Skin cancer of the head and neck with gross or microscopic perineural involvement: Patterns of failure

Cutaneous Squamous Cell Carcinoma of the Head and Neck: Pathological Features and What They Mean for Prognosis and Treatment

Cutaneous squamous cell carcinoma (cSCC) is one of the most common cancers worldwide, with an incidence that has increased over the past 30 years. Although usually curable with excision, cSCC can become widely metastatic and aggressive with poor outcomes. Whereas the clinical and radiographic extent of any cancer will always guide selection of treatment modality, pathological features of cSCC also play an important role in determining prognosis and, subsequently, the need for further therapy. Therefore, reviewing and summarizing the current literature regarding pathological prognostic indicators of cSCC is essential to improving clinical outcomes. The present literature review yielded depth of invasion, surgical margins, perineural invasion, extranodal extension, lymphovascular invasion, tumor grade, tumor subtype, premalignant lesions, and molecular markers as key prognostic indicators, all with varying recommendations for adjuvant therapy. Notably, some of these factors have not been incorporated into either the American Joint Committee on Cancer staging system (8th edition) or National Comprehensive Cancer Network Clinical Practice Guidelines in Oncology for cSCC. This review highlights a need for further research into these prognostic indicators and their role in determining the need for adjuvant treatment in head and neck cSCC.

Perineural invasion score system and clinical outcomes in resected pancreatic cancer patients

BACKGROUND/OBJECTIVES

Perineural invasion (PNI), classified according to its presence or absence in tumor specimens, is recognized as a poor prognostic factor in pancreatic ductal adenocarcinoma (PDAC) patients. Herein, we identified five histological features of PNI and investigated their impact on survival outcomes of PDAC resected patients.

METHODS

Five histopathological features of PNI (diameter, number, site, sheath involvement, and mitotic figures within perineural invasion) were combined in an additional final score (ranging from 0 to 8), and clinical data of PDAC patients were retrospectively analyzed. PNI + patients were stratified in two categories according to the median score value (<6 and ≥ 6, respectively). Impact of PNI on disease-free survival (DFS) and overall survival (OS) were analyzed.

RESULTS

Forty-five patients were enrolled, of whom 34 with PNI (PNI+) and 11 without PNI (PNI-). The DFS was 11 months vs. not reached (NR) (p = 0.258), while the OS was 19 months vs. NR (p = 0.040) in PNI+ and PNI- patients, respectively. A ≥6 PNI was identified as an independent predictor of worse OS vs. <6 PNI + patients (29 vs. 11 months, p < 0.001) and <6 PNI+ and PNI- patients (43 vs. 11 months, p < 0.001). PNI ≥6 was an independent negative prognostic factor of DFS vs. <6 PNI+ and PNI- patients (13 vs. 6 months, p = 0.022).

CONCLUSIONS

We report a PNI scoring system that stratifies surgically-treated PDAC patients in a graded manner that correlates with patient prognosis better than the current dichotomous (presence/absence) definition. However, further and larger studies are needed to support this PNI scoring system.

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.

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.

Extensive Perineural Invasion vs Nerve Caliber to Assess Cutaneous Squamous Cell Carcinoma Prognosis

Importance

Perineural invasion (PNI) is an adverse risk feature in cutaneous squamous cell carcinoma (CSCC) that affects patient prognosis and disease management. However, research comparing different PNI patterns on patient outcomes is limited.

Objective

To compare 4 assessments of PNI in CSCC, their associations with poor outcomes, and implications for their inclusion in the Brigham and Women's Hospital (BWH) staging system.

Design, Setting, and Participants

This retrospective cohort study was performed at a single tertiary care institution and compared 4 PNI assessments: nerve caliber, number of involved nerves per section, PNI maximal depth, and PNI location with respect to tumor. Patients with primary, localized, invasive CSCC with PNI diagnosed between January 1, 2000, and December 31, 2017, were identified via an electronic in-house database. Available pathology slides were secondarily reviewed by study authors. Relevant patient and tumor characteristics and outcomes were abstracted from the medical record. Data analysis was performed between September 6 and October 20, 2022.

Main Outcomes and Measures

Risks of recurrence, disease-specific death, and a composite end point (any poor outcome) were calculated via multivariable stepwise Fine and Gray competing-risks regression. Considered revisions to the BWH staging system were assessed via receiver operating characteristic curves and test characteristics.

