Imiquimod 5% cream monotherapy for cutaneous squamous cell carcinoma in situ (Bowen's disease): A randomized, double-blind, placebo-controlled trial

Efficacy of interventions for cutaneous squamous cell carcinoma in situ (Bowen's disease): A systematic review and meta-analysis of proportions

BACKGROUND

Cutaneous squamous cell carcinoma in situ (Bowen's disease) is a precancerous condition confined to the epidermis of the skin. Despite the critical need for effective interventions to halt its progression, there remains a notable shortage of comprehensive data comparing the efficacy of various therapeutic approaches.

OBJECTIVES

This systematic review and meta-analysis endeavour to compare the different efficacies of interventions by investigating and synthesizing data from numerous trials.

METHODS

A pre-defined protocol was registered in PROSPERO (CRD42021242224, registration date: 16 April 2021). Systematic searches in Medline, Embase and Central, along with manual trial register searches, identified studies reporting lesion clearance rates (LCR), participant clearance rates (PCR) or recurrence rates (date of last search: 12 June 2024). Quality assessment followed guidelines from the National Heart, Lung, and Blood Institute (NHLBI). After the study arms were categorized into treatment groups and groups of study quality, the proportions were pooled using the generalized linear mixed model (GLMM) as meta-analytical method.

RESULTS

A comprehensive inclusion of 71 studies facilitated an evaluation of 3783 lesions for LCR, 1225 patients for PCR, 4073 lesions for lesion recurrence rates (LRR) and 740 patients for participant recurrence rates (PRR). Surgery demonstrated the highest LCR and PCR (0.97, 95% confidence interval (CI): 0.90-0.99) and the lowest LRR (0.04, 95% CI: 0.02-0.07).

CONCLUSIONS

This study provides a thorough overview of reported efficacy outcomes for practice-relevant interventions for Bowen's disease. Surgery outperformed other treatments for Bowen's disease. For the other intervention groups, it was not possible to show clear differences in effectiveness: LCR, PCR, LRR and PRR showed various treatment rankings, and the comparability was restricted by different numbers of studies between treatment groups and outcome measures, methodical and clinical heterogeneity. Further high-quality studies are needed to investigate practice-relevant interventions for Bowen's disease.

Therapeutic Approaches for Non-Melanoma Skin Cancer: Standard of Care and Emerging Modalities

Skin cancer encompasses a range of cutaneous malignancies, with non-melanoma skin cancers (NMSCs) being the most common neoplasm worldwide. Skin exposure is the leading risk factor for initiating NMSC. Ultraviolet (UV) light induces various genomic aberrations in both tumor-promoting and tumor-suppressing genes in epidermal cells. In conjunction with interactions with a changed stromal microenvironment and local immune suppression, these aberrations contribute to the occurrence and expansion of cancerous lesions. Surgical excision is still the most common treatment for these lesions; however, locally advanced or metastatic disease significantly increases the chances of morbidity or death. In recent years, numerous pharmacological targets were found through extensive research on the pathogenic mechanisms of NMSCs, leading to the development of novel treatments including Hedgehog pathway inhibitors for advanced and metastatic basal cell carcinoma (BCC) and PD-1/PD-L1 inhibitors for locally advanced cutaneous squamous cell carcinoma (cSCC) and Merkel cell carcinoma (MCC). Despite the efficacy of these new drugs, drug resistance and tolerability issues often arise with long-term treatment. Ongoing studies aim to identify alternative strategies with reduced adverse effects and increased tolerability. This review summarizes the current and emerging therapies used to treat NMSC.

Topical Treatment of Cutaneous Squamous Cell Carcinoma in Situ and the Impact of Clinical Risk Factors and Positive Histologic Margins at the Time of Diagnosis

BACKGROUND

Limited data exist for the efficacy of topical 5-fluorouracil (5-FU) and imiquimod for cutaneous squamous cell carcinoma (cSCC) in situ (cSCCis) with positive histologic margins at the time of diagnosis.

OBJECTIVE

Identify the efficacy of topical 5-FU and imiquimod in the treatment of cSCCis with positive histologic margins at the time of diagnosis in relation to clinical risk factors.

MATERIALS AND METHODS

Pathology records were screened at a single institution from 2014 to 2021 for cSCCis with positive histologic margins. Patients were included if they were treated with curative intent with topical 5-FU or imiquimod. Recurrences were evaluated in relation to multiple clinical risk factors.

RESULTS

Of 215 patients treated with 5-FU or imiquimod after biopsy-proven cSCCis, 19 patients had recurrent cSCCis and 1 patient had upstaging to invasive cSCC. Recurrence was more likely in larger lesions at the time of initial biopsy ( p = .033) and in patients treated with topical imiquimod compared with topical 5-FU ( p < .01).

CONCLUSION

Topical 5-FU is an appropriate therapy for cSCCis in the correct clinical scenario. Extra consideration should be taken for use of 5-FU in larger diameter cSCCis lesions. Although limited by sample size, our study does not support the use of imiquimod for cSCCis.

