European consensus-based interdisciplinary guideline for invasive cutaneous squamous cell carcinoma: Part 2. Treatment-Update 2023

Updates in the Management of Advanced Nonmelanoma Skin Cancer

Basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (cSCC), and Merkel cell carcinoma (MCC) comprise the majority of nonmelanoma skin cancers. Advances have been made in treatment. Sentinel node biopsy should be considered for locally advanced, clinically node-negative cSCCs and MCCs. BCC patients failing traditional surgery and/or radiation are candidates for systemic hedgehog inhibitor therapy. Immune checkpoint inhibitor treatment is available for patients who failed traditional treatment with surgery and/or radiation or who are not candidates for these modalities. Specifically, cemiplimab is approved for advanced BCC; cemiplimab and pembrolizumab for advanced cSCC; and avelumab, pembrolizumab, and retifanlimab-dlwr for recurrent/metastatic MCC.

Ex Vivo Confocal Microscopy Speeds up Surgical Margin Control of Re-Excised Skin Tumors and Greatly Shortens In-Hospital Stay

BACKGROUND/OBJECTIVES

To ensure that non-melanoma skin cancer (NMSC) is completely removed in healthy tissue, micrographically controlled surgery (3D histology) is often performed, which can prolong the inpatient stay. This study examined ex vivo reflectance confocal microscopy (evRCM) for perioperative assessment of surgical margins, specifically in cases where re-excision was necessary due to incomplete removal of cutaneous tumor tissue.

METHODS

NMSC re-excisions were evaluated using evRCM by a cutaneous surgeon, with retrospective review by an independent pathologist when results differed from histology.

RESULTS

evRCM demonstrated high specificity (0.96; 95% CI, 0.90-0.99) but low sensitivity (0.20; 95% CI, 0.06-0.51). Unlike pathology, which discards outer surgical margins, evRCM examined the true surgical margins. Retrospective pathology analysis of the misdiagnosed cases confirmed that 25% (n = 2/8) were false negative and 75% (n = 6/8) were potentially false positive, resulting in a sensitivity of 0.2-0.8. Notably, evRCM led to a 113-day reduction in in-hospital stays, probably resulting in increased patient satisfaction and cost-effectiveness.

CONCLUSIONS

evRCM was valuable for speeding up the assessment of surgical margins in patients with re-excised NMSC. Proper tissue preparation and assessment require interdisciplinary collaboration between cutaneous surgeons, pathologists, and physician assistants, emphasizing the need for standardized operating procedures.

Comparative Analysis of Inhibitory and Activating Immune Checkpoints PD-1, PD-L1, CD28, and CD86 in Non-Melanoma Skin Cancer

The establishment of immunotherapy applying immune checkpoint inhibitors (ICI) has provided an important new option for the treatment of solid malignant diseases. However, different tumor entities show dramatically different responses to this therapy. BCC responds worse to anti-PD-1 ICIs as compared to cSCC. Differential immune checkpoint expression could explain this discrepancy and, therefore, the aim of this study was to analyze activating and inhibitory immune checkpoints in cSCC and BCC tissues. Tissue microarrays of the invasive front as well as the tumor core of BCC and cSCC samples were used to evaluate PD-1, PD-L1, CD28, and CD86 expression and their topographic distribution profiles by chromogenic immunohistochemistry. QuPath was used to determine the labeling index. The expression of PD-1, PD-L1, and CD28 was significantly higher in both the tumor core and the invasive front of cSCC samples as compared to BCC (p < 0.001). In addition, the ratios of PD-L1/CD86 (p < 0.001) and CD28/CD86 (p < 0.001) were significantly higher in cSCC. The invasive front of both tumor entities showed higher expression levels of all immune markers compared to the tumor core in both tumor entities. The significantly higher expression of PD-1, PD-L1, and CD28 in cSCC, along with the predominance of the inhibitory ligand PD-L1 as compared to the activating CD86 in cSCC, provide a potential explanation for the better objective response rates to anti-PD-1 immunotherapy as compared to BCC. Furthermore, the predominant site of interaction between the immune system and the tumor was within the invasive front in both tumor types.