Results

This study included 140 patients with CSCC, with a mean (SD) age of 75.1 (11.2) years. More than half of the patients were men (93 [66.4%]), and most identified as White (132 [94.3%]). Of the 4 PNI assessments studied, only involvement of multiple nerves was associated with poor outcomes. Perineural invasion of 5 or more distinct nerves (extensive PNI [ePNI]) was independently associated with local recurrence (subhazard ratio [SHR], 13.83 [95% CI, 3.50-54.62]; P < .001), disease-specific death (SHR, 6.20 [95% CI, 1.59-24.21]; P = .009), and any poor outcome (SHR, 10.21 [95% CI, 2.88-36.15]; P < .001). A revised BWH staging system with substitution of ePNI for large-caliber PNI resulted in improved area under the curve and test characteristics compared with current BWH staging criteria that use nerve caliber as the measure of PNI.

Conclusions and Relevance

The findings of this cohort study suggest that ePNI is the best prognostic measure of PNI. Because ePNI obviated the need for a micrometer and had superior prognostic capacity to nerve caliber in this cohort, ePNI should be considered for inclusion in CSCC tumor staging. Inclusion of ePNI as a high-risk factor in CSCC staging systems may optimize patient selection for primary treatment and adjuvant interventions.

Risk factors and novel predictive model for metastatic cutaneous squamous cell carcinoma: a population-based analysis

Cutaneous squamous cell carcinoma (cSCC) is one of the most common skin malignancies. Patients with metastatic cSCC (mcSCC) tended to have unfavorable prognosis. However, there is no available models to evaluate the survival outcomes for these patients. This study retrospectively collected mcSCC cases identified from The Surveillance, Epidemiology, and End Results (SEER) database from 2000 to 2018. All patients were randomly divided into the training and validation cohorts. The independent factors which predicted the cancer-specific survival (CSS) were identified by Cox proportional hazard regression analysis, and were used to build nomogram. he discrimination ability of nomograms was evaluated using the concordance index (C-index). The receiver operating characteristic (ROC) curve and the corresponding area under the curve (AUC) at 1, 3, and 5 years were calculated to estimate the predictive accuracy. The performance of this nomogram was evaluated by the calibration curves. The decision curve analyses (DCAs) were conducted to assess the clinical usefulness of the models. Based on the novel nomograms, all patients were classified into low- and high-risk groups. Kaplan-Meier curves were plotted to compare the survival outcomes of two groups. All analyses were conducted by R software (Version 4.1.3). A total of 916 patients were included. Age, marital status, location of the primary sites, number of metastases, T stage, N stage, surgical resection of the primary sites, radiotherapy of the primary sites, and chemotherapy were significantly associated with CSS. A nomogram predicting CSS was built based on these parameters. C-index and ROC curves of nomogram showed promising discriminating and predicting ability for CSS. Survival analysis showed that patients in the low-risk group had significant superior CSS time than those in the high-risk group (median CSS time: 15.0 vs. 5.0 months, p < 0.001). In conclusion, we developed and validated a novel nomogram predicting the CSS in metastatic cSCC patients. This nomogram could be used to assess the prognosis of metastatic cSCC patients, and help clinicians evaluating optimal treatment options for individual patient.

Radiation therapy for low- and high-risk perineural invasion in head and neck cutaneous squamous cell carcinoma: Clinical outcomes and patterns of failure

BACKGROUND

Perineural invasion (PNI) in head and neck squamous cell carcinoma (HNSCC) portends poor prognosis. Extent of treatment of nerve pathways with varying degrees of PNI and patterns of failure following elective neural radiotherapy (RT) remain unclear.

METHODS

Retrospective review of HNSCC patients with high-risk (clinical/gross, large-nerve, extensive) or low-risk (microscopic/focal) PNI who underwent curative-intent treatment from 2010 to 2021.

RESULTS

Forty-four patients (mean follow-up 22 months; 59% high-risk, 41% low-risk PNI) were included. Recurrence following definitive treatment occurred in 31% high-risk and 17% low-risk PNI patients. Among high-risk patients, 69% underwent surgery with post-operative RT and 46% underwent elective neural RT. Local control (83% low-risk vs. 75% high-risk), disease-free, and overall survival did not differ between groups.

