Postoperative radiotherapy provides better local control and long‐term outcome in selective cases of cutaneous squamous cell carcinoma with perineural invasion

Management Approaches for High-Risk Cutaneous Squamous Cell Carcinoma with Perineural Invasion: An Updated Review

OPINION STATEMENT

Cutaneous squamous cell carcinoma (cSCC) stands as the second most prevalent non-melanoma skin cancer worldwide, comprising approximately 20% of all cutaneous malignancies. Determining its precise incidence poses challenges; however, reports indicate a global increase in its prevalence. At the time of diagnosis, the majority of cSCCs are localized, resulting in favorable 5-year cure rates surpassing 90%. Nevertheless, a subset of patients (3-7%) encounters locally advanced or metastatic cSCC, leading to substantial morbidity and mortality. The risk of metastasis ranges from 0.1% to 9.9%, carrying an associated mortality risk of 2.8%. Factors influencing recurrence, metastasis, and disease-specific mortality underscore the significance of perineural invasion (PNI) as a key indicator. Patients with PNI may manifest clinical symptoms and/or radiologic signs of PNI, while the majority remain asymptomatic, and PNI is frequently identified upon histologic examination. Despite its lower frequency compared to other cancer types, PNI serves as a recognized adverse prognostic factor for cSCC. Surgery is the elective treatment for these patients, while the role of adjuvant radiotherapy (ART) is yet contentious and have not been conclusively assessed, particularly in clear surgical margin. Prospective comparative studies are required to comprehensively evaluate the benefit and the risks of ART for cSCC and PNI patients.

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.

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

In order to update recommendations on treatment, supportive care, education, and follow-up of patients with invasive cutaneous squamous cell carcinoma (cSCC), a multidisciplinary panel of experts from the European Association of Dermato-Oncology (EADO), the European Dermatology Forum (EDF), the European Society for Radiotherapy and Oncology (ESTRO), the European Union of Medical Specialists (UEMS), the European Academy of Dermatology and Venereology (EADV), and the European Organisation of Research and Treatment of Cancer (EORTC) was formed. Recommendations were based on an evidence-based literature review, guidelines, and expert consensus. Treatment recommendations are presented for common primary cSCC (low risk, high risk), locally advanced cSCC, regional metastatic cSCC (operable or inoperable), and distant metastatic cSCC. For common primary cSCC, the first-line treatment is surgical excision with postoperative margin assessment or micrographically controlled surgery. Achieving clear surgical margins is the most important treatment consideration for patients with cSCCs amenable to surgery. Regarding adjuvant radiotherapy for patients with high-risk localised cSCC with clear surgical margins, current evidence has not shown significant benefit for those with at least one high-risk factor. Radiotherapy should be considered as the primary treatment for non-surgical candidates/tumours. For cSCC with cytologically or histologically confirmed regional nodal metastasis, lymph node dissection is recommended. For patients with metastatic or locally advanced cSCC who are not candidates for curative surgery or radiotherapy, anti-PD-1 agents are the first-line systemic treatment, with cemiplimab being the first approved systemic agent for advanced cSCC by the Food and Drugs Administration/European Medicines Agency. Second-line systemic treatments for advanced cSCC, include epidermal growth factor receptor inhibitors (cetuximab) combined with chemotherapy or radiotherapy. Multidisciplinary board decisions are mandatory for all patients with advanced cSCC, considering the risks of toxicity, the age and frailty of patients, and co-morbidities, including immunosuppression. Patients should be engaged in informed, shared decision-making on management and be provided with the best supportive care to improve symptom management and quality of life. The frequency of follow-up visits and investigations for subsequent new cSCC depends on underlying risk characteristics.

New and emerging drugs for the treatment of advanced cutaneous squamous cell carcinoma

INTRODUCTION

Cutaneous squamous cell carcinoma (CSCC) is the second most common form of human cancer. Treatment of locally advanced and/or recurrent CSCC is often challenging. A subset of patients are not candidates for curative-intent therapies due to extent of loco-regional disease, refractoriness to prior local therapy, or presence of distant metastasis.

AREAS COVERED

Traditionally, CSCC has been treated with surgery and/or radiotherapy, but in some instances, local therapies can lead to significant functional morbidity or are no longer feasible. Until 2018, systemic therapy options to treat patients with advanced CSCC were limited. Recently, clinical studies have shown activity of Immune Checkpoint Inhibitors (ICI) in patients with advanced CSCC. This article reviews the current systemic therapy options for CSCC with a focus on ICI and emerging promising therapies in the treatment of this challenging disease.

EXPERT OPINION

ICI is currently the most effective and tolerable systemic therapy in the treatment of non-immunosuppressed advanced CSCC and can lead to cure in a subset of patients. Combinatorial therapies to overcome resistance to ICI may further increase the proportion of patients who will benefit from ICI and may help improve the quantity and quality of life of patients affected by this disease.

