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.

Comparative Analysis of US Guidelines for the Management of Cutaneous Squamous Cell and Basal Cell Carcinoma

Background

This study presents a comparative analysis of recently published guidelines to manage cutaneous squamous cell carcinoma (cSCC) and cutaneous basal cell carcinoma (cBCC) within the United States (US).

Methods

A PubMed database search was performed for the time period between June 1, 2016, and December 1, 2022. A comprehensive comparison was performed in the following clinical interest areas: staging and risk stratification, management of primary tumor and regional nodes with curative intent, and palliative treatment.

Results

Guidelines from 3 organizations were analyzed: the American Academy of Dermatology (AAD), the National Comprehensive Cancer Network (NCCN), and the American Society for Radiation Oncology (ASTRO). The guidelines used different methodologies to grade evidence, making comparison difficult. There was agreement that surgery is the preferred treatment for curative cBCC and cSCC. For patients ineligible for surgery, there was a consensus to recommend definitive radiation. AAD and NCCN recommended consideration of other topical modalities in selected low-risk cBCC. Postoperative radiation therapy (PORT) was uniformly recommended in patients with positive margins that could not be cleared with surgery and in patients with nerve invasion. The definition and extent of nerve invasion varied. All guidelines recommended surgery as the primary treatment in patients with lymph node metastases in a curative setting. The criteria used for PORT varied; NCCN and ASTRO used lymph node size, number of nodes, and extracapsular extension for recommending PORT. Both NCCN and ASTRO recommend consideration of systemic treatment along with PORT in patients with extracapsular extension. Conclusion: US guidelines provide contemporary and complementary information on the management of cBCC and cSCC. There are opportunities for research, particularly in the areas of staging, indications for adjuvant treatment in curative settings, extent of nerve invasion and prognosis, and the role of systemic treatments in curative and palliative settings.

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.

Local Tumor Infiltration and Locoregional Recurrence in Desmoplastic Cutaneous Squamous Cell Carcinoma

BACKGROUND

Perusal of the literature of cutaneous squamous cell carcinoma (SCC) reveals that the role of the desmoplastic subtype is indistinct. Data on local infiltration and recurrence are inconsistent dependent on surgical technique, histological method, and investigated collective.

OBJECTIVE

The aim of the study was to analyze local infiltration and locoregional recurrence of the desmoplastic subtype under a uniform procedure.

METHODS AND MATERIALS

Between 2005 and 2015, 320 SCCs were analyzed and histological sections of all tumors were examined. Data collection included locoregional recurrence, metastasis rate, and tumor-specific death. The median follow-up was 36.5 months.

RESULTS

The desmoplastic subtype required significant more re-excisions (70.0% vs 23.9%, p < .001), more interventions until tumor-free margins were achieved (maximal 6 vs 2; p < .001), showed more widespread tumor infiltration with larger excisional margins (median 9 mm, 2-51 mm vs median 4 mm, 1-10 mm; p < .001), and a 5-fold higher local recurrence rate (26.7% vs 5.0%, p < .001). The metastasis rate (16.6% vs 2.3%, p < .001) was increased.

CONCLUSION

The desmoplastic subtype is characterized by a widespread local infiltration associated with perineural infiltration. It seems to be a marker for decreased histological detectability with a high rate of locoregional recurrence and metastasis.

Current Surgical Therapy of Locally Advanced cSCC: From Patient Selection to Microsurgical Tissue Transplant. Review

Among the non-melanoma skin cancers (NMSC) the squamous cell carcinoma (SCC) is one of the most challenging for the surgeon. Local aggressiveness and a tendency to metastasize to regional lymph nodes characterize the biologic behavior. The variants locally advanced and metastatic require wide excision and node dissection. Such procedures can be extremely detrimental for patients. The limit of the surgery can be safely pushed forward with a multidisciplinary approach. The concept of skin oncoplastic surgery, the ablative procedures and the reconstructive options (skin graft, pedicled flap, microsurgical free flap) are discussed together with a literature review.