CONCLUSIONS

High local control rates were achieved in high-risk PNI patients treated with adjuvant or primary RT, including treatment of both involved and uninvolved, communicating cranial nerves, with few failures in electively treated regions.

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.

Current opinions on diagnosis and treatment of adenoid cystic carcinoma

Adenoid cystic carcinoma (ACC) is a rare malignant tumor derived mainly from the salivary glands, representing approximately 1% of all headandneck carcinomasand 10% of all salivary gland neoplasms. ACC displays a paradoxical behavioral combination of an indolent growth pattern but an aggressive progression, with local recurrence and distant metastasis. The propensity of ACC of the head and neck (ACCHN) for perineural invasion and its anatomical location, especially if it extends to the nasal cavity and paranasal sinuses, facilitates tumor involvement in the surrounding structures, such as the orbit, pterygopalatine fossa, Meckel'scave, and cavernous sinus, which can lead to skull base involvement and intracranial extension. Despite advances in molecular mechanisms and diagnostic imaging, ACC treatment remainschallenging due to the lack ofconsensuson treatment patterns. In this review, we aimed toprovideanupdatedinsight intothe understanding of ACCHN by focusing on clinical behavior, imaging diagnosis, pathological features, and therapeutic strategies. We reviewed the molecular mechanisms, especially in ACCHN with perineural invasion, and elaborated on treatment options, including chemotherapy, targeted therapies, and immunotherapy, to establish a comprehensive understanding of ACC to arrive at a policy for proper diagnosis, preoperative evaluation, and therapeutic strategies.

Management of the parotid for high-risk cutaneous squamous cell carcinoma: A review from the salivary section of the American Head and Neck Society

BACKGROUND

Metastases to the parotid nodal basin in patients with high-risk cutaneous squamous cell carcinoma (HRcSCC) impact disease specific survival (DSS) and overall survival (OS).

METHODS

A writing group convened by the Salivary Section of the American Head and Neck Society (AHNS) developed contemporary, evidence-based recommendations regarding management of the parotid nodal basin in HRcSCC based on available literature, expert consultation, and collective experience. The statements and recommendations were then submitted and approved by the AHNS Salivary Committee.

RESULTS

These recommendations were developed given the wide variation of practitioners who treat HRcSCC in order to streamline management of the parotid nodal basin including indications for imaging, surgery, radiation, and systemic treatment options as well.

CONCLUSIONS

This clinical update represents contemporary optimal management of the parotid nodal basin in HRcSCC and is endorsed by the Salivary Section of the AHNS.

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.

Evidence-Based Consensus Recommendations for the Evolving Treatment of Patients with High-Risk and Advanced Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma is the second most common skin cancer in the United States. Currently, there is no standardized management approach for patients with cutaneous squamous cell carcinoma who develop metastatic or locally advanced disease and are not candidates for curative surgery or curative radiation. To address this issue, the Expert Cutaneous Squamous Cell Carcinoma Leadership program convened an expert steering committee to develop evidence-based consensus recommendations on the basis of a large, structured literature review. Consensus was achieved through modified Delphi methodology. The steering committee included five dermatologists, three medical oncologists, two head and neck surgeons, one radiation oncologist, and a patient advocacy group representative. The steering committee aligned on the following clinical topics: diagnosis and identification of patients considered not candidates for surgery; staging systems and risk stratification in cutaneous squamous cell carcinoma; the role of radiation therapy, surgery, and systemic therapy in the management of advanced disease, with a focus on immunotherapy; referral patterns; survivorship care; and inclusion of the patient's perspective. Consensus was achieved on 34 recommendations addressing 12 key clinical questions. The Expert Cutaneous Squamous Cell Carcinoma Leadership steering committee's evidence-based consensus recommendations may provide healthcare professionals with practically oriented guidance to help optimize outcomes for patients with advanced cutaneous squamous cell carcinoma.

Clinical Perineural Invasion and Immunotherapy for Head and Neck Cutaneous Squamous Cell Carcinoma

OBJECTIVES/HYPOTHESIS

To describe outcomes of advanced head and neck cutaneous squamous cell carcinoma (cSCC) with clinical perineural invasion (cPNI) treated with immune checkpoint inhibitor (ICI) therapy, and to describe post-treatment radiographic findings in the context of clinical response to treatment using a new grading system.