Recent Advances in Immunotherapy for Patients with Head and Neck Cutaneous Squamous Cell Carcinoma

Simple Summary

Cutaneous squamous cell cancer is a form of skin cancer, which is typically found in older fair-skinned individuals with frequent sun exposure. Most patients present with limited disease and can be treated with a combination of surgery and/or radiation with favorable outcomes. A small percentage of patients present with more aggressive, widespread disease. Immunotherapy has dramatically improved outcomes and has become the preferred treatment option for these patients. In this review article, the rationale for using immunotherapy in patients with squamous cell skin cancer is discussed. A summary of the new treatment options currently being explored is also provided.

Abstract

Cutaneous squamous cell carcinoma (CSCC) is the second most common non-melanoma skin cancer. A majority of patients present with localized disease, but some can present with locally advanced or metastatic disease. Most of these advanced cases occur in the anatomical head and neck region and are associated with more aggressive disease, necessitating prompt and effective treatment. Prior to the emergence of immunotherapy, systemic treatment options were limited to platinum-based chemotherapy and salvaged with targeted epidermal growth factor therapy. These therapies were associated with poor efficacy and increased toxicity in an often frail, older population. Immunotherapy has dramatically improved outcomes in this patient population due to its favorable side effect profile, durable treatment response, and improved overall outcomes. In this review, an overview of the recent advances of immunotherapy in the management of CSCC in the anatomical head and neck region is provided, with a focus on advanced presentations.

Recent Advances in the Diagnosis and Management of High-Risk Cutaneous Squamous Cell Carcinoma

High-risk cSCC is defined as invasive cSCC staged as N0 (without detectable regional lymph nodes) and M0 (without distant metastasis), that has features associated with a higher risk of poorer prognosis. The focus of this review is on the recent advances in the diagnosis and management of high-risk cSCC. The interest in high-risk cSCC relies on its higher risk of progression to advanced cSCC, as it represents the main pool of cSCCs that give rise to advanced tumors. Assessment of the risk is thus particularly relevant for common cSCC to identify the few with a high-risk risk of local recurrence, metastasis, or disease-specific death among all other low-risk tumors. The timely diagnosis and effective treatment of high-risk cSCCs may halt their further progression and aim to prevent and lower the incidence of advanced cSCCs. Clearance of the tumor with negative surgical margins is the main goal of surgery, which is the primary treatment of cSCC. It seems that it is difficult to discern the group of high-risk cSCCs that may benefit from adjuvant RT, as a universal beneficial effect for a cSCC with any high-risk factor which was resected with clear surgical margins has not been established. In the case of a high-risk cSCC with positive margins after surgery, and re-excision not feasible, post-operative radiotherapy is performed when possible. Recommendations on further management are discussed. Regarding the follow-up of patients diagnosed with high-risk cSCC, factors to consider regarding the frequency and intensity of the follow-up schedule include the risk and possible time of occurrence of metastasis from cSCC.

High-dose-rate plesiotherapy with customized molds in non-melanoma skin cancer: efficacy and safety at 10 years-single institution experience

PURPOSE

Our center adopted high-dose-rate brachytherapy with surface applicators (plesiotherapy) in 2008, creating custom molds to treat irregular areas. This study describes the efficacy and safety outcomes after extensive follow-up in the patients.

METHODS/PATIENTS

We planned the treatment using two computed tomography (CT) scans: the first to delineate the lesion and the second after placing the thermoplastic mold. Fusing the two CT images enables planning of the target volume and pinpointing, where the catheters are in the mold.

RESULTS

Seventy patients received plesiotherapy, either exclusively or following excision in patients with risk factors for recurrence. Those receiving plesiotherapy alone showed a complete response rate of 95.8%, and recurrences occurred in 5.7% at a mean follow-up of 96.2 months. Chronic toxicity appeared in 26.6% of patients, but severity was limited to grade 1 or 2.

CONCLUSIONS

High-dose-rate brachytherapy with customized molds yields a high rate of complete response, with long-term recurrence rates in line with similar studies and an acceptable toxicity rate.

Current Methods and Caveats to Risk Factor Assessment in Cutaneous Squamous Cell Carcinoma (cSCC): A Narrative Review

Cutaneous squamous cell carcinoma (cSCC) is the second most common form of skin cancer, and the number of deaths due to cSCC is estimated to be greater than the number attributed to melanoma. While the majority of cSCC tumors are resectable with clear margins by standard excision practices, some lesions exhibit high-risk factors for which there is evidence of their association with recurrence, metastasis, and disease-specific death. The most commonly used staging systems and guidelines in the USA for cSCC are based on these clinical and pathologic high-risk factors; however, these are limited in their ability to predict adverse events, thus posing a challenge for implementing risk-directed patient management. Since the development of local recurrence and/or metastasis has a profound impact on the survival of patients with cSCC, accurate identification of patients at high risk for poor outcomes is critical, potentially allowing for early and appropriate adjuvant therapy. This review summarizes the current cSCC literature with a focus on how differing clinical assessments within each of the five selected risk factors (perineural invasion, differentiation, depth of invasion, size, and location) can influence the evaluation of patient outcomes, along with summarizing the utility of staging and guidelines, and highlighting the potential for molecular tools to improve upon cSCC risk assessment.