Cutaneous Squamous Cell Carcinoma: From Diagnosis to Follow-Up

Cutaneous squamous cell carcinoma (SCC) is the second most frequent skin cancer, accounting for approximately 20% of all cutaneous malignancies, and with an increasing incidence due to the progressive increment of the average age of life. The diagnosis is usually firstly suspected based on clinical manifestations; however, dermoscopic features may improve diagnostic sensitivity in cases of an uncertain diagnosis and may guide the biopsy, which should be performed to histopathologically prove the tumor. New diagnostic strategies may improve the sensitivity of the cutaneous SCC, such as reflectance confocal microscopy and line-field confocal optical coherence, for which increasing data have been recently published. Imaging has a central role in the staging of the diseases, while its exact role, as well as the choice of the best techniques, during the follow-up are not fully clarified. The aim of this literature review is to describe diagnostic clinical and instrumental tools of cutaneous SCC, with an insight into the role of imaging in the diagnosis and follow-up of cutaneous SCC.

Histological deep margins in cutaneous squamous cell carcinoma of the scalp and risk of recurrence

BACKGROUND

Consensus is lacking on adequate deep histological margins in cutaneous squamous cell carcinoma (cSCC). Deep clearance for tumours located on the scalp is limited by anatomic constraints.

OBJECTIVE

To determine whether clear but close deep histological margins (<1 mm) confer a higher risk of recurrence in cSCCs of the scalp treated by wide local excision, compared to deep histological margins ≥1 mm.

METHODS

Multicentre retrospective observational cohort study and multivariate competing risk analysis to evaluate risk factors for recurrence.

RESULTS

In total, 295 patients with 338 cSCCs were included. Close deep histological margins were not associated with an increased cumulative incidence of recurrence (subhazard ratio [SHR] 1.96 [95% CI 0.87-4.41]). However, an increased risk of recurrence was observed for those tumours that presented concurrent invasion of the galea aponeurotica and close deep margins, as opposed to patients without these factors (SHR 3.52 [1.24-10.01]). Tumours with clear but close peripheral margins (<1 mm) also had higher risk of recurrence (SHR 5.01 [1.68-14.97]).

LIMITATIONS

Retrospective observational study based on pathology reports.

CONCLUSION

Deep histological margins <1 mm do not confer a greater risk of recurrence as long as the tumour is completely excised and the galea aponeurotica is not involved. Surgical excision of cSCC on the scalp should include the galea to ensure proper assessment of deep margins.

Operational classification of cutaneous squamous cell carcinomas based on unsupervised clustering of real cases by experts

BACKGROUND

There is currently no staging system for cutaneous squamous cell carcinoma (cSCC) that is adapted to decision-making and universally used. Experts have unconscious ability to simplify the heterogeneity of clinical situations into a few relevant groups to drive their therapeutic decisions. Therefore, we have used unsupervised clustering of real cases by experts to generate an operational classification of cSCCs, an approach that was successful for basal cell carcinomas.

OBJECTIVE

To generate a consensual and operational classification of cSCCs.

METHOD

Unsupervised independent clustering of 248 cases of cSCCs considered difficult-to-treat. Eighteen international experts from different specialties classified these cases into what they considered homogeneous clusters useful for management, each with freedom regarding clustering criteria. Convergences and divergences between clustering were analysed using a similarity matrix, the K-mean approach and the average silhouette method. Mathematical modelling was used to look for the best consensual clustering. The operability of the derived classification was validated on 23 new practitioners.

RESULTS

Despite the high heterogeneity of the clinical cases, a mathematical consensus was observed. It was best represented by a partition into five clusters, which appeared a posteriori to describe different clinical scenarios. Applicability of this classification was shown by a good concordance (94%) in the allocation of cases between the new practitioners and the 18 experts. An additional group of easy-to-treat cSCC was included, resulting in a six-group final classification: easy-to-treat/complex to treat due to tumour and/or patient characteristics/multiple/locally advanced/regional disease/visceral metastases.