Cutaneous Squamous Cell Carcinoma: From Pathophysiology to Novel Therapeutic Approaches

Cutaneous squamous cell carcinoma (cSCC), a non-melanoma skin cancer, is a keratinocyte carcinoma representing one of the most common cancers with an increasing incidence. cSCC could be in situ (e.g., Bowen's disease) or an invasive form. A significant cSCC risk factor is advanced age, together with cumulative sun exposure, fair skin, prolonged immunosuppression, and previous skin cancer diagnoses. Although most cSCCs can be treated by surgery, a fraction of them recur and metastasize, leading to death. cSCC could arise de novo or be the result of a progression of the actinic keratosis, an in situ carcinoma. The multistage process of cSCC development and progression is characterized by mutations in the genes involved in epidermal homeostasis and by several alterations, such as epigenetic modifications, viral infections, or microenvironmental changes. Thus, cSCC development is a gradual process with several histological- and pathological-defined stages. Dermoscopy and reflectance confocal microscopy enhanced the diagnostic accuracy of cSCC. Surgical excision is the first-line treatment for invasive cSCC. Moreover, radiotherapy may be considered as a primary treatment in patients not candidates for surgery. Extensive studies of cSCC pathogenic mechanisms identified several pharmaceutical targets and allowed the development of new systemic therapies, including immunotherapy with immune checkpoint inhibitors, such as Cemiplimab, and epidermal growth factor receptor inhibitors for metastatic and locally advanced cSCC. Furthermore, the implementation of prevention measures has been useful in patient management.

Comparison of guidelines for the management of patients with high-risk and advanced cutaneous squamous cell carcinoma - a systematic review

The management of high-risk cutaneous squamous cell carcinoma (cSCC) can be a challenge as evidence from high quality clinical trials is rare. Guideline developers are challenged to provide practical and useful guidance for clinicians even in the absence of good evidence. In order to compare treatment recommendations for high-risk and advanced cSCC among national and international guidelines and to extract the most precise guidance provided, a systematic search was carried out in guideline databases Medline and Embase with a cutoff of 4 March 2019. Treatment recommendations for predefined clinical scenarios were extracted from selected guidelines and compared qualitatively. Five guidelines published from 2015 to 2018 were included. Excision of high-risk tumours with margin assessment was recommended in all guidelines. A safety margin of at least 6 mm was suggested in four guidelines. There was no clear recommendation to perform a sentinel lymph node biopsy in any guideline. Lymph node dissection was uniformly recommended in the presence of nodal disease. Treatment for metastatic cSCC was poorly characterized and restricted to the use of chemotherapy and epidermal growth factor receptor inhibitors. Recommendations for the management of high-risk and advanced cSCC were limited. We propose that guidelines should be updated to reflect recent advances in checkpoint blockade for metastatic cSCC.

Prognostic Impact of Perineural Invasion in Cutaneous Squamous Cell Carcinoma: Results of a Prospective Study of 1,399 Tumors

Perineural infiltration (PNI) and desmoplasia are believed to be high-risk factors in the prognosis of squamous cell carcinoma (SCC). In the literature, dependences between PNI, de-differentiation, and desmoplasia remain unclear. The aim of this study was to analyze the respective prognostic impact of these factors in regard to local recurrence and metastasis. Between 2005 and 2015, 1,399 unselected primary SCCs of 1,434 patients were diagnosed. If a patient had multiple tumors, the tumor with the highest risk profile was selected. Histological sections of all tumors with a tumor thickness of ≥6 mm and desmoplastic SCC with a tumor thickness of 2.1-5.9 mm were re-examined for PNI. Median follow-up was 36.5 months. PNI was present exclusively within tumors of the desmoplastic type (14.5%). PNI was present significantly more often in patients developing lymph node metastasis (3% all non-desmoplastic SCC, 17% desmoplastic SCC, and 29% desmoplastic SCC with PNI) and local recurrence (3%, 26%, and 64%) and associated with overall tumor-specific death (4%, 25%, and 54%). Using a multivariate model of disease recurrence, tumor thickness ≥6 mm, tumor horizontal size ≥20 mm, immunosuppression, desmoplasia, and PNI remained significant factors. In conclusion, PNI was found to be an additional marker indicative of an unfavorable prognosis and an independent high-risk factor within the desmoplastic type of SCC.

European interdisciplinary guideline on invasive squamous cell carcinoma of the skin: Part 2. Treatment

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 Dermatology Forum, the European Association of Dermato-Oncology and the European Organization of Research and Treatment of Cancer was formed. Recommendations were based on 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 most frequent cSCC type), first-line treatment is surgical excision with postoperative margin assessment or microscopically controlled sugery. Safety margins containing clinical normal-appearing tissue around the tumour during surgical excision and negative margins as reported in the pathology report are necessary to minimise the risk of local recurrence and metastasis. In case of positive margins, a re-excision shall be done, for operable cases. Lymph node dissection is recommended for cSCC with cytologically or histologically confirmed regional nodal involvement. Radiotherapy should be considered as curative treatment for inoperable cSCC, or for non-surgical candidates. Anti-PD-1 antibodies are the first-line systemic treatment for patients with metastatic or locally advanced cSCC who are not candidates for curative surgery or radiation, with cemiplimab being the first approved systemic agent for advanced cSCC by the Food and Drug Administration/European Medicines Agency. Second-line systemic treatments for advanced cSCC include epidermal growth factor receptor inhibitors (cetuximab) combined with chemotherapy or radiation therapy. Multidisciplinary board decisions are mandatory for all patients with advanced disease who require more than surgery. Patients should be engaged with informed decisions on management and be provided with best supportive care to optimise symptom management and improve quality of life. Frequency of follow-up visits and investigations for subsequent new cSCC depend on underlying risk characteristics.

