High-Risk Cutaneous Squamous Cell Cancer of the Head and Neck: Risk Factors for Recurrence and Impact of Adjuvant Treatment

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.

Cutaneous Squamous Cell Carcinoma: An Updated Review

Representing the second most common skin cancer, the incidence and disease burden of cutaneous squamous cell carcinoma (cSCC) continues to increase. Surgical excision of the primary site effectively cures the majority of cSCC cases. However, an aggressive subset of cSCC persists with clinicopathological features that are indicative of higher recurrence, metastasis, and mortality risks. Acceleration of these features is driven by a combination of genetic and environmental factors. The past several years have seen remarkable progress in shaping the treatment landscape for advanced cSCC. Risk stratification and clinical management is a top priority. This review provides an overview of the current perspectives on cSCC with a focus on staging, treatment, and maintenance strategies, along with future research directions.

Lymphovascular Invasion in Cutaneous Squamous Cell Carcinoma

BACKGROUND

Although there is a large body of literature regarding risk stratification and outcomes for perineural invasion (PNI) in cutaneous squamous cell carcinoma (cSCC), there is a relative paucity of studies exploring the role of lymphovascular invasion (LVI) in cSCC and a lack of clear evidence-based guidelines for how to manage patients with these tumors.

OBJECTIVE

This article is intended to review the available literature regarding LVI in cSCC and formulate evidence-based recommendations for clinical management.

METHODS AND MATERIALS

A literature review was conducted using PubMed to find relevant articles relating to outcomes and management of primary cSCC with LVI.

RESULTS

The available literature suggests that LVI is a major risk factor for poor outcomes and increased morbidity and mortality in cSCC.

CONCLUSION

Lymphovascular invasion is a very high-risk feature that should place these tumors in the highest-risk category, and management of these tumors should be similar to that of squamous cell carcinoma with PNI.

Impact of the COVID-19 Pandemic on the Diagnosis and Management of Non-Melanoma Skin Cancer in the Head and Neck Region: A Retrospective Cohort Study

The present study investigates the impact of the COVID-19 pandemic on the management of Non-Melanoma Skin Cancer (NMSC) in the head and neck region. Conducted at the University Hospital "Le Scotte" in Siena, Italy, the research includes 111 patients treated from 2018 to 2021. The study aims to understand how pandemic-related healthcare changes affected NMSC treatment, focusing on differences in diagnosis and management before and during the pandemic. Methods involved retrospective analysis of patient demographics, clinical characteristics, lesion details, and treatment modalities, using Jamovi software (version 1.6) for statistical analysis. Results revealed the scalp as the most common NMSC site, with Squamous Cell Carcinoma (SCC) being the predominant histotype. A significant rise in Basal Cell Carcinoma (BCC) cases and a reduction in surgery duration were noted during the pandemic. The shift to local anesthesia was more pronounced, reflecting the necessity to adapt to healthcare limitations. Despite the disruptions caused by the pandemic, there was no significant drop in NMSC cases, which is attributed to the noticeable nature of head and neck lesions. In conclusion, this study highlights that the COVID-19 pandemic significantly influenced surgical practices in NMSC management, emphasizing the need for effective healthcare strategies that balance quality patient care with public health safety measures.

Recommendations for risk stratification of periocular squamous cell carcinoma

Periocular squamous cell carcinoma is a common cutaneous malignancy with generally favorable outcomes; however, the periocular region is intrinsically a high-risk location, and there exist a subset of lesions with a propensity for poor outcomes. Orbital invasion, intracranial perineural spread, nodal and distant metastasis are feared complications. There are several staging systems for eyelid carcinoma and cutaneous squamous cell carcinoma, but the definition of high-risk lesions remains heterogeneous. It is unclear exactly which lesions can be safely deescalated, and which require nodal evaluation and adjuvant multimodal therapy. We seek to answer these questions by summarizing the literature on clinicopathologic variables, molecular markers, and gene profiling tests in periocular squamous cell carcinoma, with the extrapolation of data from the cutaneous squamous cell carcinoma literature. Standardized pathology reports with information on tumor dimensions, histological subtype and grade, perineural invasion, and lymphovascular invasion should become uniform. Integration with gene expression profiling assessments will individualize and improve the predictive accuracy of risk stratification tools to ultimately inform multidisciplinary decision-making.

Radiotherapy for cutaneous squamous cell carcinoma: current standards and outlooks

Cutaneous squamous cell carcinoma accounts for 20 % of all malignant non-melanoma skin tumors, which is one of the most common cancers worldwide. Antitumor treatment is usually very effective: cure rate reaches 90 %, while local recurrence rate is 25 %. The main treatment option for primary skin cancers is surgery. The most significant risk factors for locoregional recurrence include tumor location (head and neck), size (>2 cm), depth of invasion (>4 mm), tumor differentiation grade, perineural invasion, immune system disorders (immunosuppression), severe concomitant diseases, and previous treatment.