CONCLUSION

Given the methodology based on the convergence of unguided intuitive clustering of cases by experts, this new classification is relevant for clinical practice. It does not compete with staging systems, but they may complement each other, whether the objective is to select the best therapeutic approach in tumour boards or to design homogeneous groups for trials.

Molecular and Histopathological Characterization of Metastatic Cutaneous Squamous Cell Carcinomas: A Case-Control Study

BACKGROUND

A subset of patients affected by cutaneous squamous cell carcinoma (cSCC) can exhibit locally invasive or metastatic tumors. Different staging classification systems are currently in use for cSCC. However, precise patient risk stratification has yet to be reached in clinical practice. The study aims to identify specific histological and molecular parameters characterizing metastatic cSCC.

METHODS

Patients affected by metastatic and non-metastatic cSCC (controls) were included in the present study and matched for clinical and histological characteristics. Skin samples from primary tumors were revised for several histological parameters and also underwent gene expression profiling with a commercially available panel testing 770 different genes.

RESULTS

In total, 48 subjects were enrolled in the study (24 cases, 24 controls); 67 genes were found to be differentially expressed between metastatic and non-metastatic cSCC. Most such genes were involved in immune regulation, skin integrity, angiogenesis, cell migration and proliferation.

CONCLUSION

The combination of histological and molecular profiles of cSCCs allows the identification of features specific to metastatic cSCC, with potential implications for more precise patient risk stratification.

Efficacy of micrographic surgery versus conventional excision in reducing recurrence for basal cell carcinoma and squamous cell carcinoma: A systematic review and meta-analysis

The standard of care for basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) involves excision by conventional surgery (CS) with a predefined safety margin of resection or micrographic surgery (MS) with microscopic margin control. Previous studies have reported the superiority of MS in reducing recurrences for high-risk BCC and SCC. This systematic review aimed to assess MS and CS recurrence rates by including randomized clinical trials (RCTs) and cohort studies. A systematic review and meta-analysis were conducted for related studies in PubMed, LILACS, Embase, Scopus, Web of Science, CINHAL and Cochrane until May 2023. RCTs and cohorts involving patients with BCC or SCC submitted to MS and CS were included. Risk of bias assessment followed Cochrane-recommended tools for RCTs and cohorts, and certainty of evidence followed the GRADE approach. Pooled estimates were used to determine the relative risk (RR) and absolute risk difference (RD) using a random-effects model. Seventeen studies were included, two RCTs and fifteen cohorts. There were 82 recurrences in 3050 tumours submitted to MS, with an overall recurrence rate of 3.1% (95% CI 2.0%-4.7%). For CS, there were 209 recurrences in 3453 tumours, with a recurrence rate of 5.3% (95% CI 2.9%-9.3%). The combined estimate of RR was 0.48 (95% CI 0.36-0.63), without heterogeneity nor evidence of publication bias (p > 0.3). The RD resulted in 2.9% (95% CI 1.0%-4.9%; NNT = 35). Regarding subgroup analysis, the RR for BBC was 0.37 (95% CI 0.25-0.54), and RD was 3.7% (95% CI 0.8%-6.5%; NNT = 28). For SCC, RR was 0.57 (95% CI 0.29-1.13), and RD was 1.9% (95% CI 0.8%-4.7%; NNT = 53). Among primary tumours, RR was 0.39 (95% CI 0.28-0.54), and for recurrent tumours was 0.67 (95% CI 0.30-1.50). There is moderate evidence based on two RCTs, and low evidence based on 15 cohort studies that MS is superior to CS in reducing recurrences of BCCs and primary tumours. The development of protocols that maximize the cost-effectiveness of each method in different clinical scenarios is paramount.

