Actinic keratosis is an early in situ squamous cell carcinoma: a proposal for reclassification

Actinic keratosis metrics

Actinic keratosis (AK) is a common precancerous skin condition predominantly affecting older males with fair skin and significant UV exposure. The clinical significance of AK is related to its potential for malignant transformation and progression to squamous cell carcinoma (SCC). Accurate diagnosis of AK is essential for adequate treatment, evaluation of therapeutic efficacy, and mitigating the risk of developing SCC. However, clinician variability due to the subjective nature of current diagnostic tools presents significant challenges to achieving consistent and reliable AK diagnoses. Thus, there is no universally accepted standard for measuring AK.This review evaluates current methods for evaluating and diagnosing AK, focusing on clinician variability through inter- and intraobserver agreement. Eight peer-reviewed studies investigating the reliability of various approaches for AK evaluation show substantial variability in interobserver or intraobserver agreement, with most methods demonstrating only slight to moderate reliability. Some suggest that consensus discussions and simplified rating scales can modestly improve diagnostic reliability. However, remaining variability and the lack of a universally accepted standard for measuring AK underscore the need for more robust and standardized diagnostic and evaluation methods.The review emphasizes the need for improved diagnostic tools and standardized methods to enhance the accuracy and reliability of AK assessments. It also proposes applying a novel examination approach using 1,3-dihydroxyacetone (DHA) staining which may improve the visualization and identification of AK lesions. Advancements in these areas have significant potential, promising better clinical practices and patient outcomes in AK management.

Actinic keratosis: Current challenges and unanswered questions

Actinic keratoses (AK) are common skin lesions associated with chronic exposure to sun. They are believed to be precursors of malignancy as they potentially may progress to invasive squamous cell carcinomas. The goal of current therapies is to reduce the number of AK and to prevent future cancer development. This review aims at providing an overview of the hallmarks of AK and skin field cancerization. We discuss epidemiology trends, risk factors and the state of the art and evidence of the current treatments. We review key figures of AK prevalence from different countries with regard to skin cancer risk and the associated economic burden of AK. We discuss the mutational status in AK lesions and the difficulties encountered by clinicians in evaluating AK visible and invisible lesions, referring to the concept of field cancerization. Based on a systematic literature review, we further evaluate the available treatment options. The presence of subclinical skin alterations in the periphery of visible AK lesions has gained a particular attention as those non-visible lesions are known to contain the same genetic changes as those found in the AK lesions themselves, prompting the concept of 'field cancerization'. Therefore, AK treatment guidelines now recognize the importance of treating the field in patients with AK. A recent systematic literature review and network meta-analysis showed that 5-FU interventions were associated with the best efficacy and a satisfactory acceptability profile compared with other field-directed therapies used in the treatment of AK. Although AK are considered quite common, they lack an accurate descriptive definition and conclusive epidemiologic data. Limited public awareness is a barrier to early and effective treatment, including prevention strategies. While different treatment options are available, there is still a limited understanding of long-term outcomes of treatment as measured by recurrence of cancer prevention.

European consensus-based interdisciplinary guideline for diagnosis, treatment and prevention of actinic keratoses, epithelial UV-induced dysplasia and field cancerization on behalf of European Association of Dermato-Oncology, European Dermatology Forum, European Academy of Dermatology and Venereology and Union of Medical Specialists (Union Européenne des Médecins Spécialistes)

A collaboration of multidisciplinary experts from the European Association of Dermato-Oncology, the European Dermatology Forum, the European Academy of Dermatology and Venereology, and the European Union of Medical Specialists was formed to develop European recommendations on AK diagnosis and treatment, based on current literature and expert consensus. This guideline addresses the epidemiology, diagnostics, risk stratification and treatments in immunocompetent as well as immunosuppressed patients. Actinic keratoses (AK) are potential precursors of cutaneous squamous cell carcinoma (cSCC) and display typical histopathologic and immunohistochemical features of this malignancy in an early stage. They can develop into cSSC in situ and become invasive in a low percentage of cases. AK is the most frequent neoplasia in white populations, frequently occurring within a cancerous field induced by ultraviolet radiation. Since it cannot be predicted, which lesion will progress to cSCC and when treatment is usually recommended. The diagnosis of AK and field cancerization is made by clinical examination. Dermatoscopy, confocal microscopy, optical coherence tomography or line-field confocal-OCT can help in the differential diagnosis of AK and other skin neoplasms. A biopsy is indicated in clinically and/or dermatoscopically suspicious and/or treatment-refractory lesions. The choice of treatment depends on patients' and lesion characteristics. For single non-hyperkeratotic lesions, the treatment can be started upon patient's request with destructive treatments or topical treatments. For multiple lesions, field cancerization treatment is advised with topical treatments and photodynamic therapy. Preventive measures such as sun protection, self-examination and repeated field cancerization treatments of previously affected skin areas in high-risk patients are advised.