Squamous cell carcinoma of the eyelid

Eyelid squamous cell carcinoma is a major type of rare eyelid cancer, together with basal cell carcinoma and sebaceous gland carcinoma. It is a painless disease that progresses slowly and is often detected by the appearance of nodules or plaques. Risk factors include exposure to ultraviolet light, fair skin, radiation and human papillomavirus infection. The standard treatment is surgical removal, and in cases of orbital invasion, orbital content removal is required. If sentinel node biopsy reveals a high risk of lymph node metastasis, adjuvant radiotherapy may be considered. Local chemotherapy, such as imiquimod and 5-fluorouracil, may be used for eyelid squamous cell carcinoma in situ. When surgery or radiotherapy is not recommended for distant metastases or locally advanced disease, drug therapy is often according to head and neck squamous cell carcinoma in Japan. The treatment often requires a multidisciplinary team to ensure the preservation of function and cosmetic appearance.

Harnessing Nanomaterials for Cancer Sonodynamic Immunotherapy

Immunotherapy has made remarkable strides in cancer therapy over the past decade. However, such emerging therapy still suffers from the low response rates and immune-related adverse events. Various strategies have been developed to overcome these serious challenges. Therein, sonodynamic therapy (SDT), as a non-invasive treatment, has received ever-increasing attention especially in the treatment of deep-seated tumors. Significantly, SDT can effectively induce immunogenic cell death to trigger systemic anti-tumor immune response, termed sonodynamic immunotherapy. The rapid development of nanotechnology has revolutionized SDT effects with robust immune response induction. As a result, more and more innovative nanosonosensitizers and synergistic treatment modalities are established with superior efficacy and safe profile. In this review, the recent advances in cancer sonodynamic immunotherapy are summarized with a particular emphasis on how nanotechnology can be explored to harness SDT for amplifying anti-tumor immune response. Moreover, the current challenges in this field and the prospects for its clinical translation are also presented. It is anticipated that this review can provide rational guidance and facilitate the development of nanomaterials-assisted sonodynamic immunotherapy, helping to pave the way for next-generation cancer therapy and eventually achieve a durable response in patients.

Advances in cutaneous squamous cell carcinoma

Human malignancies arise predominantly in tissues of epithelial origin, where the stepwise transformation from healthy epithelium to premalignant dysplasia to invasive neoplasia involves sequential dysregulation of biological networks that govern essential functions of epithelial homeostasis. Cutaneous squamous cell carcinoma (cSCC) is a prototype epithelial malignancy, often with a high tumour mutational burden. A plethora of risk genes, dominated by UV-induced sun damage, drive disease progression in conjunction with stromal interactions and local immunomodulation, enabling continuous tumour growth. Recent studies have identified subpopulations of SCC cells that specifically interact with the tumour microenvironment. These advances, along with increased knowledge of the impact of germline genetics and somatic mutations on cSCC development, have led to a greater appreciation of the complexity of skin cancer pathogenesis and have enabled progress in neoadjuvant immunotherapy, which has improved pathological complete response rates. Although measures for the prevention and therapeutic management of cSCC are associated with clinical benefit, the prognosis remains poor for advanced disease. Elucidating how the genetic mechanisms that drive cSCC interact with the tumour microenvironment is a current focus in efforts to understand, prevent and treat cSCC.

Immunotherapy for keratinocyte cancers. Part I: Immune-related epidemiology, risk factors, pathogenesis, and immunotherapy management of keratinocyte cancers

The important role of the immune system in the surveillance and control of keratinocyte cancers (KCs), namely squamous and basal cell carcinomas, is increasingly appreciated, as new immunotherapies have recently become available. As the field of immunotherapy is rapidly evolving, this review synthesizes key concepts and highlights important cellular components within the immune system responsible for attacking KCs. We review the most current data on the epidemiology, risk factors, and immunotherapy management for KCs. Patients will seek advice from dermatologists to help explain why immunotherapies work for KCs and whether they might be appropriate for different clinical scenarios. Collaboration with medical colleagues across different disciplines to evaluate KCs for response to immunotherapy and early recognition of immune-related adverse events will help to optimize patient outcomes.

Immunomodulators for Non-Melanoma Skin Cancers: Updated Perspectives

Non-melanoma skin cancers (NMSCs) are the most common cancers worldwide and may be associated with significant morbidity and mortality, especially in immunosuppressed populations. Successful management of NMSC must take primary, secondary and tertiary prevention strategies into consideration. In response to an improved understanding of the pathophysiology of NMSC and associated risk factors, multiple systemic and topical immunomodulatory drugs have been developed and integrated into clinical practice. Many of these drugs are efficacious in the prevention and treatment of precursor lesions (actinic keratoses; AKs), low-risk NMSC, and advanced disease. The identification of patients at high risk for the development of NMSC is critical in reducing disease morbidity. Understanding the various treatment options available and their comparative effectiveness is paramount for developing a personalized treatment regimen for such patients. This review article provides an updated overview of the various topical and systemic immunomodulatory drugs available for the prevention and treatment of NMSC, and the published data supporting their use in clinical practice.

Advances in Topical Treatments of Cutaneous Malignancies

Surgical excision has been the preferred treatment for cutaneous malignancies, but can be affected by various considerations. Noninvasive, self-administered topical treatments represent an alternative option. The aim of this review was to evaluate and summarize evidence-based recommendations for topical treatments of basal cell carcinoma (BCC), cutaneous squamous cell carcinoma (CSCC), in situ melanoma (MIS), and extramammary Paget's disease (EMPD). Studies were reviewed on PubMed. Included studies were summarized, assessed for biases, and assigned a level of evidence to develop treatment recommendations. For the treatment of superficial BCC, complete clearance rates ranged from 90 to 93% for 5% 5-fluorouracil (5-FU) and 71 to 76% for imiquimod (IMQ). For the treatment of nodular BCC, clearance rates for photodynamic therapy (PDT) were 91% at 3 months, with a sustained lesion clearance response rate of 76% after 5 years of follow-up. Clearance rates were 53 to 76% with IMQ. For squamous cell carcinoma in situ, clearance rates ranged from 52 to 98% for PDT, 67 to 92% for 5-FU, and 75 to 93% for IMQ. For MIS, clearance rates ranged from 53 to 92% for IMQ. For EMPD, 54% of 110 patients in cohort studies and case series had a clinical complete response with IMQ. While surgical intervention remains the standard of care for skin cancer, non-invasive, self-administered topical treatments are highly desirable alternative options. Ultimately, the patient and provider should find a treatment modality that aligns with the patient's expectations and maintenance of quality of life.