STUDY DESIGN

Retrospective chart review.

METHODS

Retrospective chart review was performed for 11 patients treated with ICI for head and neck cSCC with cPNI of large named nerves. The primary outcome was response to treatment as defined by radiographic and clinical evidence. Clinical responses were defined as improvement in symptoms of neuropathic pain, hypoesthesia, nerve weakness, or decrease in visible tumor. Imaging studies were graded based on a new classification system for perineural invasion and reviewed by two neuroradiologists since RECISTv1.1 is inadequate to adjudicate response in these patients.

RESULTS

Nine (82%) patients had radiographic perineural disease control on ICI. Eight patients had improved radiographic perineural disease and one had stable disease. Of these, complete resolution of radiographic evidence of perineural disease was seen in only one patient. Seven (64%) patients had clinical responses, with either improved or stable radiographic disease.

CONCLUSIONS

ICI therapy is a viable treatment option for head and neck cSCC with cPNI. Radiographic and clinical evidence of response correlate well, with improvement in neuropathic pain being the most sensitive clinical marker of response. Even with favorable findings on repeat imaging and stable clinical course, complete resolution of perineural thickening and enhancement is rare. A grading system for classifying changes in perineural disease over time is proposed.

LEVEL OF EVIDENCE

4 Laryngoscope, 2021.

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.

Adjuvant therapy for high-risk cutaneous squamous cell carcinoma: 10-year review

Standard of care for high-risk cutaneous squamous cell carcinoma (cSCC) is surgical excision of the primary lesion with clear margins when possible, and additional resection of positive margins when feasible. Even with negative margins, certain high-risk factors warrant consideration of adjuvant therapy. However, which patients might benefit from adjuvant therapy is unclear, and supporting evidence is conflicting and limited to mostly small retrospective cohorts. Here, we review literature from the last decade regarding adjuvant radiation therapy and systemic therapy in high-risk cSCC, including recent and current trials and the role of immune checkpoint inhibitors. We demonstrate evidence gaps in adjuvant therapy for high-risk cSCC and the need for prognostic tools, such as gene expression profiling, to guide patient selection. More large-cohort clinical studies are needed for collecting high-quality, evidence-based data for determining which patients with high-risk cSCC may benefit from adjuvant therapy and which therapy is most appropriate for patient management.

A Histopathologic Scoring System for Perineural Invasion Correlates With Adverse Outcomes in Patients With Cutaneous Squamous Cell Carcinoma

BACKGROUND

Perineural invasion (PNI) is a known risk factor for recurrence, metastasis, and death in cutaneous squamous cell carcinoma (cSCC). Current staging systems include PNI, but none define its extent or severity.

OBJECTIVE

To identify histopathologic features of cSCC with PNI that may be associated with adverse outcomes.

MATERIALS AND METHODS

This is a retrospective cohort study that included 45 patients with cSCC and PNI treated with surgical excision. Histopathologic slides were analyzed for 5 features of PNI: largest affected nerve diameter, number of nerves affected, depth of nerve involvement, intra- versus extratumoral PNI, and focal versus circumferential PNI.

RESULTS

The median largest affected nerve diameter was 0.13 mm, and the median number of nerve structures involved was 4. After a median follow-up time of 24 months, 6 patients developed adverse outcomes, including 2 local recurrences, 4 metastases, and 2 tumor-related deaths. Univariate logistic regression analysis revealed that nerve diameter and number of affected nerves were significantly associated with adverse outcome. A composite PNI score, calculated from 5 histopathologic features, was the strongest predictor of adverse outcome (p = .020).

CONCLUSION

Histopathologic features of PNI can be quantified with a composite PNI score that is significantly associated with adverse outcomes in cSCC.

Cutaneous Malignancies of the Head and Neck

Cutaneous malignancies (CMs), or skin cancers, are the most common cancer worldwide, with a quarter million cases diagnosed annually in the United States alone. The best described risk factor for CM is ultraviolet radiation from sunlight, and therefore most of these cancers develop in sun-exposed skin, including the head and neck. Beginning with melanoma, immunotherapy has increasingly been used over the past decade for treatment of unresectable CM, and immune checkpoint inhibitors are now Food and Drug Administration-approved for first-line treatment of unresectable melanoma, Merkel cell carcinoma, and cutaneous squamous cell carcinoma, and second-line for basal cell carcinoma.

