Standardizing Retrospective Observational Research in Cutaneous Squamous Cell Carcinoma: Expert Panel Guidelines from ITSCC.

Importance: Cutaneous squamous cell carcinoma (CSCC) is the second most common malignant disease in the US. Although it typically carries a good prognosis, a subset of CSCCs are highly aggressive, carrying regional and distant metastatic potential. Due to its high incidence, this aggressive subset is responsible for considerable mortality, with an overall annual mortality estimated to equal or even surpass melanoma. Despite this morbidity, CSCC is excluded from national cancer registries, making it difficult to study its epidemiology and outcomes. Therefore, the bulk of the CSCC literature is composed of single-center and multi-institutional retrospective cohort analyses. Given variations in reporting measures and analyses in these studies, interpretability between studies and the ability to pool results are limited. Objective: To define standardized reporting measures for retrospective CSCC studies. Findings: An expert panel was convened to determine standardized guidelines for recording and analyzing retrospective CSCC data. A total of 13 dermatologists and dermatologic surgeons with more than 5 years of posttraining experience and considerable experience with performing CSCC outcomes research were recruited to the panel. Consensus recommendations were achieved for CSCC retrospective study reporting measures, definitions, and analyses. Conclusions and Relevance: The recommendations in this report present the potential to standardize future CSCC retrospective studies. With such standardization, future work may have greater interstudy interpretability and allow for pooled analyses.

CD73 Is an Immunometabolic Biomarker of Poor Prognosis in Patients With Primary Cutaneous Squamous Cell Carcinoma and Hematologic Malignancy.

BACKGROUND: Impaired immunity may drive the increased incidence and aggression of cutaneous squamous cell carcinoma (cSCC) in patients with hematologic malignancy; however, precise mechanisms and prognostic biomarkers remain undefined. CD73 maintains elevated immunosuppressive adenosine levels and is associated with poor prognosis in several tumor microenvironments. OBJECTIVE: Identify poor outcome biomarkers in patients with cSCC and hematologic malignancy. MATERIALS AND METHODS: Differentially expressed genes in tumors from patients with hematologic malignancy experiencing good (n = 8) versus poor (n = 7) outcomes were identified by NanoString analysis. Results were validated at the protein level using CD73 immunohistochemistry in cSCC patients with (n = 38) and without (n = 29) hematologic malignancy. RESULTS: Forty-eight genes were differentially expressed in tumors from patients with hematologic malignancy experiencing good versus poor outcomes. CD73 gene expression was >2-fold higher in patients with poor versus good outcomes or normal skin. Significantly increased CD73 protein levels were observed in cSCC tumors with poor versus good outcomes from patients with hematologic malignancies (p < .01), whereas no differences were noted in tumors with poor versus good outcomes from patients without hematologic malignancies (p = .49). CONCLUSION: CD73 is highly expressed in poor prognosis cSCC from patients with hematologic malignancy and may represent a useful biomarker and potential therapeutic target.

Establishing Consensus for Mohs Micrographic Surgical Techniques in the Treatment of Melanoma in Situ for Future Clinical Trials: A Modified Delphi Study.

BACKGROUND: Mohs micrographic surgery (MMS) is a promising treatment modality for melanoma in situ (MIS). However, variations in surgical technique limit the generalizability of existing data and may impede future study of MMS in clinical trials. METHODS: A modified Delphi method was selected to establish consensus on optimal MMS techniques for treating MIS in future clinical trials. The Delphi method was selected due to the limited current data, the wide range of techniques used in the field, and the intention to establish a standardized technique for future clinical trials. A literature review and interviews with experienced MMS surgeons were performed to identify dimensions of the MMS technique for MIS that (1) likely impacted costs or outcomes of the procedure, and (2) showed significant variability between surgeons. A total of 8 dimensions of technical variation were selected. The Delphi process consisted of 2 rounds of voting and commentary, during which 44 expert Mohs surgeons across the United States rated their agreement with specific recommendations using a Likert scale. RESULTS: Five of eight recommendations achieved consensus in Round 1. All 3 of the remaining recommendations achieved consensus in Round 2. Techniques achieving consensus in Round 1 included the use of a starting peripheral margin of ≤5 mm, application of immunohistochemistry, frozen tissue processing, and resecting to the depth of subcutaneous fat. Consensus on the use of Wood's lamp, dermatoscope, and negative tissue controls was established in Round 2. CONCLUSIONS: This study generated 8 consensus recommendations intended to offer guidance for Mohs surgeons treating MIS. The adoption of these recommendations will promote standardization to facilitate comparisons of aggregate data in multicenter clinical trials.