Diagnosis and therapy of actinic keratosis

Actinic keratosis (AK) is considered a chronic and recurring in situ skin neoplasia, with a possible transformation into invasive squamous cell carcinoma (SCC). Among others, predominant risk factors for development of AK are UV-light exposure and immunosuppression. Basal epidermal keratinocyte atypia (AK I) and proliferation (PRO score) seem to drive malignant transformation, rather than clinical appearance of AK (Olsen I-III). Due to the invasiveness of punch biopsy, those histological criteria are not regularly assessed. Non-invasive imaging techniques, such as optical coherence tomography (OCT), reflectance confocal microscopy (RCM) and line-field confocal OCT (LC-OCT) are helpful to distinguish complex cases of AK, Bowen's disease, and SCC. Moreover, LC-OCT can visualize the epidermis and the papillary dermis at cellular resolution, allowing real-time PRO score assessment. The decision-making for implementation of therapy is still based on clinical risk factors, ranging from lesion- to field-targeted and ablative to non-ablative regimens, but in approximately 85% of the cases a recurrence of AK can be observed after a 1-year follow-up. The possible beneficial use of imaging techniques for a non-invasive follow-up of AK to detect recurrence or invasive progression early on should be subject to critical evaluation in further studies.

Diagnose und Therapie aktinischer Keratosen

Actinic keratosis (AK) is considered a chronic and recurring in situ skin neoplasia, with a possible transformation into invasive squamous cell carcinoma (SCC). Among others, predominant risk factors for development of AK are UV-light exposure and immunosuppression. Basal epidermal keratinocyte atypia (AK I) and proliferation (PRO Score) seem to drive malignant turnover, rather than clinical appearance of AK (Olsen I-III). Due to the invasiveness of punch biopsy, those histological criteria are not regularly assessed. Non-invasive imaging techniques, such as optical coherence tomography (OCT), reflectance confocal microscopy (RCM) and line-field confocal OCT (LC-OCT) are helpful to distinguish complex cases of AK, Bowen's disease and SCC. Moreover, LC-OCT can visualize the epidermis and the papillary dermis at cellular resolution, allowing real-time PRO Score assessment. The decision-making for implementation of therapy is still based on clinical risk factors, ranging from lesion- to field-targeted and ablative to non-ablative regimes, but in approximately 85% of the cases a recurrence of AK can be observed after a 1-year follow-up. The possible beneficial use of imaging techniques for a non-invasive follow-up of AK to detect recurrence or invasive progression early on should be subject to critical evaluation in further studies.

Epidemiological and clinical analysis of exposure-related factors in non-melanoma skin cancer: A retrospective cohort study

BACKGROUND

The incidence of non-melanoma skin cancers (NMSCs) increased over last decades, probably due to environmental concerns or to the increase of frail patients with age related comorbidities. Currently, the relationship of increasing global skin cancer rates with increased ultraviolet radiations (UVRs) resulting from stratospheric ozone depletion, global warming, and air pollution from fossil-fuel combustion.

AIMS

We conducted a retrospective epidemiological study including 546 NMSC patients managed at the Dermatology Unit of the Tor Vergata Hospital to highlight different trends of sun exposure or different comorbidities.

METHODS

Descriptive and inferential statistical analyses were performed to evidence differences between continous variable and Spearman rank test for dicotomical variables. Charlson Comorbidity Index was calculated to obtain the 10-years survival rate in order to identify the mean comorbidity burden of our patients.

RESULTS

Considering patients with comorbidities (73.81%), actinic keratoses (AKs) was the most frequent lesion. In patients with a history of previous melanoma, basal cell carcinoma (BCC) was predominant (ANOVA test, p < 0.05) with a statistically significant correlation (rho = 0.453; p < 0.01). Squamous cell carcinoma (SCC) showed a higher rate in arterial hypertension patients, followed by the chronic heart failure and hematologic neoplasms (60%, 29.7% and 32.1%, respectively) groups. Men were more affected than women, representing 61.54% of patients. Chronic sun exposure is directly correlated with SCC rho = 0.561; p < 0.01), whereas BCC correlated with a history of sunburns (rho = 0.312; p < 0.05).