Passively Scattered Proton Therapy for Nonmelanoma Skin Cancer with Clinical Perineural Invasion

Purpose

To report our experience with the delivery of passively scattered proton therapy in the management of nonmelanoma skin cancers with clinical perineural invasion.

Materials and Methods

We reviewed the medical records of patients who received definitive or postoperative proton therapy for nonmelanoma skin cancer with clinical perineural invasion at our institution and updated patient follow-up when possible. All patients were treated with curative intent with or without the delivery of concurrent systemic therapy. We report disease control rates and the rates of late toxicity among this cohort.

Results

Twenty-six patients treated between 2008 and 2017 were included in the analysis. Following proton therapy, the 3-year overall, cause-specific, and disease-free survival rates were 59%, 73%, and 60%, respectively. The 3-year local control, local regional control, and distant metastasis-free survival rates were 80%, 65%, and 96%, respectively. On univariate analysis, surgical resection before radiation therapy significantly improved local regional control rates at 3 years (55% versus 86%; P = .04). Grade 3+ late toxicities occurred in 13 patients (50%) and the most common toxicities included grade 3+ keratitis of the ipsilateral eye, which occurred in 4 patients (15%) and grade 3+ brain necrosis in 4 patients (15%).

Conclusion

Proton therapy is effective in the management of nonmelanoma skin cancer with clinical perineural invasion. Although disease control and complication rates compare favorably to those previously published for photon-based radiation therapy, the risk for late toxicity is significant and patients should be appropriately counseled.

The role of radiation therapy in the management of cutaneous malignancies. Part II: When is radiation therapy indicated?

Radiation therapy may be performed for a variety of cutaneous malignancies, depending on patient health status, tumor clinical and histologic features, patient preference, and resource availability. Dermatologists should be able to recognize the clinical scenarios in which radiation therapy is appropriate, as this may reduce morbidity, decrease risk of disease recurrence, and improve quality of life. The second article in this 2-part continuing medical education series focuses on the most common indications for radiation therapy in the treatment of basal cell carcinoma, cutaneous squamous cell carcinoma, dermatofibrosarcoma protuberans, Merkel cell carcinoma, Kaposi sarcoma, angiosarcoma, cutaneous lymphoma, melanoma, undifferentiated pleomorphic sarcoma, and sebaceous carcinoma.

The role of radiation therapy in the management of cutaneous malignancies. Part I: Diagnostic modalities and applications

Radiation therapy offers distinct advantages over other currently available treatments for cutaneous malignancies in certain circumstances. Dermatologists and dermatologic surgeons should be familiar with the available radiation therapy techniques as well as their value and potential limitations in a variety of clinical scenarios. The first article in this 2-part continuing medical education series highlights the mechanisms, modalities, and applications of the most commonly used radiotherapy treatments as they relate to cutaneous oncology. We review the current indications for the use of radiation in the treatment of various cutaneous malignancies, the techniques commonly employed in modern radiotherapy, and the associated complications.

Radiation Therapy for Cutaneous Malignancies of the Head and Neck

Radiation therapy plays an integral role in the management of cutaneous malignancies of the head and neck. This article highlights the use of radiation therapy in the definitive and adjuvant setting for basal cell carcinoma, cutaneous squamous cell carcinoma, melanoma, and Merkel cell carcinoma. Themes that emerge include the overall efficacy of radiation therapy as a local therapy, the relevance of cosmesis, functional outcomes, late toxicities as secondary end points, and the multitude of treatment modalities that are used.

Cutaneous Head and Neck Cancers in the High-Risk Immunosuppressed Population

The immunosuppressed (IS) population encompasses a diverse cohort of patients to include iatrogenically immunocompromised organ transplant recipients as well as patients with chronic lymphoid malignancies, human immunodeficiency virus/acquired immunodeficiency syndrome, and autoimmune disorders. Cutaneous cancers in this high-risk patient group are clinically distinct from the general immunocompetent population, showing aggressive behavior with associated poor outcomes. This article reviews the pathogenesis, epidemiology, incidence, prognosis, and special considerations required in managing cutaneous cancers in the IS patient population.

