Identification of Risk Factors in Lymphatic Surgeries for Melanoma: A National Surgical Quality Improvement Program Review

Cost evaluation of the Merlin assay for predicting melanoma sentinel lymph node biopsy metastasis

BACKGROUND

The Merlin assay for melanoma-risk assessment has become commercially available to reduce the rate of unnecessary sentinel lymph node biopsies (SLNB) in SLNB-eligible patients with cutaneous melanoma. Merlin low-risk patients are recommended to undergo wide local excision (WLE) of the primary tumor, whereas Merlin high-risk patients are recommended to undergo both SLNB and WLE. Here, we compared the cost of a Merlin testing strategy to that of a no-testing strategy (usual care) before prescribing SLNB.

METHODS

We identified T1 and T2 patients who underwent WLE and SLNB but not completion lymph node dissection between 2007 and 2018. Controls were T1 patients who only underwent WLE. Costs for WLE and SLNB were calculated by converting institutional cost data to standardized Medicare reimbursement rates. We then developed a decision tree to compare the cost of Merlin testing to that of a no-testing strategy (usual care).

RESULTS

The average standardized cost of WLE was $2066, whereas the cost of WLE and SLNB was $11,976 based on Medicare rates. At a cost below $7350 for T1b melanoma and $4600 for T1b to T2 melanoma, Merlin testing was cost-saving compared to a no-testing strategy (usual care), assuming Medicare reimbursement rates.

CONCLUSION

Merlin testing for T1b and T2 melanoma is potentially cost saving depending on the cost of the molecular assay and SLNB reimbursement rates. In addition to being cost saving, Merlin is expected to improve health-related quality of life.

Fungal signatures of oral disease reflect environmental degradation in a facultative avian scavenger

Degradation of natural ecosystems increases the risk of infections in wildlife due to microbiota dysbiosis. However, little is known about its influence on the development of fungal communities in predators and facultative avian scavengers. We evaluated the incidence of oral disease in wild nestling black kites (Milvus migrans) under contrasting environmental degradation conditions, and explored their oral fungal patterns using molecular methods and multivariate analysis. Oral lesions were found in 36.8% of the 38 nestlings examined in an anthropogenically altered habitat (southeastern Madrid, Spain), but in none of the 105 nestlings examined in a well-conserved natural area (Doñana National Park, Spain). In a subsample of 48 black kites, the composition of the oral fungal community differed among symptomatic nestlings from Madrid (SM) and asymptomatic nestlings from Madrid (AM) and Doñana (AD). Opportunistic fungal pathogens (e.g., Fusarium incarnatum-equiseti species complex, Mucor spp., Rhizopus oryzae) were more prevalent in SM and AM than in AD. Hierarchical clustering and principal component analyses revealed that fungal patterns were distinct between both study areas, and that anthropogenic and natural environmental factors had a greater impact on them than oral disease. Fungal signatures associated with anthropogenic and natural stresses harbored some taxa that could be used to flag oral infection (F. incarnatum-equiseti species complex and Alternaria), indicate environmental degradation (Alternaria) or provide protective benefits in degraded environments (Trichoderma, Epicoccum nigrum and Sordaria). Co-occurrence associations between potentially beneficial and pathogenic fungi were typical of AM and AD, hinting at a possible role in host health. This study shows that early-life exposure to highly degraded environments induces a shift towards a higher prevalence of pathogenic species in the oral cavity of black kites, favoring oral disease. Furthermore, our findings suggest potential ecological applications of the monitoring of oral mycobiome as a bioindication of oral disease and environmental degradation.

Validation of CP-GEP (Merlin Assay) for predicting sentinel lymph node metastasis in primary cutaneous melanoma patients: A U.S. cohort study

BACKGROUND

Approximately 85% of melanoma patients who undergo a sentinel lymph node biopsy (SLNB) are node-negative. Melanoma incidence is highest in patients ≥65 years, but their SLNB positivity rate is lower than in younger patients. CP-GEP, a model combining clinicopathologic and gene expression variables, identifies primary cutaneous melanoma (CM) patients who may safely forgo SLNB due to their low risk for nodal metastasis. Here, we validate CP-GEP in a U.S. melanoma patient cohort.

METHODS

A cohort of 208 adult patients with primary CM from the Mayo Clinic and West Virginia University was used. Patients were stratified according to their risk for nodal metastasis: CP-GEP High Risk and CP-GEP Low Risk. The main performance measures were SLNB reduction rate (RR) and negative predictive value (NPV).

RESULTS

SLNB positivity rate for the entire cohort was 21%. Most patients had a T1b (34%) or T2a (31%) melanoma. In the T1-T2 group (153 patients), CP-GEP achieved an SLNB RR of 41.8% (95% CI: 33.9-50.1) at an NPV of 93.8% (95% CI: 84.8-98.3). Subgroup analysis showed similar performance in T1-T2 patients ≥65 years of age (51 patients; SLNB positivity rate, 9.8%): SLNB RR of 43.1% (95% CI: 29.3-57.8) at an NPV of 95.5% (95% CI: 77.2-99.9).

CONCLUSION

We confirmed the potential of CP-GEP to reduce negative SLNB in all relevant age groups. Our findings are especially relevant to patients ≥65 years, where surgery is often elective. CP-GEP may guide SLNB decision-making in clinical practice.