CONCLUSIONS

History of photo-exposition had an important role on NMSC development especially for work or recreational reasons. Sex, age, and presence of comorbidities influenced different NMSC types. BCC was more frequent in younger patients, associated with melanoma and sunburns. The presence of SCC is associated with older patients and the hypertension group. AKs were diagnosed predominantly in oldest men, with a chronic sun-exposure history, and hematologic neoplasms group.

Line-field confocal optical coherence tomography in dermato-oncology: A literature review towards harmonized histopathology-integrated terminology

Non-invasive diagnostics like line-field confocal optical coherence tomography (LC-OCT) are being implemented in dermato-oncology. However, unification of terminology in LC-OCT is lacking. By reviewing the LC-OCT literature in the field of dermato-oncology, this study aimed to develop a unified terminological glossary integrated with traditional histopathology. A PRISMA-guided literature-search was conducted for English-language publications on LC-OCT of actinic keratosis (AK), keratinocyte carcinoma (KC), and malignant melanoma (MM). Study characteristics and terminology were compiled. To harmonize LC-OCT terminology and integrate with histopathology, synonymous terms for image features of AK, KC, and MM were merged by two authors, organized by skin layer and lesion-type. A subset of key LC-OCT image-markers with histopathological correlates that in combination were typical of AK, squamous cell carcinoma in situ (SCCis), invasive squamous cell carcinoma (SCC), basal cell carcinoma (BCC), and MM in traditional histopathology, were selected from the glossary by an experienced dermatopathologist. Seventeen observational studies of AK (7 studies), KC (13 studies), MM (7 studies) utilizing LC-OCT were included, with 117 terms describing either AK, KC, or MM. These were merged to produce 45 merged-terms (61.5% reduction); 5 assigned to the stratum corneum (SC), 23 to the viable epidermis, 2 to dermo-epidermal junction (DEJ) and 15 to the dermis. For each lesion, mandatory key image-markers were a well-defined DEJ and presence of mild/moderate but not severe epidermal dysplasia for AK, severe epidermal dysplasia and well-defined DEJ for SCCis, interrupted DEJ and/or dermal broad infiltrative strands for invasive SCC, dermal lobules connected and/or unconnected to the epidermis for BCC, as well as single atypical melanocytes and/or nest of atypical melanocytes in the epidermis or dermis for MM. This review compiles evidence on LC-OCT in dermato-oncology, providing a harmonized histopathology-integrated terminology and key image-markers for each lesion. Further evaluation is required to determine the clinical value of these findings.

Digitally Enhanced Methods for the Diagnosis and Monitoring of Treatment Responses in Actinic Keratoses: A New Avenue in Personalized Skin Care

Non-melanocytic skin cancers represent an important public health problem due to the increasing incidence and the important local destructive potential. Thus, the early diagnosis and treatment of precancerous lesions (actinic keratoses) is a priority for the dermatologist. In recent years, non-invasive skin imaging methods have seen an important development, moving from simple observational methods used in clinical research, to true diagnostic and treatment methods that make the dermatologist's life easier. Given the frequency of these precancerous lesions, their location on photo-exposed areas, as well as the long treatment periods, with variable, imprecise end-points, the need to use non-invasive imaging devices is increasingly evident to complete the clinical observations in the diagnosis and treatment of these lesions, with the aim of increasing accuracy and decreasing the adverse effects due to long treatment duration. This is the first review that brings together all skin imaging methods (dermoscopy, reflectance confocal microscopy, ultrasonography, dermoscopy-guided high frequency ultrasonography, and optical coherence tomography) used in the evaluation of actinic keratoses and their response to different treatment regimens.

Single-cell sequencing highlights heterogeneity and malignant progression in actinic keratosis and cutaneous squamous cell carcinoma

Cutaneous squamous cell carcinoma (cSCC) is the second most frequent of the keratinocyte-derived malignancies with actinic keratosis (AK) as a precancerous lesion. To comprehensively delineate the underlying mechanisms for the whole progression from normal skin to AK to invasive cSCC, we performed single-cell RNA sequencing (scRNA-seq) to acquire the transcriptomes of 138,982 cells from 13 samples of six patients including AK, squamous cell carcinoma in situ (SCCIS), cSCC, and their matched normal tissues, covering comprehensive clinical courses of cSCC. We identified diverse cell types, including important subtypes with different gene expression profiles and functions in major keratinocytes. In SCCIS, we discovered the malignant subtypes of basal cells with differential proliferative and migration potential. Differentially expressed genes (DEGs) analysis screened out multiple key driver genes including transcription factors along AK to cSCC progression. Immunohistochemistry (IHC)/immunofluorescence (IF) experiments and single-cell ATAC sequencing (scATAC-seq) data verified the expression changes of these genes. The functional experiments confirmed the important roles of these genes in regulating cell proliferation, apoptosis, migration, and invasion in cSCC tumor. Furthermore, we comprehensively described the tumor microenvironment (TME) landscape and potential keratinocyte-TME crosstalk in cSCC providing theoretical basis for immunotherapy. Together, our findings provide a valuable resource for deciphering the progression from AK to cSCC and identifying potential targets for anticancer treatment of cSCC.