In patients with advanced cutaneous squamous cell carcinoma, 1-year, 2-year, and 3-year survival rates are 50–80, 30–35 and 15–16 %, respectively. Radiotherapy is a radical treatment option that increases the 5-year survival rate to 90 % and ensures good cosmetic results in 80 % of cases. There are 3 main variants of radiotherapy for cutaneous squamous cell carcinoma: sole radiotherapy according to a radical program, adjuvant radiotherapy in combination with surgery, and palliative radiotherapy. most frequently, radiotherapy is used as part of adjuvant postoperative treatment and is not initially considered as a sole conservative treatment for cutaneous squamous cell carcinoma patients below 45 years of age with resectable tumors, especially high-risk tumors. palliative radiotherapy is an affordable and effective method for combating painful symptoms; moreover, it often provides long-term local control. 

Perineural invasion and perineural spread in periocular squamous cell carcinoma

Perineural invasion (PNI) in cutaneous squamous cell carcinoma (SCC) of the periocular region is a prognostic marker of adverse tumour outcomes. PNI carries a well-established risk of tumour recurrence, regional metastasis and higher likelihood of mortality. This review will explore and stratify the risks conferred by histological PNI parameters. The radiological features of perineural spread (PNS) and the imaging sequences that delineate these findings will also be highlighted. Surgical excision with en face margin control is the preferred technique for achieving histological clearance. Adjuvant radiotherapy improves treatment outcomes in the setting of concomitant high-risk features. For locally advanced or metastatic cutaneous SCC, immunotherapy represents a novel treatment alternative. This review will provide an algorithm for the diagnosis and management of periocular SCC with PNI and PNS.

Advances in Cutaneous Squamous Cell Carcinoma Management

Simple Summary

Cutaneous squamous cell carcinoma (cSCC) is an increasingly prevalent and morbid cancer worldwide. Management of this cancer has changed significantly in the last decade through improved risk stratification and new therapies offering patients with locally advanced and metastatic disease more effective, less toxic, and more durable treatment options. Ongoing clinical trials are assessing new therapeutic options as well as optimizing existing regimens in efforts to better manage this cancer. The recent developments highlight the need for multidisciplinary care, especially for those with locally advanced and metastatic disease.

Abstract

cSCC is increasing in prevalence due to increased lifespans and improvements in survival for conditions that increase the risk of cSCC. The absolute mortality of cSCC exceeds melanoma in the United States and approaches that of melanoma worldwide. This review presents significant changes in the management of cSCC, focusing on improvements in risk stratification, new treatment options, optimization of existing treatments, and prevention strategies. One major breakthrough in cSCC treatment is the advent of immune checkpoint inhibitors (ICIs) targeting programmed cell death protein 1 (PD-1) and programmed death-ligand 1 (PD-L1), which have ushered in a renaissance in the treatment of patients with locally advanced and metastatic disease. These agents have offered patients with advanced disease decreased therapeutic toxicity compared to traditional chemotherapy agents, a more durable response after discontinuation, and improved survival. cSCC is an active field of research, and this review will highlight some of the novel and more developed clinical trials that are likely to impact cSCC management in the near future.

Advanced or Metastatic Cutaneous Squamous Cell Carcinoma: The Current and Future Role of Radiation Therapy in the Era of Immunotherapy

Simple Summary

Nodal and distant metastases of cutaneous squamous cell carcinomas are very rare and lead to dismal prognoses. Immunotherapy is approved only for cutaneous squamous cell carcinoma patients not amenable to surgery or curative radiation therapy. Radiation therapy has a clear role as an adjuvant treatment for locally advanced disease. Radiation therapy may also have an important role in inoperable and metastatic disease. Oligometastatic disease is a condition that needs to be defined for this carcinoma. This review aims to offer to the readers a comprehensive overview of studies about the role of radiotherapy in the management of advanced or metastatic cutaneous squamous cell carcinomas, also assuming possible further developments in the light of the recent discoveries about tumor biology. The present paper has the merit of re-focusing great attention on the efficacy and cost-effectiveness of radiotherapy in these not yet properly explored scenarios.

Abstract

Radiation therapy (RT) is an effective therapeutic option for small localized cutaneous squamous cell carcinoma (cSCC) among patients who are not eligible for or refuse surgery. RT also has a defined role as an adjuvant treatment in cases of adverse features that predispose to tumor recurrence after local excision. Since the development of cSCC is often a late consequence of chronic sun exposure, its occurrence is more common among elderly patients whose comorbidities may contraindicate surgical procedures. These could be impeded not only by frail medical conditions but also by technical issues. Indeed, an aggressive locoregional behavior of cSCC may culminate in unresectability due to widespread invasion of neighboring tissues. Moreover, cSCC could develop distant metastases. Both locally advanced and metastatic cSCCs carry a poor prognosis. In these scenarios, recent discoveries of tumor molecular targets are promoting the use of promising systemic therapies, especially immunotherapy, over RT. However, the results from using immunotherapy and, even more so, of chemotherapy are still not optimal. By contrast, advances in radiation delivery equipment can safely treat even large and complex-shaped cSCC targets in challenging body sites. In addition, RT could also have a role in metastatic cSCC settings by enhancing the effectiveness of concomitant immunotherapy. The aim of this review is to summarize and comment on the body of literature about the use of radiotherapy for operable and inoperable locally advanced cSCCs and for metastatic ones in an attempt to define its current and future role.

