopathologic models predicting NSLN metastasis had adequate performance, we studied a single‐institution cohort of 143 patients with cN0 SLN‐positive primary melanoma who underwent subsequent completion lymph node dissection. We used sensitivity (SE) and positive predictive value (PPV) to characterize the ability of the models to identify patients at high risk for NSLN disease.

Results

Across Stage III patients, all clinicopathologic models tested had comparable performances. The best performing model identified 52% of NSLN‐positive patients (SE = 52%, PPV = 37%). However, for the single SLN‐positive subgroup (78% of cohort), none of the models identified high‐risk patients (SE > 20%, PPV > 20%) irrespective of the chosen probability threshold used to define the binary risk labels. Thus, we designed a new model to identify high‐risk patients with a single positive SLN, which achieved a sensitivity of 49% (PPV = 26%).

Conclusion

For the largest SLN‐positive subgroup, those with a single positive SLN, current model performance is inadequate. New approaches are needed to better estimate nodal disease burden of these patients.

Surveillance of Sentinel Node-Positive Melanoma Patients with Reasons for Exclusion from MSLT-II: Multi-Institutional Propensity Score Matched Analysis

BACKGROUND

In sentinel lymph node (SLN)-positive melanoma, two randomized trials demonstrated equivalent melanoma-specific survival with nodal surveillance vs completion lymph node dissection (CLND). Patients with microsatellites, extranodal extension (ENE) in the SLN, or >3 positive SLNs constitute a high-risk group largely excluded from the randomized trials, for whom appropriate management remains unknown.

STUDY DESIGN

SLN-positive patients with any of the three high-risk features were identified from an international cohort. CLND patients were matched 1:1 with surveillance patients using propensity scores. Risk of any-site recurrence, SLN-basin-only recurrence, and melanoma-specific mortality were compared.

RESULTS

Among 1,154 SLN-positive patients, 166 had ENE, microsatellites, and/or >3 positive SLN. At 18.5 months median follow-up, 49% had recurrence (vs 26% in patients without high-risk features, p < 0.01). Among high-risk patients, 52 (31%) underwent CLND and 114 (69%) received surveillance. Fifty-one CLND patients were matched to 51 surveillance patients. The matched cohort was balanced on tumor, nodal, and adjuvant treatment factors. There were no significant differences in any-site recurrence (CLND 49%, surveillance 45%, p = 0.99), SLN-basin-only recurrence (CLND 6%, surveillance 14%, p = 0.20), or melanoma-specific mortality (CLND 14%, surveillance 12%, p = 0.86).

CONCLUSIONS

SLN-positive patients with microsatellites, ENE, or >3 positive SLN constitute a high-risk group with a 2-fold greater recurrence risk. For those managed with nodal surveillance, SLN-basin recurrences were more frequent, but all-site recurrence and melanoma-specific mortality were comparable to patients treated with CLND. Most recurrences were outside the SLN-basin, supporting use of nodal surveillance for SLN-positive patients with microsatellites, ENE, and/or >3 positive SLN.

Sentinel Node Status is the Most Important Prognostic Information for Clinical Stage IIB and IIC Melanoma Patients

BACKGROUND

Sentinel node biopsy (SNB) for melanoma patients has been questioned. We aimed to study high-risk stage II melanoma patients who underwent SNB to determine what the prognostic factors regarding recurrence and mortality were, and evaluate how relevant SNB status is in this scenario.

METHODS

This was a retrospective analysis of clinical stage IIB/IIC melanoma patients who underwent SNB from 2000 to 2015 in a single institution. Prognostic factors related to distant recurrence-free survival (DRFS) and melanoma-specific survival (MSS) were assessed from multiple Cox regression. Relevant variables were used to create risk predictor nomograms for DRFS and MSS.

RESULTS

From 1213 SNB, 259 were performed for clinical stage IIB/IIC melanoma patients. SNB status was the most important variable for both endpoints. Patients with positive SNB presented median DRFS of 35.73 months (95% CI 21.38-50.08, SE 7.32) and median MSS of 66.4 months (95% CI 29.76-103.03, SE 18.69), meanwhile both median DRFS and MSS were not achieved for those with negative SNB (logrank < 0.0001). Both nomograms have been internally validated and presented adequate calibration (C-index was 0.734 for DRFS and 0.718 for MSS).

CONCLUSIONS

SNB status was the most important risk factor in our cohort of clinical stage IIB and IIC patients and, in conjunction with well-established primary tumor characteristics, should not be abandoned. Their use in prognosis for these patients remains extremely useful for daily practice.