Preliminary Evidence of Efficacy, Safety, and Treatment Satisfaction with Tirbanibulin 1% Ointment: A Clinical Perspective on Actinic Keratoses

BACKGROUND

Actinic keratosis is a common precancerous skin lesion that can progress into invasive squamous cell carcinomas. Many topical treatments for actinic keratoses often have poor tolerability and prolonged duration. Tirbanibulin is a novel synthetic drug with potent antitumor and antiproliferative activities.

METHODS

We conducted a single-center, prospective and observational study using tirbanibulin ointment on a 25 cm2 area for 5 consecutive days on 30 participants with AKs on the face or scalp. They were followed for at least 57 days to assess the safety profile and efficacy of the drug as well as treatment satisfaction. We evaluated six signs of local skin reaction (LSR): erythema, scaling, crusting, swelling, blisters/pustules, and erosions/ulcerations, grading the severity as mild, moderate, or severe. The effectiveness was evaluated both clinically and dermoscopically. The treatment satisfaction was assessed using the Treatment Satisfaction Questionnaire for Medication (TSQM 1.4).

RESULTS

On day 57, 70% of the patients showed a complete clinical and dermoscopic response. The highest scores obtained from the TSQM 1.4 were more evident in the convenience and side effects domains. Most LSRs, including erythema (83.3%), scaling (30%), and swelling (3.3%), occurred on day 8 but resolved spontaneously.

CONCLUSION

Tirbanibulin is a viable therapeutic option with a short regimen treatment and good tolerability, which favors therapy adherence.

Innovation in Actinic Keratosis Assessment: Artificial Intelligence-Based Approach to LC-OCT PRO Score Evaluation

Actinic keratosis (AK) is a common skin cancer in situ that can progress to invasive SCC. Line-field confocal optical coherence tomography (LC-OCT) has emerged as a non-invasive imaging technique that can aid in diagnosis. Recently, machine-learning algorithms have been developed that can automatically assess the PRO score of AKs based on the dermo-epidermal junction's (DEJ's) protrusion on LC-OCT images. A dataset of 19.898 LC-OCT images from 80 histologically confirmed AK lesions was used to test the performance of a previous validated artificial intelligence (AI)-based LC-OCT assessment algorithm. AI-based PRO score assessment was compared to the imaging experts' visual score. Additionally, undulation of the DEJ, the number of protrusions detected within the image, and the maximum depth of the protrusions were computed. Our results show that AI-automated PRO grading is highly comparable to the visual score, with an agreement of 71.3% for the lesions evaluated. Furthermore, this AI-based assessment was significantly faster than the regular visual PRO score assessment. The results confirm our previous findings of the pilot study in a larger cohort that the AI-based grading of LC-OCT images is a reliable and fast tool to optimize the efficiency of visual PRO score grading. This technology has the potential to improve the accuracy and speed of AK diagnosis and may lead to better clinical outcomes for patients.

Tissue memory relies on stem cell priming in distal undamaged areas

Epithelial cells that participated in wound repair elicit a more efficient response to future injuries, which is believed to be locally restricted. Here we show that cell adaptation resulting from a localized tissue damage has a wide spatial impact at a scale not previously appreciated. We demonstrate that a specific stem cell population, distant from the original injury, originates long-lasting wound memory progenitors residing in their own niche. Notably, these distal memory cells have not taken part in the first healing but become intrinsically pre-activated through priming. This cell state, maintained at the chromatin and transcriptional level, leads to an enhanced wound repair that is partially recapitulated through epigenetic perturbation. Importantly wound memory has long-term harmful consequences, exacerbating tumourigenesis. Overall, we show that sub-organ-scale adaptation to injury relies on spatially organized memory-dedicated progenitors, characterized by an actionable cell state that establishes an epigenetic field cancerization and predisposes to tumour onset.