Perineural Invasion As the Sole Pathologic Risk Factor After Surgical Resection for Head and Neck Squamous Cell Carcinoma

Introduction Postoperative radiotherapy (PORT) is routinely recommended for patients with head and neck squamous cell carcinoma (HNSCC) based on pathologic risk factors (pRFs) such as perineural invasion (PNI). Patients with PNI as the sole pRF after resection of HNSCC are uncommon and their prognosis is less clear. The aim of this study is to assess the role of PNI as a sole risk factor in patients with otherwise pathologically low-risk HNSCC. Methods Patients with HNSCC of the oral cavity, pharynx, or larynx treated with primary surgical resection from 2013 to 2018 were identified from an institutional cancer registry. Those with pRFs (pathologic T3-4 disease, lymphovascular space invasion [LVSI], multiple positive lymph nodes, close [within 2 mm] or positive margins, extranodal extension [ENE], or recurrent disease) were excluded, yielding an otherwise pathologically low-risk cohort with or without incidental, pathologic PNI. Locoregional control (LRC), overall survival (OS) and disease-specific survival (DSS) were estimated and compared between PNI groups and by adjuvant therapy. Results A total of 1,058 patients were identified as having undergone surgical resection. Exclusion of patients with other pRFs, those with unknown PNI, and oral cavity patients with depth of invasion > 10 mm yielded a study cohort of 85 patients. Eight patients (10% of study group, <1% of all patients) had PNI as the sole pRF, none of which had clinical signs or symptoms of perineural tumor spread. The remaining 77 were negative for PNI and thus pathologically low risk. Patients with PNI were more likely to have oral cavity cancer, to be younger, and to have received PORT than those without PNI; no patient received concurrent chemotherapy. At a median follow-up of 46.4 months, two- and five-year LRC rates were 81.4% and 78.5%, respectively. No differences were noted between PNI-positive and PNI-negative groups (p=0.73) or PORT v. no-PORT groups (p=0.39). While the utility of PORT is not possible to assess given limited sample size, four patients with PNI who did not receive PORT did not experience locoregional failure. Seventeen patients overall experienced locoregional failure and 14 were ultimately salvaged. Five-year OS and DSS were 77.4% and 90.8%, respectively. Conclusion Patients with pathologically low-risk HNSCC after surgical resection experience high rates of LRC. In this large institutional cohort, PNI as the sole pRF was exceedingly rare, and the benefit of adjuvant therapies is difficult to assess. Within this limitation, PORT remains the standard of care for patients with PNI to reduce the risk of locoregional failure. Further collaborative studies are required to adequately assess the prognostic impact of PNI alone in resected HNSCC.

Artificial neural networks allow response prediction in squamous cell carcinoma of the scalp treated with radiotherapy

BACKGROUND

Epithelial neoplasms of the scalp account for approximately 2% of all skin cancers and for about 10-20% of the tumours affecting the head and neck area. Radiotherapy is suggested for localized cutaneous squamous cell carcinomas (cSCC) without lymph node involvement, multiple or extensive lesions, for patients refusing surgery, for patients with a poor general medical status, as adjuvant for incompletely excised lesions and/or as a palliative treatment. To date, prognostic risk factors in scalp cSCC patients are poorly characterized.

OBJECTIVE

To identify patterns of patients with higher risk of postradiotherapy recurrence.

METHODS

A retrospective observational study was performed on scalp cSCC patients with histological diagnosis who underwent conventional radiotherapy (50-120 kV) (between 1996 and 2008, follow-up from 1 to 140 months, median 14 months). Out of the 79 enrolled patients, 22 (27.8%) had previously undergone a surgery. Two months after radiotherapy, 66 (83.5%) patients achieved a complete remission, 6 (7.6%) a partial remission, whereas 2 (2.5%) proved non-responsive to the treatment and 5 cases were lost to follow-up. Demographical and clinical data were preliminarily analysed with classical descriptive statistics and with principal component analysis. All data were then re-evaluated with a machine learning-based approach using a 4th generation artificial neural networks (ANNs)-based algorithm.

RESULTS

Artificial neural networks analysis revealed four scalp cSCC profiles among radiotherapy responsive patients, not previously described: namely, (i) stage T2 cSCC type, aged 70-80 years; (ii) frontal cSCC type, aged <70 years; (iii) non-recurrent nodular or nodulo-ulcerated, stage T3 cSCC type, of the vertex and treated with >60 Grays (Gy); and (iv) flat, occipital, stage T1 cSCC type, treated with 50-59 Gy. The model uncovering these four predictive profiles displayed 85.7% sensitivity, 97.6% specificity and 91.7% overall accuracy.