Artificial Intelligence in Dermatology: A Systematic Review of Its Applications in Melanoma and Keratinocyte Carcinoma Diagnosis.

BACKGROUND: Limited access to dermatologic care may pose an obstacle to the early detection and intervention of cutaneous malignancies. The role of artificial intelligence (AI) in skin cancer diagnosis may alleviate potential care gaps. OBJECTIVE: The aim of this systematic review was to offer an in-depth exploration of published AI algorithms trained on dermoscopic and macroscopic clinical images for the diagnosis of melanoma, basal cell carcinoma, and cutaneous squamous cell carcinoma (cSCC). METHODS: Adhering to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, a systematic review was conducted on peer-reviewed articles published between January 1, 2000, and January 26, 2023. RESULTS AND DISCUSSION: Among the 232 studies in this review, the overall accuracy, sensitivity, and specificity of AI for tumor detection averaged 90%, 87%, and 91%, respectively. Model performance improved with time. Despite seemingly impressive performance, the paucity of external validation and limited representation of cSCC and skin of color in the data sets limits the generalizability of the current models. In addition, dermatologists coauthored only 12.9% of all studies included in the review. Moving forward, it is imperative to prioritize robustness in data reporting, inclusivity in data collection, and interdisciplinary collaboration to ensure the development of equitable and effective AI tools.

High-volume facilities are significantly more likely to use guideline-adherent systemic immunotherapy for metastatic Merkel cell carcinoma: implications for cancer care regionalization.

Merkel cell carcinoma (MCC) is a neuroendocrine skin cancer with a high rate of mortality. While still relatively rare, the incidence of MCC has been rapidly rising in the US and around the world. Since 2017, two immunotherapeutic drugs, avelumab and pembrolizumab, have been FDA-approved for the treatment of metastatic MCC and have revolutionized outcomes for MCC. However, real-world outcomes can differ from clinical trial data, and the adoption of novel therapeutics can be gradual. We aimed to characterize the treatment practices and outcomes of patients with metastatic MCC across the US. A retrospective cohort study of adult cases of MCC in the National Cancer Database diagnosed from 2004 to 2019 was performed. Multivariable logistic regressions to determine the association of a variety of patient, tumor, and system factors with likelihood of receipt of systemic therapies were performed. Univariate Kaplan-Meier and multivariable Cox survival regressions were performed. We identified 1017 cases of metastatic MCC. From 2017 to 2019, 54.2% of patients received immunotherapy. This increased from 45.1% in 2017 to 63.0% in 2019. High-volume centers were significantly more likely to use immunotherapy (odds ratio 3.235, p = 0.002). On univariate analysis, patients receiving systemic immunotherapy had significantly improved overall survival (p < 0.001). One-, 3-, and 5-year survival was 47.2% (standard error [SE] 1.8%), 21.8% (SE 1.5%), and 16.5% (SE 1.4%), respectively, for patients who did not receive immunotherapy versus 62.7% (SE 3.5%), 34.4% (SE 3.9%), and 23.6% (SE 4.4%), respectively, for those who did (Fig. 1). In our multivariable survival regression, receipt of immunotherapy was associated with an approximately 35% reduction in hazard of death (hazard ratio 0.665, p < 0.001; 95% CI 0.548-0.808). Our results demonstrate that the real-world survival advantage of immunotherapy for metastatic MCC is similar to clinical trial data. However, many patients with metastatic disease did not receive this guideline-recommended therapy in our most recent study year, and use of immunotherapy is higher at high-volume centers. This suggests that regionalization of care to high-volume centers or dissemination of their practices, may ultimately improve patient survival.

The Novel Checkpoint Target Lymphocyte-Activation Gene 3 Is Highly Expressed in Cutaneous Squamous Cell Carcinoma.