Model Combining Tumor Molecular and Clinicopathologic Risk Factors Predicts Sentinel Lymph Node Metastasis in Primary Cutaneous Melanoma

PURPOSE

More than 80% of patients who undergo sentinel lymph node (SLN) biopsy have no nodal metastasis. Here we describe a model that combines clinicopathologic and molecular variables to identify patients with thin and intermediate thickness melanomas who may forgo the SLN biopsy procedure due to their low risk of nodal metastasis.

PATIENTS AND METHODS

Genes with functional roles in melanoma metastasis were discovered by analysis of next generation sequencing data and case control studies. We then used PCR to quantify gene expression in diagnostic biopsy tissue across a prospectively designed archival cohort of 754 consecutive thin and intermediate thickness primary cutaneous melanomas. Outcome of interest was SLN biopsy metastasis within 90 days of melanoma diagnosis. A penalized maximum likelihood estimation algorithm was used to train logistic regression models in a repeated cross validation scheme to predict the presence of SLN metastasis from molecular, clinical and histologic variables.

RESULTS

Expression of genes with roles in epithelial-to-mesenchymal transition (glia derived nexin, growth differentiation factor 15, integrin β3, interleukin 8, lysyl oxidase homolog 4, TGFβ receptor type 1 and tissue-type plasminogen activator) and melanosome function (melanoma antigen recognized by T cells 1) were associated with SLN metastasis. The predictive ability of a model that only considered clinicopathologic or gene expression variables was outperformed by a model which included molecular variables in combination with the clinicopathologic predictors Breslow thickness and patient age; AUC, 0.82; 95% CI, 0.78-0.86; SLN biopsy reduction rate of 42% at a negative predictive value of 96%.

CONCLUSION

A combined model including clinicopathologic and gene expression variables improved the identification of melanoma patients who may forgo the SLN biopsy procedure due to their low risk of nodal metastasis.

The Importance of Reproducibility in Plastic Surgery Research

With the advent of big data and database-driven research, the need for reproducible methods has become especially relevant. Given the rise of evidence-based practice, it is crucial to ensure that findings making use of big data can be consistently replicated by other physician-scientists. A call for transparency and reproducibility must occur at the individual, institutional, and national levels. Given the rising popularity of national and large databases in research, the responsibility of authors to ensure reproducibility of clinical research merits renewed discussion. In this article, the authors offer strategies to increase clinical research reproducibility at both the individual and institutional levels, within the context of plastic surgery.

Complications and Sequelae After Sentinel Lymph Node Biopsy in Melanoma: A Retrospective Cohort Study

BACKGROUND AND OBJECTIVE

Sentinel lymph node (SLN) biopsy is a staging, not a therapeutic, procedure. The benefits of SLN biopsy have been more modest than expected and could be outweighed by the risks, which remain unclear. The aim of this study was to describe complications and sequelae observed in patients with melanoma who underwent routine SLN biopsy at our hospital.

PATIENTS AND METHODS

In this retrospective cohort study, we performed a chart review of all patients with melanoma who underwent SLN biopsy at our hospital in Vigo, Spain, between January 2011 and July 2017.

RESULTS

In the period analyzed, 124 SLN biopsies were performed. Over a mean follow-up of 52.7 months (range 10.8-88.7 months). A percentage of 37.9 of the patients experienced complications. The complication rate after excluding patients who underwent lymph node dissection was 30.9%. In the full chort group, there were 14 scar-related complications (11.3%), 13 surgical wound infections (10.5%), 12 lymphedemas (9.7%), 11 seromas (8.9%), 4 hematomas (3.2%), 4 wound dehiscences (3.2%), 2 cases of lymphorrhagia (1.6%), 2 cases of sensitivity alteration (1.6%), and one urinary tract infection (0.8%). The most common sequela was lymphedema. Sequelae were on record for 15.3% of patients in the full cohort (7.5% of the patients who did not undergo lymphadenectomy). Smoking was associated with a 33 to 73% increased risk of complications. The main limitation of this study is the risk of information bias due to incomplete follow-up.

CONCLUSIONS

SLN biopsy is a melanoma staging procedure that causes complications and sequelae. Recommendations for its use in clinical practice guidelines should be revised and the risks and benefits carefully evaluated in each case. Smokers in particular seem to have a high risk of complications. Patients with melanoma could benefit greatly from the development of less invasive staging tools.

Guidance of sentinel lymph node biopsy decisions in patients with T1–T2 melanoma using gene expression profiling

Aim: Can gene expression profiling be used to identify patients with T1–T2 melanoma at low risk for sentinel lymph node (SLN) positivity? Patients & methods: Bioinformatics modeling determined a population in which a 31-gene expression profile test predicted <5% SLN positivity. Multicenter, prospectively-tested (n = 1421) and retrospective (n = 690) cohorts were used for validation and outcomes, respectively. Results: Patients 55–64 years and ≥65 years with a class 1A (low-risk) profile had SLN positivity rates of 4.9% and 1.6%. Class 2B (high-risk) patients had SLN positivity rates of 30.8% and 11.9%. Melanoma-specific survival was 99.3% for patients ≥55 years with class 1A, T1–T2 tumors and 55.0% for class 2B, SLN-positive, T1–T2 tumors. Conclusion: The 31-gene expression profile test identifies patients who could potentially avoid SLN biopsy.