Squamous Cell Carcinoma in Situ of the Nail Unit: Current Evidence and Recommendations for Patient Centered Treatment

Squamous cell carcinoma in situ of the hand and nail is an infrequent tumor but represents the majority of hand and nail malignancies. While the conventional treatments of invasive nail unit squamous cell carcinoma include Mohs micrographic surgery, wide local excision, or distal digit amputation, no standardized management paradigm for in situ disease exists and the necessity of surgical options is debated. This review aims to discuss the most commonly reported treatment methods and critically assess relevant management considerations in order to facilitate appropriate treatment decisions for nail unit SCCis across dermatologic practice settings. Assessment of the current literature reveals insufficient evidence to determine a standardized treatment for nail unit squamous cell carcinoma in situ. Rather, management is greatly impacted by multiple factors including the presence of subungual involvement, surgical candidacy, importance of curative treatment, and patient preferences regarding cosmesis and function versus cure. When cure is desired, Mohs micrographic surgery is the treatment of choice in most cases. In the setting of desired curative intent, but poor surgical candidacy, radiotherapy may be effective and provide a reasonable chance of functional and cosmetic preservation. Other methods including photodynamic therapy, electrodesiccation and curettage, cryotherapy, and intralesional chemotherapeutics may be appropriate in specific circumstances, but are generally limited by lack of evidence or impracticalities. Lastly, observation with palliation may be appropriate when considering exceedingly rare disease-related mortality.

Toll-like receptor-targeted anti-tumor therapies: Advances and challenges

Toll-like receptors (TLRs) are pattern recognition receptors, originally discovered to stimulate innate immune reactions against microbial infection. TLRs also play essential roles in bridging the innate and adaptive immune system, playing multiple roles in inflammation, autoimmune diseases, and cancer. Thanks to the immune stimulatory potential of TLRs, TLR-targeted strategies in cancer treatment have proved to be able to regulate the tumor microenvironment towards tumoricidal phenotypes. Quantities of pre-clinical studies and clinical trials using TLR-targeted strategies in treating cancer have been initiated, with some drugs already becoming part of standard care. Here we review the structure, ligand, signaling pathways, and expression of TLRs; we then provide an overview of the pre-clinical studies and an updated clinical trial watch targeting each TLR in cancer treatment; and finally, we discuss the challenges and prospects of TLR-targeted therapy.

Analysis on the Effectiveness and Characteristics of Treatment Modalities for Bowen’s Disease: An Observational Study

Treatment options for Bowen’s disease (BD) include surgical excision, cryotherapy, curettage with cautery, topical 5-fluorouracil or imiquimod, and photodynamic therapy. However, it is not clear which treatment is the most effective due to lack of studies. We reviewed the electronic medical records of 158 patients who were diagnosed with BD and treated at Seoul St. Mary’s Hospital from January 2011 to December 2020. Treatment modalities were surgical excision, cryotherapy, photodynamic therapy, and imiquimod. A total of 121 patients was enrolled in this study. The average treatment period was longest for cryotherapy, followed by imiquimod, PDT, and excision (119.53, 87.75, 68.50, and 1 day, respectively). The therapeutic efficacy was highest in the surgical excision group (100%) and lowest in the PDT group (62.5%). The recurrence rate was highest in the imiquimod group (33.33%). Surprisingly, only in patients treated with cryotherapy, satellite lesions developed in 9.09% of them during follow-up. Surgical excision exhibited the highest clearance rate and the lowest recurrence rate, and its treatment period was the shortest, confirming that it remains the gold standard. In contrast, since cryotherapy demonstrated a relatively high recurrence rate including development of satellite lesions, careful monitoring is required when performing cryotherapy for treatment of BD.

Durable Clearance Rate of Photodynamic Therapy for Bowen Disease and Cutaneous Squamous Cell Carcinoma: A Systematic Review and Meta-Analysis

BACKGROUND

Although surgery is the treatment of choice for Bowen disease (BD) and cutaneous squamous cell carcinoma (cSCC), nonsurgical treatments such as photodynamic therapy (PDT) may be preferred for select tumors. Previous meta-analysis have failed to gather strong evidence to recommend PDT.

OBJECTIVE

This study evaluates the effectiveness of PDT in the treatment of cSCC and BD for clearance rate (CR) after 1 year.

METHODS

A literature search of studies of biopsy-proven BD and cSCC treated with PDT was performed. Pooled CRs were estimated. Subgroup analyses were performed based on follow-up, treatment regimen, lesion size, and site.

RESULTS

Forty-three studies were included, enrolling 1943 BD lesions and 282 SCC lesions. Pooled CRs for BD and SCC were 76% (95% CI: 71%-80%; I2 = 78.9%) and 51% (95% CI: 35%-66%; I2 = 85.7%), respectively.