Anti-proliferative and pro-apoptotic effects of Uncaria tomentosa aqueous extract in squamous carcinoma cells

Uncaria tomentosa (Willd.) DC. (Rubiacee), also known as uña de gato, is a plant that grows wild in the upper Amazon region of Peru and has been widely used in folk medicine to treat several health conditions including cancer. We have produced an aqueous extract from Uncaria tomentosa (UT-ex) and analyzed its effects on squamous carcinoma cells and immortalized HaCaT keratinocytes. Squamous cell carcinoma (SCC) is an uncontrolled growth of abnormal cells arising in the skin's squamous layer of epidermis. When detected at an early stage, SCCs are almost curable, however, if left untreated, they can penetrate the underlying tissue and become disfiguring. We have evaluated cell proliferation, apoptosis and the level of reactive oxygen species following UT-ex treatment. UT-ex affected cell cycle progression and reduced cell viability in a dose and time-dependent manner. From a mechanistic point of view, this delay in cell growth coincided with the increase of reactive oxygen species (ROS). Furthermore, PARP1 cleavage was associated to the reduction of Y-box binding protein 1 (YB-1) 36kDa, a nuclear prosurvival factor involved in DNA damage repair. These data indicate that UT-ex-induced cell death can be ascribed, at least in part, to its ability both to induce oxidative DNA damage and antagonize the mechanism of DNA repair relying upon YB-1 activity. They also show that non metastatic SCCs are more susceptible to UT-ex treatment than untransformed keratinocytes supporting the use of UT-ex for the treatment of precancerous and early forms of squamous cell carcinomas. Preliminary chemical investigation of UT-ex revealed the presence of hydrophilic low-medium molecular weight metabolites with anticancer potential towards squamous carcinoma cells.

Antimicrobial peptide LL-37 promotes the viability and invasion of skin squamous cell carcinoma by upregulating YB-1

Antimicrobial peptide LL-37 serves a function in the host defense against microbial invasion, and also regulates cell proliferation, immune activity and angiogenesis. Previous studies have reported that LL-37 participates in the development of numerous tumour types, such as ovarian cancer, lung cancer, melanoma and breast cancer. However, the function of LL-37 in the development of skin squamous cell carcinoma (SCC) has not yet been fully elucidated. The aim of the current study was to investigate how LL-37 promotes the expression of Y-box binding protein 1 (YB-1) in SCC. Short interfering RNA (siRNA) was used to inhibit the expression of YB-1, and in vitro MTT and Transwell migration assays were used to evaluate the effect of reduced YB-1 on the viability and invasion of A431 cells. A431 cells were stimulated with LL-37, and quantitative polymerase chain reaction, immunofluorescence and western blot analyses were used to detect changes in YB-1 expression. Mitogen-activated protein kinase kinase, mitogen-activated protein kinase and nuclear factor (NF)-κB signaling pathway inhibitors were also used to evaluate the mechanism of LL-37-induced YB-1 protein expression. It was found that YB-1 expression was increased in SCC tissue compared with normal tissue. Inhibiting YB-1 expression using siRNA significantly reduced the viability and suppressed the invasion of tumour cells (P<0.05 for both). LL-37 treatment at 0.05 µg/ml for 24 or 48 h significantly promoted YB-1 protein expression (P<0.05), and this was dependent on the NF-κB signaling pathway. In conclusion, the current study demonstrated that by upregulating the expression of YB-1, LL-37 can promote the occurrence and development of SCC, and this process involves the NF-κB signaling pathway.

Antimicrobial peptide LL-37 promotes the proliferation and invasion of skin squamous cell carcinoma by upregulating DNA-binding protein A

The antimicrobial peptide LL-37 not only contributes to the host defence against microbial invasion but also regulates immune activity, angiogenesis and cell proliferation. Studies have shown that LL-37 participates in the development of a variety of tumours, such as lung cancer, ovarian cancer, breast cancer and melanoma. However, the role of LL-37 in the development of skin squamous cell carcinoma (SCC) is not clear. The present study used immunohistochemistry to confirm that the expression of human DNA-binding protein A (dbpA) was increased in SCC tissues. After stimulating SCC A341 cells, LL-37 was shown promote the proliferation, migration and invasion of these malignant cells. LL-37 also promoted the upregulation of dbpA mRNA and protein expression. In addition, after using small interfering RNA to silence the normal dbpA expression in these malignant cells, the proliferation and invasion of the tumor cells were significantly reduced. When the NF-κB inhibitor PDTC was used to inhibit the process of LL-37-stimulated cells, it was found that the original upregulated expression of dbpA was downregulated. Overall, the present demonstrated that by upregulating the expression of dbpA, LL-37 can promote the proliferation and invasion of tumour cells, and that this process depends on the NF-κB signalling pathway.