Transcriptomic Study on Human Skin Samples: Identification of Two Subclasses of Actinic Keratoses

Actinic keratoses (AKs) are sun-damaged skin areas that affect 20% of the European adult population and more than 50% of people aged 70 years and over. There are currently no clinical or histological features allowing us to identify to which clinical class (i.e., regression or progression) an AK belongs. A transcriptomic approach seems to be a robust tool for AK characterization, but there is a need for additional studies, including more patients and elucidating the molecular signature of an AK. In this context, the present study, including the largest number of patients to date, is the first aiming at identifying biological features to objectively distinguish different AK signatures. We highlight two distinct molecular profiles: AKs featuring a molecular profile similar to squamous cell carcinomas (SCCs), which are called "lesional AKs" (AK_Ls), and AKs featuring a molecular profile similar to normal skin tissue, which are called "non-lesional AKs" (AK_NLs). The molecular profiles of both AK subclasses were studied, and 316 differentially expressed genes (DEGs) were identified between the two classes. The 103 upregulated genes in AK_L were related to the inflammatory response. Interestingly, downregulated genes were associated with keratinization. Finally, based on a connectivity map approach, our data highlight that the VEGF pathway could be a promising therapeutic target for high-risk lesions.

FGFR2c Upregulation Contributes to Cancer-Associated Fibroblast Program Activation and to Enhanced Autophagy in Actinic Keratosis-Derived Dermal Fibroblasts: A Possible Role in Precancerous Cell/Stromal Cell Crosstalk

Actinic keratosis (AK) is a preneoplastic skin disorder which can rapidly progress to cutaneous squamous cell carcinomas (SCCs). In light of our previous findings, indicating a possible oncogenic role of the mesenchymal isoform of FGFR2 (FGFR2c) aberrantly expressed in AK keratinocytes, we analyzed the possible tumor-promoting role of this receptor in the stromal AK counterpart in this work. Molecular analysis showed that, particularly in early AK lesions, FGFR2c dermal upregulation is accompanied by the downregulation of the cancer-associated fibroblasts (CAF) transcription repressor CSL, the upregulation of the CAF activator ULK3, and the consequent CAF gene induction. Immunofluorescence and molecular analysis, coupled with silencing approaches by siRNA, applied on primary cultures of KIN I-derived fibroblasts, indicated that FGFR2c upregulation contribute to CAF signature and the increased autophagy in response to FGF2. Magnetic bead-based multiplex assay, combined with FGFR2 signaling shut-off approaches, indicated that, especially in response to FGF2, IL-6 secretion could depend on FGFR2c high expression and signaling, suggesting the possible establishment of FGFR2c-dependent secretory autophagy, contributing to tumor-promoting factor release. Overall, our results identified FGFR2c as a signaling molecule involved in controlling precancerous/stromal cell oncogenic crosstalk, pointing to this receptor as a possible early molecular marker predictive for AK’s rapid malignant progression.

Basal Proliferation and Acantholysis May Represent Histological High-Risk Factors for Progression into Invasive Squamous Cell Carcinoma: A Comparison Study in Solid Organ Transplant Recipients and Matched Immunocompetent Patients

Histological risk factors of AKs cannot be directly determined. Recent studies indicate that AKs restricted to the lower third of the epidermis (AK I), with marked basal proliferation (PRO III) and acantholysis, are associated with an increased risk of progression to invasive squamous cell carcinoma (iSCC). To confirm the aforementioned histological risk factors, this study compared AKs from solid organ transplant recipients (sOTRs), known to carry an up to 250-fold higher risk for progression into iSCC, to a matched immunocompetent control group (ICG). In total, 111 AKs from 43 sOTRs showed more AKs (n = 54, 48.7%) graded as AK I compared to 35 AKs (31.5%) in the ICG (p = 0.009). In line with these findings, 89 AKs (80.2%) from sOTRs showed pronounced basal proliferation (PRO III) compared to 37 AKs (33.3%) in the ICG (p < 0.0001). Acantholysis was more frequent in sOTRs than the ICG (59.5% vs. 32.4%, p < 0.0001) and more frequently associated with advanced basal proliferation (p < 0.0001). In conclusion, this study showed that acantholytic AKs graded as AK I and PRO III are predominantly found in a population at high risk of iSCC. Thus, AKs with marked basal proliferation and acantholysis should be assumed to be histological high-risk factors for the progression into iSCC.