CONCLUSION

Our findings support the selective use of PDT for BD; however, patients should be advised of potential for recurrence. Although PDT can be used for certain cases of cSCC, the high rate of treatment failure necessitates close surveillance for residual or recurrent disease. Further studies are needed to justify the usage of PDT in the treatment of BD and cSCC.

Efficacy of Non-excisional Treatment Modalities for Superficially Invasive and In Situ Squamous Cell Carcinoma: A Systematic Review and Meta-analysis

BACKGROUND

Squamous cell carcinoma in situ (SCCIS) and squamous cell carcinoma (SCC) are prevalent conditions that are increasing in incidence worldwide. Many non-excisional treatments are commonly used, but the efficacy of these treatments is not well delineated.

OBJECTIVE

To examine the recurrence rates of SCCIS and SCC treated with non-excisional treatment modalities.

METHODS

A systematic review and meta-analysis was performed for SCCIS and SCC treated with 5-fluorouracil, imiquimod, electrodessication, curettage, photodynamic therapy, ablative lasers, or cryotherapy.

RESULTS

We included 186 studies describing treatment of 9,336 tumors. The recurrence rates of SCC and SCCIS following electrodessication with curettage (2.0%; 95% CI, 1.1%-3.0%) or cryotherapy with curettage (1.6%; 95% CI, 0.4%-2.8%) were lower than other treatments, such as photodynamic therapy (29.0%; 95% CI, 25.0%-33.0%), 5-fluorouracil (26.6%; 95% CI, 16.9%-36.4%), or imiquimod (16.1%; 95% CI, 10.3%-21.8%).

LIMITATIONS

Limitations include publication bias of mostly observational data and heterogeneity of treatment regimens.

CONCLUSION

Electrodessication and cryotherapy, in combination with curettage, are more effective than photodynamic therapy, 5-flurouracil, or imiquimod for treating SCCIS and SCC.

Case Report: Combined Intra-Lesional IL-2 and Topical Imiquimod Safely and Effectively Clears Multi-Focal, High Grade Cutaneous Squamous Cell Cancer in a Combined Liver and Kidney Transplant Patient

Cutaneous squamous cell carcinoma (cSCC) is the second most common non-melanoma skin cancer worldwide, with ever increasing incidence and mortality. While most patients can be treated successfully with surgical excision, cryotherapy, or radiation therapy, there exist a subset of patients with aggressive cSCC who lack adequate therapies. Among these patients are solid organ transplant recipients who due to their immunosuppression, develop cSCC at a dramatically increased rate compared to the normal population. The enhanced ability of the tumor to effectively undergo immune escape in these patients leads to more aggressive tumors with a propensity to recur and metastasize. Herein, we present a case of aggressive, multi-focal cSCC in a double organ transplant recipient to frame our discussion and current understanding of the immunobiology of cSCC. We consider factors that contribute to the significantly increased incidence of cSCC in the context of immunosuppression in this patient population. Finally, we briefly review current literature describing experience with localized therapies for cSCC and present a strong argument and rationale for consideration of an IL-2 based intra-lesional treatment strategy for cSCC, particularly in this immunosuppressed patient population.

Japanese Dermatological Association Guidelines: Outlines of Guidelines for Cutaneous Squamous Cell Carcinoma 2020

In consideration of the development of treatment options for squamous cell carcinoma (SCC), the Japanese Skin Cancer Society issued the first guidelines of SCC in 2007 and revised them in 2015. Here, we report the English version of the 2020 edition of the Japanese SCC guidelines. The first half of this article is an overview of SCC including actinic keratosis and Bowen's disease, and the second half discusses three clinical questions: (i) treatment of actinic keratosis; (ii) determination of the resection margin of the primary lesion; and (iii) treatment of radically incurable cases, as contemporary problems encountered in treating SCC. In these evaluations, all processes were implemented according to the Grading of Recommendations, Assessment, Development, Evaluation system. Also, items of recommendation concerning each clinical question were determined by a multidisciplinary expert panel consisting of dermatologists, plastic/reconstructive surgeons, radiologists, and oncologists through a comprehensive literature search and systematic reviews.

Tumor Clearance and Immune Cell Recruitment in UV-Induced Murine Squamous Cell Carcinoma Exposed to Ablative Fractional Laser and Imiquimod Treatment

BACKGROUND AND OBJECTIVES

Keratinocyte carcinoma (KC) is the most common cancer worldwide, and squamous cell carcinoma (SCC) is the second most frequent subtype. Ablative fractional laser (AFL)-assisted drug delivery significantly enhances the uptake of topically applied drugs. The objective of this study was to assess tumor response and perform a descriptive characterization of the local recruitment of immune cells and systemic immune mediator levels in an ultraviolet radiation (UVR)-induced murine SCC model after AFL treatment alone and combined with topical imiquimod.

STUDY DESIGN/MATERIALS AND METHODS

Immunocompetent hairless mice (C3·Cg/TifBomTac, n = 74) were irradiated with solar-simulated UVR until 3-mm SCCs developed. The mice were divided into four interventional groups: AFL alone, AFL + imiquimod, imiquimod alone, and untreated SCC controls. AFL was given as a single treatment, whereas imiquimod was applied daily until the mice were euthanized on Days 0, 2, 7, or 14. SCCs were photographed and measured (mm) to assess the therapeutic response. Skin samples were processed for histopathological and immunohistochemical analyses, as well as for flow cytometry. Cytokine expression changes in sera were analyzed using ELISpot cytokine arrays.