BACKGROUND: Lymphocyte activation-gene 3 (LAG-3) is an emerging next-generation immune checkpoint molecule. We aim to define the expression pattern of LAG-3 in cutaneous squamous cell carcinoma (cSCC) as a first step to understand the role of LAG-3 in cSCC prognosis and therapy. OBJECTIVE: To define the expression pattern of LAG-3 in cSCC as a first step to understand the role of LAG-3 in cSCC prognosis and therapy. METHODS: To test whether LAG-3 is expressed on cSCC infiltrating lymphocytes, we isolated CD8 + T lymphocytes from three SCC tumors using flow cytometry and performed single-cell RNA sequencing for LAG-3 and programmed cell death protein -1 (PD-1). In addition, we evaluated LAG-3 mRNA expression in formalin-fixed, paraffin-embedded tissue using NanoString technology. RESULTS: Single-cell RNA sequencing showed that LAG-3 is expressed more than PD-1 in CD8 + tumor infiltrating lymphocytes (50.8% vs 35.2%, respectively). Quantifying LAG-3 mRNA expression showed that compared with normal skin, LAG-3 mRNA is approximately 8 fold higher in immunocompetent associated SCC tumors and approximately 2 fold higher in transplant associated SCC tumors ( p -values <.05). In addition, LAG-3 mRNA was expressed 7.2 fold higher in T2a SCC tumors compared with normal skin ( p -value <.05). CONCLUSION: Lymphocyte activation-gene 3 is expressed on SCC infiltrating T lymphocytes at a higher percentage than PD-1. In addition, LAG-3 mRNA expression is significantly higher in SCC tumors. Ongoing studies will be performed to define its role as an immune-related biomarker and as a therapeutic target.

Evaluating Rates of Positive Margins After Standard Excision of Cutaneous Adnexal Malignancies.

BACKGROUND: It is recommended to excise adnexal neoplasms with standard local excision or Mohs micrographic surgery (MMS), although many occur on high-risk sites such as the head and neck (H&N) and exhibit subclinical extension. Minimal evidence exists on the efficacy of standard excisions for these tumors. OBJECTIVE: To evaluate the rate of positive surgical margins after standard excision of adnexal tumors. METHODS: Retrospective cohort study of cutaneous adnexal malignancies from the National Cancer Database diagnosed from 2004 to 2019. RESULTS: The authors identified a total of 4,402 cases treated with standard excision. Tumors on the H&N were approximately twice as likely as those on the trunk and extremities (T&E) to be excised with positive margins (odds ratio 2.146, p < .001), with the highest estimated rate for eccrine adenocarcinoma (12.1%, SE: 2.3%). The subtype with the highest positive margin rate on the T&E was microcystic adnexal carcinoma (8.0%, SE: 2.9). Positive margins were associated with poorer overall survival on multivariable survival analysis (hazard ratio 1.299, p = .015). CONCLUSION: The authors present subtype- and site-specific positive margin rates for adnexal tumors treated with standard excision, which suggest that tumors on the H&N and some T&E subtypes, should be considered for MMS.

Overall Survival After Mohs Surgery for Early-Stage Merkel Cell Carcinoma.