Recent Changes in the Incidence and Characteristics of Cutaneous Squamous Cell Carcinomas in Finland from 2006 to 2020: A Retrospective Cohort Study

Registers recording only 1 tumour per patient do not enable assessment of the real burden of cutaneous squamous cell carcinoma. To investigate recent changes in the incidence and characteristics of tumours, a retrospective 15-year patient cohort study was performed in Finland. Histopathological diagnoses of cutaneous squamous cell carcinomas diagnosed between 2016 and 2020 were obtained from the pathology database and clinical data from patient medical records and combined with previously collected data for the years 2006-2015. Altogether 1,472 patients with 2,056 tumours were identified. The crude incidence increased from 19/100,000 persons in 2006 to 42 in 2020 (p < 0.001), increasing most in people aged over 80 years. The percentage of tumours located on the trunk increased from 5.3% during the first 5-year period, 2006-2010, to 9.0% in 2016-2020. Also, the location of tumours was significantly different between men and women, as men had more tumours on the scalp and ears, and women on the lower limbs. A slight change in the tumours from poorly to well differentiated and a decrease in the invasion depth were noted between 2006 and 2020. As the burden of tumours continues to increase, more attention should be paid to their prevention.

Long-term survival after anti-PD-1 discontinuation in advanced cutaneous squamous cell carcinoma (cSCC): a proof of concept of benefit of concomitant cemiplimab and radiotherapy

BACKGROUND

In a princeps study we conducted in patients with advanced cutaneous squamous cell carcinoma treated with concomitant anti-Programmed cell death protein 1 (PD-1) and radiotherapy, we demonstrated a clinico radiological response to cemiplimab that appeared to persist over time, 1 year after treatment discontinuation.

METHOD

We conducted a single-center descriptive study at Caen Hospital from September 1, 2021 to September 2023, in 14 patients with advanced carcinoma treated with cemiplimab until September 1, 2021. The aim of this update is to examine clinical and radiological follow-up 2 years after discontinuation of cemiplimab.

RESULTS

Of the 12 patients with a partial or complete response, we report 8 (66.7%) persistent responses 2 years after stopping cemiplimab, with only 2 patients progressing to distant disease, one lost to follow-up, and one death a priori unrelated to the disease.

CONCLUSION

Our study confirms a long-term and persistent effect despite discontinuation of cemiplimab at least up to 2 years later.

Electrochemotherapy as palliative care in patients with local or metastatic recurrence of head and neck cancer: review of state of the art

Head and neck cancers are mostly represented by squamous cell carcinoma. Despite effective treatment of primary tumours, local recurrences and metastases are frequent, with up to a 60% risk of local and 30% of distant failure. Moreover, second primary tumours sometimes occur in these patients (2-3% per year). Treatment of recurrences, metastases, and second primary tumours can be extremely challenging for Otorhinolaryngologists, especially in patients who have already been treated with radiotherapy, previous surgery, or both. Electrochemotherapy represents an effective and valid option in these cases.

Rationale for Using High-Frequency Ultrasound as a Routine Examination in Skin Cancer Surgery: A Practical Approach

Ultrasound and high-frequency ultrasound assessment of melanoma and non-melanoma skin cancer in the pre-therapeutical setting is becoming increasingly popular in the field of dermatosurgery and dermatooncology, as it can provide clinicians with relevant, "in vivo" parameters regarding tumor lateral and depth extension as well as potential locoregional spread, cancelling the need of more extensive imaging methods and avoiding a delay in diagnosis. Furthermore, preoperative sonography and color Doppler can aid in orienting the clinical diagnosis, being able in numerous situations to differentiate between benign and malignant lesions, which require a different therapeutic approach. This preoperative knowledge is of paramount importance for planning an individualized treatment regimen. Using sonography at the time of diagnosis, important surgical complications, such as neurovascular damage, can be avoided by performing a preoperative neurovascular mapping. Furthermore, sonography can help reduce the number of surgical steps by identifying the lesions' extent prior to surgery, but it can also spare unnecessary surgical interventions in cases of locally advanced lesions, which infiltrate the bone or already present with locoregional metastases, which usually require modern radiooncological therapies in accordance to European guidelines. With this review, we intend to summarize the current indications of sonography in the field of skin cancer surgery, which can help us improve the therapeutic attitude toward our patients and enhance patient counseling. In the era of modern systemic radiooncological therapies, sonography can help better select patients who qualify for surgical procedures or require systemic treatments due to tumoral extension.