RESULTS

Treatment of mouse SCCs with AFL + imiquimod induced the most robust immune cell infiltration and the greatest proportion of tumor clearance compared to other interventions. Early innate immune cell infiltration was induced by AFL + imiquimod treatment as the number of neutrophils and macrophages had increased fourfold within 2 days of treatment initiation compared with untreated SCC control mice (P < 0.05). AFL treatment alone had a more limited effect, with a fourfold increase in neutrophils (P < 0.05) but no significant increase in the number of macrophages. Correspondingly, treatment with AFL + imiquimod had the greatest effects on the adaptive immune cell recruitment: CD4⁺ T-helper cells increased threefold at Day 7 compared with untreated SCCs (P = 0.0001) and, notably, cytotoxic CD8⁺ T cells increased 14-fold at Day 14 (P = 0.0112). In addition, FOXP3⁺ regulatory T cells (Tregs) increased 14-fold at Day 7 (P = 0.0026), suggesting the resolution of the inflammatory infiltration. AFL treatment alone induced a moderate immune cell infiltration (a twofold increase in CD4⁺ T-helper cells, P = 0.0200; a threefold increase in CD8⁺ T cells, P = 0.0100; and a 14-fold increase in FOXP3⁺ Tregs at Day 14, P = 0.0021), whereas imiquimod alone did not significantly increase cell counts. AFL + imiquimod treatment increased CXCL12 serum levels threefold at Day 14 (P = 0.0200).

CONCLUSION

AFL treatment alone and in combination with imiquimod induces substantial tumor clearance associated with local recruitment of innate and adaptive immune cells in UVR-induced murine SCCs. These results may provide a basis for new immunotherapeutic approaches to KC treatment.

Nonsurgical treatment of skin cancer with local delivery of bioadhesive nanoparticles

Keratinocyte-derived carcinomas, including squamous cell carcinoma (SCC), comprise the most common malignancies. Surgical excision is the therapeutic standard but is not always clinically feasible, and currently available alternatives are limited to superficial tumors. To address the need for a nonsurgical treatment for nodular skin cancers like SCC, we developed a bioadhesive nanoparticle (BNP) drug delivery system composed of biodegradable polymer, poly(lactic acid)-hyperbranched polyglycerol (PLA-HPG), encapsulating camptothecin (CPT). Nanoparticles (NPs) of PLA-HPG are nonadhesive NPs (NNPs), which are stealthy in their native state, but we have previously shown that conversion of the vicinal diols of HPG to aldehydes conferred NPs the ability to form strong covalent bonds with amine-rich surfaces. Herein, we show that these BNPs have significantly enhanced binding to SCC tumor cell surfaces and matrix proteins, thereby significantly enhancing the therapeutic efficacy of intratumoral drug delivery. Tumor injection of BNP-CPT resulted in tumor retention of CPT at ∼50% at 10 d postinjection, while CPT was undetectable in NNP-CPT or free (intralipid) CPT-injected tumors at that time. BNP-CPT also significantly reduced tumor burden, with a portion (∼20%) of BNP-CPT-treated established tumors showing histologic cure. Larger, more fully established PDV SCC tumors treated with a combination of BNP-CPT and immunostimulating CpG oligodeoxynucleotides exhibited enhanced survival relative to controls, revealing the potential for BNP delivery to be used along with local tumor immunotherapy. Taken together, these results indicate that percutaneous delivery of a chemotherapeutic agent via BNPs, with or without adjuvant immunostimulation, represents a viable, nonsurgical alternative for treating cutaneous malignancy.

Advances in non and minimal-invasive transcutaneous delivery of immunotherapy for cancer treatment

Cancer research has focused on figuring out what was the difference between cancer cells and the tissues within which cancer arose and developing targeted treatments for those differences. With FDA-approved treatments for more ten different cancers and more than thousand new clinical trials, immunotherapy has recently emerged as the most promising area of cancer research by improving efficacy and controlling the adverse effects. Transcutaneous delivery drug delivery offers a number of advantages for the patient because of not only its noninvasive and convenient nature but also factors such as avoidance of first-pass metabolism and prevention of gastrointestinal degradation. The purpose of this review was to highlight technological recent approaches to non and minimal-invasive delivery of immunotherapy for cancer treatment. Finally, some practical considerations and discussions for future studies in the field of transdermal immunomodulation are also included.

Photocarcinogenesis

Purpose of Review

Skin cancers account for more than 40% of all cancers in the USA and continue to rise in incidence. It is prudent to understand the current burden and pathogenesis of photocarcinogenesis and preventive measures.

Recent Findings

Insights into recently discovered mechanisms have paved way for potential targets for prevention and therapeutics. Nicotinamide has shown promising results as an oral chemopreventive agent. UVB affects the DHODH pathway of pyrimidine synthesis via STAT 3. DHODH inhibition by leflunomide may be a potential targeted chemoprevention strategy. A photolyase containing sunscreen, which repairs UV-damaged DNA, effectively reduced new precancerous lesions. Several antioxidants and anti-inflammatory agents including many phytochemicals ameliorate the process of photocarcinogenesis in preclinical and clinical studies, e.g., green tea polyphenols, Polypodium leucotomos extract, and Timosaponin A III. Diet can potentially affect skin cancer risk by its ability to modify oxidative stress and cell signaling pathways.

Summary

Photocarcinogenesis is a multi-step process. An in-depth understanding is instrumental in development of novel agents for prevention and treatment of skin cancers.