CONCLUSIONS

Patient profiling/phenotyping with machine learning may be a new, helpful method to stratify patients with scalp cSCCs who may benefit from a RT-treatment.

Evaluation of the utility of localized adjuvant radiation for node-negative primary cutaneous squamous cell carcinoma with clear histologic margins

BACKGROUND

Though the National Comprehensive Cancer Network recommends consideration of localized adjuvant radiation after clear-margin surgery for cutaneous squamous cell carcinoma (cSCC) with large-caliber (≥0.1-mm) nerve invasion (LCNI) and other high-risk features, only a single small study has compared surgery plus adjuvant radiation therapy (S+ART) to surgical monotherapy (SM) for cSCC.

OBJECTIVE

Compare S+ART to SM for primary cSCCs with LCNI and other risk factors.

METHODS

Matched retrospective cohort study of primary cSCCs (matched on sex, age, immune status, type of surgery, diameter, differentiation, depth, and LCNI) treated with S+ART versus SM. A subgroup analysis of cSCCs with LCNI was performed.

RESULTS

In total, 62 cSCCs were included in matched analysis (31 S+ART and 31 SM) and 33 cSCCs in the LCNI analysis (16 S+ART and 17 SM). There were no significant differences in local recurrence, metastasis, or death from disease in either analysis. Risk of local recurrence was low (8%, 7/89), with 3 of the local recurrences being effectively treated upon recurrence.

LIMITATIONS

Single academic center and nonrandomized design.

CONCLUSION

Adjuvant radiation did not improve outcomes compared with SM due to a low baseline risk of recurrence, although adjuvant radiation for named nerve invasion and LCNI of ≥3 nerves has been shown to improve outcomes in a prior study. Randomized studies are needed to define the subset of cSCC for whom adjuvant radiation has utility.

Definitive and Postoperative Radiation Therapy for Basal and Squamous Cell Cancers of the Skin: Executive Summary of an American Society for Radiation Oncology Clinical Practice Guideline

PURPOSE

This guideline reviews the evidence for the use of definitive and postoperative radiation therapy (RT) in patients with basal cell carcinoma (BCC) and cutaneous squamous cell carcinoma (cSCC).

METHODS

The American Society for Radiation Oncology convened a task force to address 5 key questions focused on indications for RT in the definitive and postoperative setting for BCC and cSCC, as well as dose-fractionation schemes, target volumes, basic aspects of treatment planning, choice of radiation modality, and the role of systemic therapy in combination with radiation. Recommendations were based on a systematic literature review and created using a predefined consensus-building methodology and system for grading evidence quality and recommendation strength.

RESULTS

The guideline recommends definitive RT as primary treatment for patients with BCC and cSCC who are not surgical candidates while conditionally recommending RT with an emphasis on shared decision-making in those situations in which adequate resection can lead to a less than satisfactory cosmetic or functional outcome. In the postoperative setting, a number of indications for RT after an adequate resection are provided while distinguishing the strength of the recommendations between BCC and cSCC. One key question is dedicated to defining indications for regional nodal irradiation. The task force suggests a range of appropriate dose-fractionation schemes for treatment of primary and nodal volumes in definitive and postoperative scenarios. The guideline also recommends against the use of carboplatin concurrently with adjuvant RT and conditionally recommends the use of systemic therapies for unresectable primaries where treatment may need escalation.

CONCLUSIONS

Defining the role of RT in the management of BCC and cSCC has been hindered by a lack of high-quality evidence. This document synthesizes available evidence to define practice guidelines for the most common clinical situations. We encourage practitioners to enroll patients in prospective trials and to approach care in a multidisciplinary fashion whenever possible.

Outcomes following radiation for cutaneous squamous cell carcinoma of the head and neck: Associations between immune suppression and recurrence

BACKGROUND

Data evaluating outcomes and patterns of recurrence following radiation therapy (RT) for cutaneous squamous cell carcinoma (cSCC) of the head and neck are limited.

METHODS

We performed a retrospective analysis of 111 head and neck cSCC patients treated with RT at 4 affiliated institutions.