Importance: Merkel cell carcinoma (MCC) is a rare cutaneous malignant neoplasm with increasing incidence and high mortality. Although it is accepted that the optimal treatment for localized tumors is surgical, the data surrounding the optimal surgical approach are mixed, and current National Comprehensive Cancer Network guidelines state that Mohs micrographic surgery (MMS) and wide local excision (WLE) can both be used. The current National Comprehensive Cancer Network guidelines do not advocate a preference for MMS or WLE and suggest that they can be used interchangeably. Objective: To evaluate the association of surgical approach with overall survival after excision of localized T1/T2 MCC. Design, Setting, and Participants: This retrospective cohort study used the National Cancer Database to assess adults with T1/T2 MCC who were diagnosed between January 1, 2004, and December 31, 2018, with pathologically confirmed, negative regional lymph nodes and treated with surgery. The National Cancer Database includes all reportable cases from Commission on Cancer-accredited facilities. Data analysis was performed from October 2022 to May 2023. Exposure: Surgical approach. Main Outcomes and Measures: Overall survival. Results: A total of 2313 patients (mean [SD] age, 71 [10.6] years; 1340 [57.9%] male) were included in the study. Excision with MMS had the best unadjusted survival, with mean (SE) survival rates of 87.4% (3.4%) at 3 years, 84.5% (3.9%) at 5 years, and 81.8% (4.6%) at 10 years vs 86.1% (0.9%) at 3 years, 76.9% (1.2%) at 5 years, and 60.9% (2.0%) at 10 years for patients treated with WLE. Patients treated with narrow-margin excision had similar survival as those treated with WLE, with mean (SE) survival rates of 84.8% (1.4%) at 3 years, 78.3% (1.7%) at 5 years, and 60.8% (3.6%) at 10 years. On multivariable survival analysis, excision with MMS was associated with significantly improved survival compared with WLE (hazard ratio, 0.59; 95% CI, 0.36-0.97; P = .04). High-volume MCC centers were significantly more likely to use MMS over WLE compared with other centers (odds ratio, 1.99; 95% CI, 1.63-2.44; P < .001). Conclusions and Relevance: In this cohort study, the use of MMS (compared with WLE) was associated with significantly improved survival for patients with localized MCC with pathologically confirmed negative lymph nodes treated with surgery. These data suggest that Mohs surgery may provide a more effective treatment for MCC primary tumors than conventional WLE, although the lack of randomization and potential for selection bias in this study highlight the need for future prospective work evaluating this issue.

Spatial transcriptomics stratifies psoriatic disease severity by emergent cellular ecosystems.

Whereas the cellular and molecular features of human inflammatory skin diseases are well characterized, their tissue context and systemic impact remain poorly understood. We thus profiled human psoriasis (PsO) as a prototypic immune-mediated condition with a high predilection for extracutaneous involvement. Spatial transcriptomics (ST) analyses of 25 healthy, active lesion, and clinically uninvolved skin biopsies and integration with public single-cell transcriptomics data revealed marked differences in immune microniches between healthy and inflamed skin. Tissue-scale cartography further identified core disease features across all active lesions, including the emergence of an inflamed suprabasal epidermal state and the presence of B lymphocytes in lesional skin. Both lesional and distal nonlesional samples were stratified by skin disease severity and not by the presence of systemic disease. This segregation was driven by macrophage-, fibroblast-, and lymphatic-enriched spatial regions with gene signatures associated with metabolic dysfunction. Together, these findings suggest that mild and severe forms of PsO have distinct molecular features and that severe PsO may profoundly alter the cellular and metabolic composition of distal unaffected skin sites. In addition, our study provides a valuable resource for the research community to study spatial gene organization of healthy and inflamed human skin.

Defining and quantifying histopathologic risk factors for regional and distant metastases in a large cohort of vulvar squamous cell carcinomas.

BACKGROUND: Vulvar squamous cell carcinoma (vSCC) is a rare tumor with a good prognosis when treated at a localized stage. However, once regional/distant metastasis occurs, vSCC can be rapidly fatal. Thus, it is important to identify tumor prognostic features so that high-risk cases can be prioritized for further diagnostic workup and treatment. OBJECTIVE: To estimate the risk of regional/distant metastasis at presentation and sentinel lymph node status for vSCC based on histopathologic characteristics. METHODS: A retrospective cohort study of 15,188 adult vSCC cases from the National Cancer Database diagnosed from 2012 to 2019. RESULTS: We provide specific estimates of the risk of clinically positive nodes and metastatic disease at presentation and sentinel lymph node positivity according to tumor size, moderate/poor tumor differentiation, and lymph-vascular invasion. These histopathologic factors were all significantly associated with the tested clinical outcomes in a multivariable analysis. Moderate (hazard ratio, 1.190; P < .001) and poor differentiation (hazard ratio, 1.204; P < .001) and lymph-vascular invasion (hazard ratio, 1.465; P < .001) were also associated with significantly poorer overall survival. LIMITATIONS: Data on disease-specific survival not available in the data set. CONCLUSIONS: We demonstrate the association of the histopathologic characteristics of vSCC with clinically important outcomes. These data may provide individualized information when discussing diagnostic/treatment recommendations, particularly regarding sentinel lymph node biopsy. These data may also guide future staging and risk stratification efforts for vSCC.