Field cancerization: Treatment

The goal of field cancerization treatment is to reduce the risk of developing keratinocyte carcinoma. Selecting the appropriate therapy depends on the degree of field cancerization and the number of invasive cutaneous squamous cell carcinomas. Other considerations include treatment efficacy, cost, side effects, and patient preference. Field therapies are preferred because they address clinically visible disease and subclinical atypia. However, lesion-directed therapies are useful for lesions that are more difficult to treat or those where a histologic diagnosis is required. Patients with extensive field cancerization benefit from a combination of field-directed and lesion-directed treatments. The second article in this continuing medical education series provides a framework to guide evidence-based decision making for field cancerization treatment.

Outcomes of Cutaneous Squamous Cell Carcinoma in the Head and Neck Region With Regional Lymph Node Metastasis: A Systematic Review and Meta-analysis

Importance

There is a need to summarize the available evidence and provide quantitative data of the most important prognostic factors for patients with metastatic cutaneous squamous cell carcinoma of the head and neck region with regional lymph node metastasis (McSCCHN).

Objective

To undertake a PRISMA-compliant systematic review and meta-analysis of all published studies on the risk factors for overall survival (OS), locoregional control (LRC), locoregional recurrence (LRR), and disease-specific survival (DSS) for patients with McSCCHN.

Data Sources

PubMed, CINAHL, and Embase were searched from 1946 to August 2018 for English-language articles.

Study Selection

Inclusion criteria were randomized clinical trials or observational studies reporting on at least 10 patients with McSCCHN; studies analyzing 1 defined risk factor; reporting OS, LRC, LRR, or DSS; and clinical follow-up of 1 year of more. For the final analysis we included risk factors that were analyzed for the same outcome in at least 3 studies. Of the 2923 articles screened, 21 articles met the inclusion criteria.

Data Extraction and Synthesis

PRISMA guidelines were used for abstracting the data. Two reviewers independently abstracted the data. Risk of bias was estimated with the Newcastle-Ottawa Scale. Meta-analysis was performed using the random-effects model. All analysis took place between January and October 2018.

Main Outcomes and Measures

The primary end point was OS. Secondary end points included LRC, LRR, and DSS.

Results

A total of 20 observational studies and 1 randomized clinical trial were identified, representing 3534 patients (some reviewed articles reported no demographic characteristics), and were included in the analysis. Significant risk factors associated with OS were immunosuppression (hazard ratio [HR] of death, 2.66; 95% CI, 2.26-3.13), extracapsular spread (HR, 1.90; 95% CI, 1.12-3.23), adjuvant radiotherapy (HR, 0.45; 95% CI, 0.27-0.78), lymph node ratio (HR, 1.91; 95% CI, 1.09-3.35), and advanced age (HR, 1.03; 95% CI, 1.00-1.07). Immunosuppression (HR, 3.82; 95% CI, 2.47-5.92) and adjuvant radiotherapy (HR, 0.52; 95% CI, 0.33-0.84) were also significant risk factors for DSS.

Conclusions and Relevance

Immunosuppressed patients and those with extracapsular extension have poor prognosis. Adjuvant radiotherapy is associated with an improvement in OS. These risk factors will assist with better risk stratification and may also help to inform future clinical trials.

Current Basal and Squamous Cell Skin Cancer Management

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Characterize basal and squamous cell carcinomas as low or high risk based on size, location, histology, and clinical features. 2. Understand appropriate surgical margins in low- and high-risk lesions, and other management options, including Mohs micrographic surgery, electrodissection and curettage, topical agents, cryotherapy, photodynamic therapy, and radiation therapy. 3. Discuss adjuvant therapies for locally advanced and metastatic disease, including radiation therapy, chemotherapy, and targeted therapies such as hedgehog pathway inhibitors. 4. Educate patients on preventive measures such as skin examinations, sun protection, oral retinoids, and oral nicotinamide (vitamin B3). 5. Devise a reconstructive plan once clear oncologic margins are obtained.

SUMMARY

With the growing incidence of basal and squamous cell carcinoma, there is an increasing demand for appropriate oncologic management and aesthetic reconstruction. The goal of this CME article is to provide a foundation of knowledge to accurately diagnose, stage, and treat nonmelanoma skin cancers. In addition, it provides the practicing plastic surgeon alternate tools for managing these skin lesions, including topical agents, destructive therapies, and radiation therapy. Lastly, reconstructive plans for selected soft-tissue defects are discussed.

Recent advances in field cancerization and management of multiple cutaneous squamous cell carcinomas

Cutaneous squamous cell carcinoma (SCC) is among the most common cancers in humans, and many patients with SCC will develop multiple tumors within their lifetime. The field cancerization concept, originally proposed over 60 years ago, hypothesized that multiple primary cancers may arise simultaneously and coexist with subclinical precursor lesions within a defined field. Genetic sequencing of SCC and precursor lesions has identified what may be the earliest clonal proliferations in SCC development and confirmed that field cancerization in the skin is mediated by ultraviolet radiation. For patients with multiple SCCs and severe actinic damage, treatment of precursor lesions within a cancerized field can decrease the risk of subsequent cancer development. Sunblock is an effective intervention for field cancerization, even in patients with established disease. There is now direct evidence that field therapy with topical 5-fluorouracil is effective in reducing the incidence of subsequent SCC, and there is indirect evidence suggesting that topical imiquimod, topical ingenol mebutate, and photodynamic therapy are similarly effective. There is limited direct evidence to show that systemic acitretin or nicotinamide can decrease incident SCC in patients with field cancerization. In this review, an approach to the management of patients with multiple SCCs and field cancerization is presented along with the rationale to support field-directed therapy.