Head and neck nonmelanoma skin cancers: surgical management and debated issues

PURPOSE OF REVIEW

This review critically assesses the current literature and guidelines, aiming to clarify some of the most important factors that impact surgical strategies of head and neck nonmelanoma skin cancers (NMSCs), focusing on squamous, basal, and Merkel cell carcinomas.

RECENT FINDINGS

Recent developments underscore the complexity of treatment for NMSC, particularly in the head and neck region. There is a lack of high-level evidence for the management of these tumors, especially in advanced stages. The need to tailor the extent of surgical margins and parotid/neck management to different histotypes, considering the varying risk factors for recurrence, is beginning to emerge in the literature. Moreover, the role of immunotherapy and targeted therapies for locally advanced disease, alongside traditional treatment options, is progressively growing.

SUMMARY

NMSCs represent a heterogeneous group of malignancies with varying treatment complexities and prognoses. Management of NMSC is evolving towards an increasingly personalized strategy within a multidisciplinary therapeutic framework.

Management of Cutaneous Squamous Cell Carcinoma of the Scalp: The Role of Imaging and Therapeutic Approaches

Cutaneous squamous cell carcinoma (cSCC) is the second most common subtype of skin cancer. The scalp is one of the most frequently affected locations and is associated with a higher rate of complications, compared to other locations. In addition, it has a characteristic thickness and anatomical structure that may influence both growth pattern and treatment of primary cSCC; while clinical peripheral margins may be easily achieved during the surgery, vertical excision of the tumor is limited by the skull. Despite having a unique anatomy, current guidelines do not contemplate specific recommendations for scalp cSCC, which leads to inconsistent decision-making in multidisciplinary committees when discussing tumors with high risk factors or with close margins. This article provides specific recommendations for the management of patients with scalp cSCC, based on current evidence, as well as those aspects in which evidence is lacking, pointing out possible future lines of research. Topics addressed include epidemiology, clinical presentation and diagnosis, imaging techniques, surgical and radiation treatments, systemic therapy for advanced cases, and follow-up. The primary focus of this review is on management of primary cSCC of the scalp with localized disease, although where relevant, some points about recurrent cSCCs or advanced disease cases are also discussed.

A Sub-Group of Kidney-Transplant Recipients with Highly Aggressive Squamous Cell Carcinoma Expressing Phosphorylated Serine392p53

Cutaneous squamous cell carcinomas in kidney-transplant recipients are frequent, with an increasing incidence linked to long immunosuppression durations and exposure to ultraviolet radiation. p53 is at the cornerstone of ultraviolet-induced DNA damage, but the role of p53 post-translational modifications in this context is not yet deciphered. Here, we investigated the phosphorylation status of p53 at Serine 392 in 25 cutaneous squamous cell carcinomas in kidney-transplant recipients, compared with 22 non-transplanted patients. Cutaneous squamous cell carcinomas in transplanted patients occurred after a median period of 19 years of immunosuppression, with a median number of 15 cutaneous squamous cell carcinomas and more aggressive histological and clinical characteristics. There was no significant difference between Ki67, p53, and pSer392p53 expression in the two groups. Using principal component analysis, we identified a cluster of exclusively transplanted patients with a median of 23 years of immunosuppression duration, significantly more aggressive biological characteristics, and higher pSer392p53 expression. pSer392p53 was expressed in the whole tumor, suggesting an early carcinogenic event in the course of prolonged immunosuppression. This high, diffuse pSer392p53 expression, corresponding to a high level of DNA damage, might be useful to identify aggressive cutaneous squamous cell carcinomas in kidney-transplant recipients to treat them more aggressively.