Non-melanoma Skin Cancer in Canada Chapter 3: Management of Actinic Keratoses

Background

Actinic keratosis (AK) and cheilitis (AC) are lesions that develop on photodamaged skin and may progress to form invasive squamous cell carcinomas (SCCs).

Objective

To provide guidance to Canadian health care practitioners regarding management of AKs and ACs.

Methods

Literature searches and development of graded recommendations were carried out as discussed in the accompanying introduction (chapter 1 of the NMSC guidelines).

Results

Treatment of AKs allows for secondary prevention of skin cancer in sun-damaged skin. Because it is impossible to predict whether a given AK will regress, persist, or progress, AKs should ideally be treated. This chapter discusses options for the management of AKs and ACs.

Conclusions

Treatment options include surgical removal, topical treatment, and photodynamic therapy. Combined modalities may be used in case of inadequate response. AKs are particularly common following the longterm immunosuppression in organ transplant patients, who should be monitored frequently to identify emerging lesions that require surgery.

Non-melanoma Skin Cancer in Canada Chapter 1: Introduction to the Guidelines

BACKGROUND

Non-melanoma skin cancer (NMSC), including basal and squamous cell carcinoma, represents the most common malignancy.

OBJECTIVE

The aim of this document is to provide guidance to Canadian health care practitioners on NMSC management.

METHODS

After conducting a literature review, the group developed recommendations for prevention, management, and treatment of basal cell carcinomas, squamous cell carcinomas, and actinic keratoses. These tumour types are considered separately in the accompanying articles. The Grading of Recommendations Assessment, Development and Evaluation system was used to assign strength to each recommendation.

RESULTS

This introduction describes the scope and structure of the guidelines and the methods used to develop them. The epidemiology of NMSC is reviewed, as are the pathophysiologic changes occurring with damage to the skin, which lead to the formation of actinic keratoses and invasive squamous or basal cell carcinomas.

CONCLUSIONS

This introduction describes the need for primary prevention and offers an overview of treatment options that are discussed in later chapters of the guidelines.

Non-melanoma Skin Cancer in Canada Chapter 4: Management of Basal Cell Carcinoma

Background

Basal cell carcinoma (BCC) is the most common malignancy. Growth of BCCs leads to local destruction of neighbouring healthy skin and underlying tissue and can result in significant functional and cosmetic morbidity.

Objective

To provide guidance to Canadian health care practitioners regarding management of BCCs.

Methods

Literature searches and development of graded recommendations were carried out as discussed in the accompanying Introduction.

Results

Although BCCs rarely metastasize“ they can be aggressive and disfiguring. This chapter describes the natural history and prognosis of BCCs. Risk stratification is based on clinical features” including the site and size of the tumour“ its histologic subtype (nodular vs sclerosing)” and its history of recurrence.

Conclusions

Various options should be considered for BCC treatment” including cryosurgery” curettage” and topical or photodynamic approaches, as well as fixed-margin surgery and Mohs micrographic surgery. Stratification of recurrence risk for individual BCCs determines the most appropriate therapeutic course.

Non-melanoma Skin Cancer in Canada Chapter 2: Primary Prevention of Non-melanoma Skin Cancer

BACKGROUND

Non-melanoma skin cancer (NMSC), including basal and squamous cell carcinoma (BCC and SCC), represents the most common malignancy.

OBJECTIVE

To provide guidance to Canadian health care practitioners regarding primary prevention of NMSC.

METHODS

Structured literature searches were conducted, using search terms including prevention, sunscreen, and sun prevention factor. All recommendations concern guidance that physicians should regularly discuss with their patients to help establish photoprotection habits. The GRADE system was used to assign strength to each recommendation.

RESULTS

Ultraviolet exposure is the major modifiable risk factor for NMSC. Aspects of photoprotection, including effective sunscreen use and avoidance of both the midday sun and artificial tanning, are discussed. Several widespread misunderstandings that undermine responsible public health measures related to sun safety are addressed.

CONCLUSIONS

Photoprotection represents both an individual priority and a public health imperative. By providing accurate information during routine patient visits, physicians reinforce the need for ongoing skin cancer prevention.