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

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.

Unmeasured factors are associated with the use of completion lymph node dissection (CLND) in melanoma

BACKGROUND

Completion lymph node dissection (CLND) was the standard treatment for patients with melanoma with positive sentinel lymph nodes (SLN) until 2017 when data from the DeCOG-SLT and MLST-2 randomized trials challenged the survival benefit of this procedure. We assessed the contribution of patient, tumor and facility factors on the use of CLND in patients with surgically resected Stage III melanoma.

METHODS

Using the National Cancer Database, patients who underwent surgical excision and were found to have a positive SLN from 2012 to 2017 were included. A multivariable mixed-effects logistic regression model with a random intercept for the facility was used to determine the effect of patient, tumor, and facility variables on the risk of CLND. Reference effect measures (REMs) were used to compare the contribution of contextual effects (unknown facility variables) versus measured variables on the variation in CLND use.

RESULTS

From 2012 to 2017, the overall use of CLND decreased from 59.9% to 26.5% (p < 0.0001). Overall, older patients and patients with government-based insurance were less likely to undergo CLND. Tumor factors associated with a decreased rate of CLND included primary tumor location on the lower limb, decreasing depth, and mitotic rate <1. However, the contribution of contextual effects to the variation in CLND use exceeded that of the measured facility, tumor, time, and patient variables.

CONCLUSIONS

There was a decrease in CLND use during the study period. However, there is still high variability in CLND use, mainly driven by unmeasured contextual effects.

Current Controversies in Melanoma Treatment

LEARNING OBJECTIVES

After reading this article and viewing the videos, the participant should be able to: 1. Discuss margins for in situ and invasive disease and describe reconstructive options for wide excision defects, including the keystone flap. 2. Describe a digit-sparing alternative for subungual melanoma. 3. Calculate personalized risk estimates for sentinel node biopsy using predictive nomograms. 4. Describe the indications for lymphadenectomy and describe a technique intended to reduce the risk of lymphedema following lymphadenectomy. 5. Offer options for in-transit melanoma management.

SUMMARY

Melanoma management continues to evolve, and plastic surgeons need to stay at the forefront of advances and controversies. Appropriate margins for in situ and invasive disease require consideration of the trials on which they are based. A workhorse reconstruction option for wide excision defects, particularly in extremities, is the keystone flap. There are alternative surgical approaches to subungual tumors besides amputation. It is now possible to personalize a risk estimate for sentinel node positivity beyond what is available for groups of patients with a given stage of disease. Sentinel node biopsy can be made more accurate and less morbid with novel adjuncts. Positive sentinel node biopsies are now rarely managed with completion lymphadenectomy. Should a patient require lymphadenectomy, immediate lymphatic reconstruction may mitigate the lymphedema risk. Finally, there are minimally invasive modalities for effective control of in-transit recurrences.

The Evolution of the Sentinel Node Biopsy in Melanoma

The growing repertoire of approved immune-checkpoint inhibitors and targeted therapy has revolutionized the adjuvant treatment of melanoma. While the treatment of primary cutaneous melanoma remains wide local excision (WLE), the management of regional lymph nodes continues to evolve in light of practice-changing clinical trials and dramatically improved adjuvant therapy. With large multicenter studies reporting no benefit in overall survival for completion lymph node dissection (CLND) after a positive sentinel node biopsy (SLNB), controversy remains regarding patient selection and clinical decision-making. This review explores the evolution of the SLNB in cutaneous melanoma in the context of a rapidly changing adjuvant treatment landscape, summarizing the key clinical trials which shaped current practice guidelines.

Multicenter Adoption and Outcomes of Nodal Observation for Patients with Melanoma and Sentinel Lymph Node Metastases

BACKGROUND

Following publication of the MSLT-II trial showing no survival benefit of completion lymphadenectomy (CLND) in patients with melanoma sentinel lymph node (SLN) metastases, it is expected that practice patterns have changed. The purpose of this study is to understand real-world practices and outcomes after publication of this landmark trial.

PATIENTS AND METHODS

Patients with truncal/extremity melanoma SLN metastases diagnosed between 2013 and 2019 at four academic cancer centers were included in this retrospective cohort study. Descriptive statistics, Cox proportional hazards model, and multivariable regression were used to characterize the cohort and identify predictors of CLND, harboring non-SLN (NSLN) metastases, and survival.