Imiquimod in dermatology: an overview

Imiquimod is an immune response modifier commercially available as a 3.75 and 5% cream. Topical imiquimod stimulates the innate and adaptive immune responses and induces cytokine production. This allows its use for the treatment of a wide variety of benign and malignant skin conditions due to its potential antiviral, antitumor, and immunoregulatory effects. Currently, topical imiquimod is US Food and Drug Administration (FDA)-approved for the treatment of anogenital warts, actinic keratosis, and superficial basal cell carcinomas. However, it has also shown a beneficial effect in the treatment of many other skin disorders. In this review, we describe existing evidence on the mechanism of action of topical imiquimod, its FDA-approved indications, off-label uses, and side effects.

Immunocryosurgery - an effective combinational modality for Bowen's disease

Bowen's disease (BD) is widely treated with topical imiquimod or cryosurgery. The present single-center retrospective study reports on the application of standardized immunocryosurgery (cryosurgery during ongoing topical imiquimod) for the treatment of BD. Daily imiquimod 5% cream was applied on BD lesion and a 5 mm rim around it in 5-week treatment cycles; cryosurgery (liquid N₂ , open spray; 2 cycles, 15 second each) was performed at the end of the second week of each treatment cycle. Between 1/1/2009 and 31/12/2014 21 patients (mean age ± SD: 74.4 ± 8.0 years; 12 males) with 24 lesions (mean maximum diameter ± SD: 45.8 ± 50.9 mm; range: 9-200 mm) completed the protocol. The anatomic distribution of the lesions included face/scalp (Ν = 14), neck/trunk (Ν = 6), and extremities (Ν = 4). Twenty-one out of twenty-four lesions with diameter <80 mm cleared after one immunocryosurgery cycle, while the rest three tumors (with the largest diameters: 100, 180, 200 mm) required two treatment cycles for complete response (clearance rate: 100%). After a median follow-up of 24 months (range: 6-60 months) the overall effectiveness was 91.7%: 22/24 lesions remained in sustained complete remission. With the exception of a variable degree of hypopigmentation, the cosmetic outcome was satisfactory even for extensive lesions. Immunocryosurgery, is feasible and highly efficacious minimally-invasive treatment alternative for BD.

Plasmacytoid dendritic cell role in cutaneous malignancies

Plasmacytoid dendritic cells (pDCs) correspond to a specialized dendritic cell population that exhibit plasma cell morphology, express CD4, CD123, HLA-DR, blood-derived dendritic cell antigen-2 (BDCA-2), and Toll-like receptor (TLR)7 and TLR9 within endosomal compartments. Through their production of type I interferons (IFNs) and other pro-inflammatory cytokines, pDCs provide anti-viral resistance and link the innate and adaptive immunity by controlling the function of myeloid DCs, lymphocytes, and natural killer (NK) cells. While lacking from normal skin, pDCs are usually recruited to the skin in several cutaneous pathologies where they appear to be involved in the pathogenesis of several infectious, inflammatory/autoimmune, and neoplastic entities. Among the latter group, pDCs have the potential to induce anti-tumour immunity; however, the complex interaction of pDCs with tumor cells and their micro-environment appears to contribute to immunologic tolerance. In this review, we aim at highlighting the role played by pDCs in cutaneous malignancies with special emphasis on the underlying mechanisms.

Consensus for Nonmelanoma Skin Cancer Treatment, Part II: Squamous Cell Carcinoma, Including a Cost Analysis of Treatment Methods

BACKGROUND

Cutaneous squamous cell carcinoma (cSCC) is the second most common cancer in the United States. Cutaneous squamous cell carcinoma has an estimated incidence of more than 700,000 new cases per year and a 5% risk of metastasis.

OBJECTIVE

To provide clinicians with guidelines for the management of cSCC based on evidence from a comprehensive literature review and consensus among the authors.

MATERIALS AND METHODS

The authors conducted an extensive review of the medical literature on treatment methods for cSCC, taking into consideration cure rates, recurrence and metastatic rates, aesthetic and functional outcomes, and cost effectiveness of the procedures.

RESULTS

Surgical treatments provide the best outcomes for cSCC. Mohs micrographic surgery is a cost-effective procedure that affords the highest cure rate, maximal tissue preservation, and superior cosmetic outcomes. Nonsurgical methods may be used as a primary treatment for low-risk squamous cell carcinomas, but the cure rates are lower.

CONCLUSION

The cure rate remains the most important consideration in choosing the treatment method, but additional factors, such as the patient's general medical condition, psychosocial circumstances, the location of the tumor and cost effectiveness of the therapy should be considered. Mohs micrographic surgery remains the preferred treatment for high-risk tumors and tumors located in cosmetically sensitive areas.

A Comparative Study Examining the Management of Bowen's Disease in the United Kingdom and Australia

Background and Aim. The optimum management of Bowen's Disease (BD) is undefined. A review of current practice is required to allow the development of best practice guidelines. Methods. All BD cases, diagnosed in one UK centre and one Australian centre over a year (1 July 2012-30 June 2013), were analysed retrospectively. Patients with BD were identified from histopathology reports and their medical records were analysed to collect demographic data, site of lesion, and treatment used. Results. The treatment of 155 lesions from the UK centre and 151 lesions from the Australian centre was analysed. At both centres BD was most frequently observed on the face: UK had 70 (45%) lesions and Australia had 83 (55%) lesions (P = 0.08). The greatest number of lesions was managed by the plastic surgery department in the UK centre, 72 (46%), and the dermatology department in the Australian centre, 121 (80%). The most common therapy was surgical excision at both centres. Conclusions. In both UK and Australia, BD arises on sun-exposed sites and was most commonly treated with surgical excision despite a lack of robust evidence-based guidelines.