Topical Treatment of Actinic Keratosis and Metalloproteinase Expression: A Clinico-Pathological Retrospective Study

Actinic keratosis is an intraepithelial proliferation of atypical keratinocytes that could progress into invasive squamous cell carcinoma. Most evidence suggests an important role of the dermal matrix metalloproteinases in the progression of atypical skin epithelial lesions. We evaluated the clinical efficacy of three different therapeutic modalities (a medical device containing 0.8% piroxicam cream and 50+ sunscreen, photodynamic therapy, and ingenol mebutate gel) to treat suspicious actinic keratoses, which were biopsied for histopathological examination and then analyzed for the expression of matrix metalloproteinases by immunohistochemistry. Clinical, dermoscopic, and reflectance confocal microscopy evaluations revealed a gradual decrease in all standard scores validated for actinic keratosis assessment at the end of the treatments. From a histopathological point of view, we documented the substantial restoration of normal skin architecture, while the immunohistochemical evaluation of matrix metalloproteinases showed a reduction in expression in the treated skin lesions compared to the baseline. As actinic keratoses are considered the precursors of squamous cell carcinoma, their treatment is crucial to prevent the development of a more aggressive disease. Our study monitored the evolution of actinic keratoses subjected to three different topical therapies, with the value of correlating clinical and histopathological findings. Moreover, as the matrix metalloproteinases are largely recognized factors involved in the pathogenesis and evolution of actinic keratosis to squamous cell carcinoma, the demonstration by immunohistochemistry of a reduction in their expression after the treatments adds new valuable concern to the field.

The Role and Effectiveness of Photodynamic Therapy on Patients With Actinic Keratosis: A Systematic Review and Meta-Analysis

Actinic keratoses (AKs) are the most common neoplastic lesions and are recognized as a precursor to squamous cell skin cancer. Photodynamic therapy (PDT) is a therapeutic option for multiple AKs in line with field cancerization. The aim of this study was to assess the effectiveness of PDT on patients with AKs using a meta-analysis, in order to evaluate the possible superiority of one treatment over the others. For this purpose, the PubMed, MEDLINE, Scopus, OVID, Science Direct, British Journal of Dermatology, Research Gate, and Embase databases were searched in March 2022. The search terms used were 'photodynamic therapy' and 'actinic keratosis'. We utilized the random-effects meta-analysis model to compare methyl aminolevulinate PDT (MAL-PDT) and the combination of a nanoscale-lipid vesicle formulation with the prodrug 5-aminolevulinic acid (BF-200 ALA) on a complete response (CR) of the lesions. Our meta-analysis indicated that the comparison of BF-200 ALA versus MAL-PDT showed marginally higher CRs than MAL-PDT.

Clinical and histopathologycal study of actinic keratosis treatment with photodynamic therapy VS 5-fluorouracil in face cancerization field

Actinic keratosis (AK) is one of the most frequent pathologies in clinical practice. The prevalence varies according to the area of incidence and age. Approximately 10% of the prevalence of AK occurs at 30 years of age and rises to 80% at 70 years of life. This study conducted a split-face analysis based on Photodynamic Therapy (MALA-PDT) and 5-fluorouracil (5-FU) treatments in patients with AK. Clinical and histopathological studies evaluated each treatment's efficiency and side effects. Six patients were recruited between 50 and 70 years of age for this. MALA-PDT was applied on the right side of the face. A biodistribution time of 2 hours, a dose of light of 36 J / cm² (20 min irradiation), a spot for photoirradiation with a total area of 100 cm², and a wavelength of 635 nm were used. (LINCE equipment MMOPTICS-Brazil). By fluorescence diagnosis, clinical and subclinical AK lesions were evidenced in the area called the "cancerization field." Two cycles of MALA-PDT were performed on each patient, and 5-FU was applied twice daily for 15 days. A 2-month follow-up post-MALA-PDT and post-5-FU was carried out. The treatment based on 5-Flu and MALA-PDT clinically shows the same response, but MALA-PDT is less aggressive than 5-FU. The treatment of AK based on MALA-PDT is a practical, cheap, and easy-to-use technique.

Method of Assessing Skin Cancerization and KeratosesTM (MASCK™): development and photographic validation in multiple anatomical sites of a novel assessment tool intended for clinical evaluation of patients with extensive skin field cancerization

BACKGROUND

A range of 'field-directed' treatments is available for the management of extensive skin field cancerization (ESFC), but to date, the only validated objective quantitative tools are limited to assessment of actinic keratoses (AKs) affecting the head.

AIMS

To develop a versatile quantitative instrument for objective clinical assessment of ESFC and perform initial internal validation across multiple anatomical zones.

METHODS

The study comprised instrument development, pilot testing and instrument refinement and two rounds of reliability and inter-rater validation testing. The study was noninterventional and used a convenience sample of de-identified patient photographs selected based on preset criteria. An expert panel developed the instrument and scoring system via a modified Delphi voting process. A sample of 16 healthcare professionals from multiple specialties undertook the pilot testing, and a panel of seven dermatologists were involved in validation testing. Validation was determined by assessment of overall inter-rater agreement using Gwet chance-corrected agreement coefficients (ACs).