RESULTS

Results of 1176 patients undergoing SLN biopsy, 183 had SLN metastases. The number of patients who underwent CLND before versus after trial publication was 75.7.% versus 20.5% (HR 0.16, 95% CI 0.09-0.28). Of those undergoing nodal observation (NO), 92% had a first nodal-basin ultrasound, while 63% of patients had a fourth. In exploratory multivariable analyses, age ≥ 50 years was associated with lower rate of CLND (HR 0.58, 95% CI 0.36-0.92) and larger SLN deposit (> 1.0 mm) with increased rate of CLND (HR 1.87, 95% CI 1.17-3.00) in the complete cohort. Extracapsular extension was associated with increased risk of NSLN metastases (HR 12.43, 95% CI 2.48-62.31). Adjusted survival analysis demonstrated no difference in recurrence or mortality between patients treated with CLND versus NO at median 2.2-year follow-up.

CONCLUSION

Nodal observation was rapidly adopted into practice in patients with melanoma SLN metastases at four centers in Canada. Younger age and higher nodal burden were associated with increased use of CLND after trial publication. Ultrasound (US) surveillance decreased with time from SLNB. In our study, CLND was not associated with a decreased risk of recurrence or mortality.

Surgical Management of Melanoma: Advances and Updates

PURPOSE OF REVIEW

To review and update surgeons about the evolving complexities in the surgical management of melanoma including lymph node staging and treatment.

RECENT FINDINGS

Primary resection with adequate margins continues to be the standard of care for localized cutaneous melanoma. Sentinel lymph node biopsy is confirmed to be a powerful tool due to its prognostic value and informative guidance for adjuvant treatments and surveillance. Due to the lack of benefit in melanoma-specific survival and distant metastasis-free survival, completion lymph node dissection is not performed routinely after a positive sentinel lymph node biopsy. Neoadjuvant systemic treatment approaches for advanced loco-regional disease show promise in phase I and II clinical trial data, and phase III studies. The surgical management of cutaneous melanoma continues to evolve with further de-escalation of the extent of excision of primary melanomas and the management of lymph node disease.

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 ratio_high = 1.49, 95% confidence interval = 1.05-2.12; odds ratio_moderate = 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.

Adjuvant Therapy for Stage III Melanoma Without Immediate Completion Lymph Node Dissection

INTRODUCTION

For patients with stage III melanoma with occult lymph node metastasis, the use of adjuvant therapy is increasing, and completion lymph node dissection (CLND) is decreasing. We sought to evaluate the use of modern adjuvant therapy and outcomes for patients with stage III melanoma who did not undergo CLND.

METHODS

Patients with a positive SLNB from 2015 to 2020 who did not undergo CLND were evaluated retrospectively. Nodal recurrence, recurrence-free survival (RFS), distant metastasis-free survival (DMFS), and melanoma-specific survival were evaluated.

RESULTS

Among 90 patients, 56 (62%) received adjuvant therapy and 34 (38%) underwent observation alone. Patients who received adjuvant therapy were younger (mean age: 53 vs. 65, p < 0.001) and had higher overall stage (Stage IIIb/c 75% vs. 54%, p = 0.041). Disease recurred in 12 of 34 patients (35%) in the observation group and 11 of 56 patients (20%) in the adjuvant therapy group. The most common first site of recurrence was distant recurrence alone (5/34 patients) in the observation group and nodal recurrence alone (8/90 patients) in the adjuvant therapy group. Despite more adverse nodal features in the adjuvant therapy group, 24-month nodal recurrence rate and RFS were not significantly different between the adjuvant and observation cohorts (nodal recurrence rate: 26% vs. 20%, p = 0.68; RFS: 75% vs. 61%, p = 0.39). Among patients with stage IIIb/c disease, adjuvant therapy was associated with a significantly improved 24-month DMFS (86% vs. 59%, p = 0.04).

CONCLUSIONS

In this early report, modern adjuvant therapy in patients who forego CLND is associated with longer DMFS among patients with stage IIIb/c disease.