Advances in diagnosis and treatment of nonmelanoma skin cancer

The incidence of nonmelanoma skin cancer (NMSC) is rising. Research in the field of these tumors is aimed toward developing earlier and less invasive diagnostic methods and more effective, more accessible therapeutic options. Although there is much advancement in the diagnosis and treatment of NMSC, there are few literatures cataloging these developments. The aim of this review was to present the sensitivity and specificity of new imaging modalities, the dosing regimen and clearance rates of topical treatments, newer systemic treatment modalities, and discuss developments in the use of radiation as a mode of therapy. Recent developments in the diagnosis of NMSC include imaging modalities such as reflectance confocal microscopy, elastic scattering spectroscopy, and spectrophotometric intracutaneous analysis. Recent advances in the treatment of these tumors include systemic therapies such as epidermal growth factor receptor inhibitors, and topical immunomodulating drugs such as imiquimod. The progress in the diagnosis and treatment of these tumors is a gradual but fruitful growth. Scientists and clinicians alike must continue their exploration and study to address these tumors and, hopefully in the future, prevent their occurrence.

Bowenoid papulosis successfully treated with imiquimod 5% cream

A 24-year-old healthy Japanese female was diagnosed as having bowenoid papulosis in the genital area. The histopathological findings revealed acanthosis, papillomatosis, dyskeratotic cells and clumping cells with mild atypical nuclei. Human papillomavirus type 16 was detected in the lesion. The lesion was successfully treated with topical imiquimod 5% cream after 2 months. Imiquimod 5% cream is a potentially effective treatment modality for lesions that are difficult to treat with surgical excision.

Recurrent Bowen's disease of scalp treated with high dose rate surface mold brachytherapy: a case report and review of the literature

Our case is a 46-year-old female presenting to us with Bowen's disease of scalp since 5 years. Patient had failed topical therapy with 5% 5-florouracil, 0.1% tacrolimus and was intolerant to topical imiquimod. At presentation, she had 15 cm × 10 cm erythematous, hyperpigmented, crusted plaque with irregular border in the superior and lateral aspect of left side of scalp with extension in to forehead. Patient was treated with computed tomography based customized surface mold high dose rate brachytherapy with Iridium-192 to a dose of 35 Gy in 10 fractions (twice daily, 6 hours apart) over 5 days. Patient tolerated the treatment well and showed regression of the lesion with mild dermatitis at the end of treatment. Though dermatitis increased at 2 weeks, at 4 weeks post treatment there was near complete resolution of the lesion with adjacent alopecia. At 8 weeks after completion of the treatment, there was complete resolution of the lesion and patient was asymptomatic. Alopecia in the adjacent area has resolved and the skin pigmentation has begun. Patient is satisfied with both the disease control and the cosmetic outcome of the procedure. Our case report demonstrates successful application of surface mold high dose rate brachytherapy in the treatment of recurrent Bowen's disease of the scalp. Brachytherapy can play an important role in the management of recurrent malignant and premalignant diseases of the complex treatment sites like scalp and it's non-hesitant use should be encouraged in appropriately selected patients at the earliest.

Successful treatment of genital Bowen’s disease with imiquimod 5% cream

A 64-year-old Japanese woman was diagnosed as having Bowen’s disease on the vulva. The histopathological findings revealed papillomatosis, koilocytosis and clumping cells with atypical nuclei. Human papillomavirus DNA was not detected on polymerase chain reaction using consensus primers. The lesion was successfully treated with topical imiquimod 5% cream after two months. Histopathologically, no atypical cells were observed after treatment. Imiquimod can be a potential treatment modality for lesions that are difficult to treat with surgical excision.

Topical pharmacotherapy for skin cancer: part I. Pharmacology

Topical pharmacotherapy represents an effective alternative treatment for superficial skin cancer, primarily actinic keratoses and basal cell carcinomas. We provide an in-depth analysis of the pharmacologic aspects of available topical drugs for the treatment of primary skin tumors. In particular, we evaluate the mechanisms of action, formulations and indications, side effects, and contraindications of 5-fluorouracil, imiquimod, diclofenac, ingenol mebutate, and retinoids. Moreover, the characteristics of some investigational molecules (ie, resiquimod, piroxicam, dobesilate, and betulinic acid) are presented.

Topical pharmacotherapy for skin cancer: part II. Clinical applications

The purpose of the paper is to provide an in-depth, evidence-based analysis of the clinical use of topical treatments for skin cancer. A comprehensive review of topical drugs has been performed, including 5-fluorouracil, imiquimod, diclofenac, ingenol mebutate, retinoids, resiquimod, piroxicam, dobesilate, and betulinic acid. The evaluated studies were rated according to their level of evidence level (I-V), as indicated by recent guidelines for evidence-based medicine, The Oxford 2011 Levels of Evidence. Therapeutic response is generally related to tumor type, extent, and localization, and also to patient compliance. Careful patient selection is required in order to achieve the desired goal of complete tumor clearance.