Adjuvant radiotherapy may not significantly change outcomes in high-risk cutaneous squamous cell carcinomas with clear surgical margins: A systematic review and meta-analysis

BACKGROUND

The role of adjuvant radiotherapy for high-risk cutaneous squamous cell carcinomas (cSCC) after surgery with negative margins is unclear.

OBJECTIVE

To conduct a systematic review and meta-analysis examining the risk of poor outcomes for those treated with surgery vs. surgery and adjuvant radiotherapy.

METHODS

A comprehensive search of articles was executed in PubMed, Embase, and Cochrane Database. Random-effected meta-analyses were conducted.

RESULTS

Thirty-three studies comprised of 3,867 high-risk cSCC were included. There were no statistically significant differences in poor outcomes between the surgery vs. surgery and adjuvant radiotherapy groups. Estimates for local recurrence were 15.2% (95% confidence interval [CI]: 6.3%-27%) vs. 8.8% (CI: 1.6%-20.9%), regional metastases were 11.5% (CI: 7.2%-16.7%) vs. 4.4% (CI: 0%-18%), distant metastases were 2.6% (CI: 0.6%-6%) vs. 1.7% (CI: 0.2%-4.5%) and disease-specific deaths were 8.2% (CI: 1.2%-20.6%) vs. 19.7% (CI: 3.8%-43.7%) for the surgery group vs. surgery and adjuvant radiotherapy group respectively.

LIMITATIONS

Retrospective nature of most studies with a lack of sufficient patient-specific data.

CONCLUSIONS

For patients with high risk cSCC treated with margin-negative resection, there were no differences in poor outcomes between the surgery vs. surgery and adjuvant radiotherapy groups. Randomized-controlled trials are necessary to define the benefit of adjuvant radiotherapy in this setting.

A Systematic Review of Primary, Adjuvant, and Salvage Radiation Therapy for Cutaneous Squamous Cell Carcinoma

BACKGROUND

The gold standard of treatment for cutaneous squamous cell carcinoma (cSCC) is surgery radiation therapy (RT) is used selectively as definitive treatment for low-risk tumors or as adjuvant/salvage treatment for high-risk tumors. There is a lack of standardized studies evaluating the efficacy of RT in either clinical scenario.

OBJECTIVE

To determine the efficacy of primary and adjuvant/salvage RT for the treatment of cSCC.

MATERIALS AND METHODS

A systematic review of PubMed, Embase, Cochrane, and Web of Science was performed for studies that reported outcomes of cSCC treated with RT to the primary site alone. Outcomes included local control (LC), local recurrence (LR), nodal metastases (NM), distant metastases (DM), disease-specific death (DSD), and recurrence-free survival (RFS).

RESULTS

Forty-six studies with 4,141 tumors were included. Pooled LC and LR rates were 87.3% and 8.6%, respectively. The rates of NM, DM, DSD, and RFS were 4.8%, 3.5%, 5.3%, and 73.5%, respectively. Local recurrence was significantly higher for T3 and T4 tumors, with rates above 25.9%.

CONCLUSION

LR after RT to the primary site increased with increasing tumor stage, highlighting the importance of clear surgical margins for high-risk tumors. Prospective randomized studies characterizing outcomes by tumor stage for RT compared with surgery are needed to inform guidelines.

Efficacy and prognostic factors of adjuvant radiotherapy for cutaneous squamous cell carcinoma: A systematic review and meta-analysis

Although adjuvant radiotherapy has been used for cutaneous squamous cell carcinoma, its outcome benefits, especially for patients with clear surgical margins, have not been statistically estimated, and the characteristics that can indicate patients who require adjuvant therapy need to be validated with more evidence. We conducted a systematic review and meta-analysis of literature on the survival outcomes and prognostic factors in patients with cSCC treated by surgery with or without adjuvant radiotherapy. Twenty related studies involving 2605 patients met our inclusion criteria. The significant survival outcomes of adjuvant radiotherapy included lower recurrence (OR, 0.56; 95% CI, 0.36-0.85), longer disease-free survival (OR, 2.17; 95% CI, 1.23-3.83) and longer overall survival (OR, 2.94; 95% CI, 1.75-4.91). Significant prognostic factors for poor outcomes were perineural invasion (HR, 1.61; 95% CI, 1.24-2.09), involved surgical margins (HR, 2.34; 95% CI, 1.42-3.83) and immunosuppression (HR, 3.02; 95% CI, 2.14-4.25) while adjuvant radiotherapy significantly contributed to better overall survival (HR, 0.47; 95% CI, 0.34-0.65). In conclusion, this systematic review suggests that in cutaneous squamous cell carcinoma patients with risk factors, including metastasis to the parotid gland, perineural invasion and immunosuppression, the use of adjuvant radiotherapy may be beneficial irrespective of surgical margin status.