Redefining Perineural Invasion in Head and Neck Cutaneous Squamous Cell Carcinoma

OBJECTIVE

Perineural invasion (PNI) negatively affects disease-specific survival in patients with head and neck cutaneous squamous cell carcinoma (HNcSCC). We aim to analyze the prognostic implications of PNI-related features.

STUDY DESIGN

Retrospective cohort study.

SETTING

Academic tertiary care hospital.

METHODS

Retrospective chart review was performed on 104 patients diagnosed with HNcSCC between January 2011 and October 2019 who underwent resection, parotidectomy, and neck dissection with more than 1 year of follow-up. PNI was classified as incidental (identified on histopathology alone) or clinical (present on radiography and/or physical exam). Primary outcome measures were overall survival and disease-free survival (DFS). Kaplan-Meier analysis, logistic regression, and Cox regression were performed.

RESULTS

The overall 5-year DFS was 57.9%. Sixty-one patients had PNI. On histopathology, 28 lesions showed complete nerve encirclement, 10 involved >5 nerves, and 12 involved named nerves. Patients with facial weakness (P = .026) and positive margins (P = .0029) had a higher likelihood of histopathologic PNI, and positive margins retained significance on multivariable analysis (P = .0079). Worse DFS was seen in patients with PNI (P = .004), advanced tumor stage (P = .049), positive margins (P = .014), and >5 nerves involved (P = .0061). Furthermore, histopathologic PNI was a predictor of DFS (hazard ratio [HR], 3.07; 95% CI, 0.33-1.38; P = .0061) overall and in the clinical PNI cohort (HR, 3.43; 95% CI, 1.65-7.10; P = .00091).

CONCLUSION

DFS was significantly worse in patients with PNI, facial nerve weakness, advanced T stage, positive margins, and multiple nerve involvement. Further characterization of PNI features may help improve prognostic predictions and identify patients who may benefit from more aggressive treatment.

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.

Risk Factors and Diagnosis of Advanced Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the second most common cancer affecting humans. The combination of the increasing incidence and high mortality in advanced stages of the disease, defines cSCC as an emerging public health problem. Advanced disease includes metastatic and locally advanced cSCC. Metastatic disease refers to the presence of locoregional metastasis (in transit or to regional lymph nodes) or distant metastasis. Locally advanced disease has been defined as non-metastatic cSCC that is unlikely to be cured with surgery, radiotherapy, or combination treatment. While metastatic cSCC is easily diagnosed, locally advanced disease lacks consensus definition and diagnosis is made after multidisciplinary board consultation. Identifying patients with aggressive cSCC at highest risk for relapse may prevent the occurrence of advanced disease. Prognostic factors suggested by most guidelines include tumor diameter (>2 cm), localization on temple/ear/lip/area, thickness (>6 mm), or invasion beyond subcutaneous fat, poor grade of differentiation, desmoplasia, perineural invasion, bone erosion, immunosuppression, undefined borders, recurrence, growth rate, site of prior radiotherapy, and lymphatic or vascular involvement. Although risk factors associated with worse outcomes are well known, there is still a gap of knowledge on the precise risk of each factor taken individually. The aim of this review is to summarize cSCC prognostic factors and encompass the various staging systems to guide management and follow-up in cSCC patients at higher risk for local recurrence and metastasis. Finally, we describe the hallmarks of the advanced disease. Advanced cSCC diagnosis should be made by a multidisciplinary board considering patients' performance status and disease characteristics.

Elective neck dissection versus observation in patients with head and neck cutaneous squamous cell carcinoma

BACKGROUND

The survival benefit of elective neck dissection (END) for patients with cutaneous squamous cell carcinoma (cSCC) of the head and neck and no evidence of regional metastasis (cN0) has never been reported. The aim of this study was to determine the effect of END on patient survival.

METHODS

The authors included patients with head and neck cSCC who had undergone primary surgery from 1995 to 2017. The primary end point was survival, and the secondary end points were the incidence of occult regional disease and regional disease control. To assess the impact of END on survival, the authors used multivariable Cox proportional hazards models with propensity score and matching techniques for internal validation.

RESULTS

A total of 1111 patients presented with no evidence of nodal disease; 173 had END, and 938 were observed. Adjuvant radiotherapy to the neck was administered to 101 patients (9%). END resulted in a 5-year overall survival rate of 52%, whereas the rate was 63% in the observation group (P = .003 [log-rank]). The 5-year disease-free survival rate for patients undergoing END was similar to that for the observation group (73% vs 75%; P = .429). A multivariate regression model showed that the performance of END was not associated with improved rates of overall, disease-specific, or disease-free survival; similarly, among patients with advanced disease (T3-4), those who underwent END did not have improved survival rates.

CONCLUSIONS

Among patients with cSCC of the head and neck, observation of the neck nodes resulted in noninferior survival rates in comparison with END at the time of primary surgery. Further studies are required to elucidate the role of END in patients with advanced disease.

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.