RESULTS

The instrument produced, called the Method for Assessing Skin Cancer and Keratoses™ (MASCK™), comprises the Skin Field Cancerization Index (SFCIndex), derived from area of skin involvement and AKs (number and thickness), a global assessment score and a cancer-in-zone score, and uses Likert scales for quantitative scoring. The SFCIndex is a composite score comprising the number and thickness of AKs multiplied by area of skin involvement. ACs for the SFCIndex components, the overall SFCIndex score and the global assessment score were > 0.80 (rated 'almost perfect') while the AC for the cancer-in-zone metric was lower (0.33, rated 'fair'). Internal consistency was demonstrated via positive correlation between the overall SFCIndex score and the global assessment score.

CONCLUSIONS

Our study found near-perfect agreement in inter-rater reliability when using MASCK to assess the severity of ESFC in multiple anatomical sites. Further validation of this novel instrument is planned to specifically assess its reliability, utility and feasibility in clinical practice.

Targeting Microenvironment of Melanoma and Head and Neck Cancers in Photodynamic Therapy

Background:

Photodynamic therapy (PDT), in comparison to other skin cancers, is still far less effective for melanoma, due to the strong absorbance and the role of melanin in cytoprotection. The tumour microenvironment (TME) has a significant role in tumour progression, and the hypoxic TME is one of the main reasons for melanoma progression to metastasis and its resistance to PDT. Hypoxia is also a feature of solid tumours in the head and neck region that indicates negative prognosis.

Objective:

The aim of this study was to individuate and describe systematically the main strategies in targeting the TME, especially hypoxia, in PDT against melanoma and head and neck cancers (HNC), and assess the current success in their application.

Methods:

PubMed was used for searching, in MEDLINE and other databases, for the most recent publications on PDT against melanoma and HNC in combination with the TME targeting and hypoxia.

Results:

In PDT for melanoma and HNC, it is very important to control hypoxia levels, and amongst the different approaches, oxygen self-supply systems are often applied. Vascular targeting is promising, but to improve it, optimal drug-light interval, and formulation to increase the accumulation of the photosensitiser in the tumour vasculature, have to be established. On the other side, the use of angiogenesis inhibitors, such as those interfering with VEGF signalling, is somewhat less successful than expected and needs to be further investigated.

Conclusion:

The combination of PDT with immunotherapy by using multifunctional nanoparticles continues to develop and seems to be the most promising for achieving a complete and lasting antitumour effect.

Early clinical response to 5-fluorouracil 0.5% and salicylic acid 10% topical solution in the treatment of actinic keratoses of the head: an observational study

BACKGROUND

Actinic keratosis is one of the most common dermatological disorders. A new topical solution, constituted by 0.5% 5-fluorouracil and 10% salicylic acid (Actikerall, Almirall) has been introduced in the treatment pipeline of non-hyperkeratotic actinic keratoses of the head and neck.

PATIENTS AND METHODS

We analyzed in an observational prospective clinical study the short-term treatment effectiveness of 5-fluorouracil and salicylic acid on face and scalp actinic keratoses of grade 1 and 2 of forty patients. Efficacy assessment was performed by clinical dermatological examination, collecting color photographs, calculating AKASI score, and by means of dermoscopy for each target lesion at every visit.

RESULTS

AKASI score decreased from an initial score of 3.3 to a final score of 0.9. At week 4, we were able to record a complete clearance of 50% of the treated lesions and a partial clearance of 28%. At the end of 12 weeks, 84% of the total lesions showed complete clearance, while 8% had partial clearance.

CONCLUSIONS

5-fluorouracil and salicylic acid topical solution is effective in the treatment of mild to moderate actinic keratoses. In the future, further studies are needed to evaluate the chance of adjusting drug dosage according to patients' and actinic keratoses features.

Spontaneous regression rates of actinic keratosis: a systematic review and pooled analysis of randomized controlled trials

Actinic keratosis (AK) are precancerous lesions of the skin which may progress to invasive squamous cell carcinoma. However, single lesions may also persist or even regress and heal spontaneously. Until now, evidence on the natural course of AK including spontaneous regression is limited. We aimed to synthesize regression rates of AK. We performed a systematic literature research in Medline, Embase, and CENTRAL for eligible trials until 3rd March 2020. Spontaneous regression rates were pooled using a random-effects model to calculate pooled proportions of participant-specific and lesion-specific complete clearance rates reported for the placebo arms of randomized controlled trials. Subgroup analyses were performed to dissect differences according to the type of placebo, immunocompetence of the participants, and localization of the lesions. Data from 38 records was included. The pooled participant-specific clearance rate was 8% (95% CI 6–10%, I² = 71%) while the lesion-specific clearance rate was 23% (95% CI 16–31%, I² = 97%). The highest participant- and lesion-specific clearance rates were achieved 12 weeks after the end of treatment (12% and 33%, respectively). Subgroup analysis revealed participant- as well as lesion-specific clearance rates of 0% for organ transplant recipients (OTR). We conclude that only a few participants achieve complete regression of their AK without any active treatment. Besides, the results underline that lesion clearance without active treatment is unlikely in OTR. Thus, early and consequent treatment of AK is recommended. Special attention should be paid when treating AK of OTR.