RESULTS

With median follow-up of 7 months, there were 29 (26%) recurrences, 73% of which were nodal (n = 21). Immunosuppression (IS) was the only factor associated with recurrence (47% in IS, 22% in non-IS, P = .04), and also with time to recurrence in multivariate analysis (HR 5.5; P = .03). No factors were associated with recurrence among patients who received definitive RT. The majority of patients who recurred were salvaged with surgery (n = 20, 69%).

CONCLUSION

In a cohort of cSCC treated with radiotherapy, there was an association between IS and increased failure risk. The majority of failures were salvaged surgically.

The Value of Adjuvant Radiotherapy in Cutaneous Squamous Cell Carcinoma: A Review

Cutaneous squamous cell carcinoma (cSCC) is the second most common cancer in humans and its incidence is rising. Although surgery is the treatment of choice for cSCC, postoperative adjuvant radiotherapy has an important role in local and locorregional disease control. In this review, we analyze the value of postoperative radiotherapy in the management of high-risk cSCC (in particular, cases with perineural invasion), cSCC with positive surgical margins, and locally advanced cSCC (with parotid gland and/or lymph node metastasis).

A new evidence-based risk stratification system for cutaneous squamous cell carcinoma into low, intermediate, and high risk groups with implications for management

Most primary cutaneous squamous cell carcinomas are cured with surgery. A subset, however, may develop local and nodal metastasis that may eventuate in disease-specific; death. This subset has been variably termed high risk. Herein, we review; an emerging body of data on the risks of these outcomes and propose an evidence-based; risk stratification for low-, intermediate-, and high-risk tumors that takes into; account both tumor and patient characteristics. Finally, we discuss a framework for; management of these tumors on the basis of data, when available, and our; recommendations when data are sparse.

Clinical and Incidental Perineural Invasion of Cutaneous Squamous Cell Carcinoma: A Systematic Review and Pooled Analysis of Outcomes Data

Importance

Perineural invasion (PNI) in cutaneous squamous cell carcinoma (CSCC) has been associated with an increased risk of poor outcomes. Patients with PNI may present with clinical symptoms and/or radiologic evidence of PNI (clinical PNI [CPNI]), yet most patients are asymptomatic and PNI is often found on histologic examination (incidental PNI [IPNI]). Evidence-based estimates of the risks of disease-related outcomes comparing IPNI and CPNI are limited in the dermatology literature.

Objectives

To review and synthesize outcomes data for patients with CSCC and CPNI or IPNI.

Data Sources

A systematic review was conducted in MEDLINE and EMBASE for English-language articles published since inception to November 11, 2016.

Study Selection

All studies that reported a disease-related outcome (local recurrence, nodal metastasis, distant metastasis, or disease-specific death) of CSCCs with CPNI and IPNI were included.

Data Extraction and Synthesis

Articles were screened for eligibility, and any possible discrepancies in this screening were resolved. Data extracted included study characteristics, tumor characteristics, treatments performed, and disease-related outcomes. Overall risks of disease-related outcomes were generated by pooling patients from eligible studies. χ2 Statistics and Fisher exact tests were used to evaluate differences in disease-related outcomes.

Main Outcomes and Measures

Risks of disease-related outcomes and 5-year recurrence-free, disease-specific, and overall survival.

Results

A total of 12 studies containing 241 patients with CPNI and 381 patients with IPNI were included in the systematic review and analysis. The overall risks of local recurrence and disease-specific death were significantly higher in patients with CSCC and CPNI compared with those with CSCC and IPNI (local recurrence, 37% vs 17%; P < .001; disease-specific death, 27% vs 6%; P < .001). The risks of nodal metastasis and distant metastasis did not differ significantly by PNI classification. Patients with CSCC and CPNI had poorer mean 5-year recurrence-free survival and disease-specific survival compared with patients with IPNI (recurrence-free survival, 61% vs 76%; P = .009; disease-specific survival, 70% vs 88%; P = .002).

Conclusions and Relevance

Patients with CSCC and CPNI are at an increased risk of local recurrence and disease-specific death compared with patients with CSCC and IPNI and have a 30% risk of death. Patients with PNI may benefit from increased long-term surveillance. Further studies are needed to establish standardized guidelines on follow-up and dermatologic surveillance in this high-risk patient population.