Skin cancer, including related pathways and therapy and the role of luteolin derivatives as potential therapeutics

Cutaneous malignant melanoma is the fastest growing and the most aggressive form of skin cancer that is diagnosed. However, its incidence is relatively scarce compared to the highest mortality rate of all skin cancers. The much more common skin cancers include nonmelanoma malignant skin cancers. Moreover, over the past several decades, the frequency of all skin cancers has increased much more dynamically than that of almost any other type of cancer. Among the available therapeutic options for skin cancers, chemotherapy used immediately after the surgical intervention has been an essential element. Unfortunately, the main problem with conventional chemopreventive regimens involves the lack of response to treatment and the associated side effects. Hence, there is a need for much more effective anticancer drugs. Correspondingly, the targeted alternatives have involved phytochemicals, which are safer chemotherapeutic agents and exhibit competitive anticancer activity with high therapeutic efficacy. Among polyphenolic compounds, some flavonoids and their derivatives, which are mostly found in medicinal plants, have been demonstrated to influence the modulation of signaling pathways at each stage of the carcinogenesis process, which is also important in the context of skin cancers. Hence, this review focuses on an exhaustive overview of the therapeutic effects of luteolin and its derivatives in the treatment and prevention of skin cancers. The bioavailability and structure–activity relationships of luteolin derivatives are also discussed. This review is the first such complete account of all of the scientific reports concerning this particular group of natural compounds that target a specific area of neoplastic diseases.

Exposome and Skin. Part 2. The Influential Role of the Exposome, Beyond UVR, in Actinic Keratosis, Bowen's Disease and Squamous Cell Carcinoma: A Proposal

Actinic keratosis (AK) is the main risk factor for the development of cutaneous invasive squamous cell carcinoma (SCC). It represents the first sign of severe chronic ultraviolet radiation exposure, which has a clear significant effect. Nevertheless, the skin is exposed to many other exposome factors which should be thoroughly considered. Our aim was to assess the impact of exposome factors other than ultraviolet radiation (UVR) on the etiopathology of AK and Bowen's disease (BD) and progression of AK to SCC and to design tailored prevention strategies. We performed an exhaustive literature search in September 2021 through PubMed on the impact of exposome factors other than UVR on AK, BD and SCC. We conducted several parallel searches combining terms of the following topics: AK, BD, SCC and microbiome, hormones, nutrition, alcohol, tobacco, viral infections, chemical contaminants and air pollution. Notably, skin microbiome studies have shown how Staphylococcus aureus infections are associated with AK and AK-to-SCC progression by the production of chronic inflammation. Nutritional studies have demonstrated how a caloric restriction in fat intake, oral nicotinamide and moderate consumption of wine significantly reduce the number of premalignant keratoses and SCC. Regarding lifestyle factors, both alcohol and smoking are associated with the development of SCC in a dose-dependent manner. Relevant environmental factors are viral infections and chemical contaminants. Human papillomavirus infections induce deregulation of cellular proliferation and are associated with AK, BD and SCC. In addition to outdoor jobs, occupations such as industrial processing and farming also increase the risk of developing keratoses and SCC. The exposome of AK will undoubtedly help the understanding of its etiopathology and possible progression to SCC and will serve as a basis to design tailored prevention strategies.

Skin graft associated with platelet-rich plasma in correcting extensive injuries resulting from the resection of skin cancer chemically induced in rats

Purpose:

To evaluate whether using platelet-rich plasma (PRP) in the graft recipient bed after the resection of a neoplasia can influence its recurrence because this product stimulates angiogenesis, mitogenesis and chemotaxis.

Methods:

A study with 30 rats Wistar (Rattus norvegicus albinus), which were separated into group A (induction of carcinogenesis, PRP in the postoperative period) and group B (induction of carcinogenesis, absence of PRP in the postoperative period), with 15 animals in each. Carcinogenesis was induced on the skin of the animals’ chest by the topical application of 0.5% dimethylbenzantracene (DMBA) diluted in acetone. After surgical resection of the induced neoplasia, PRP was used to stimulate angiogenesis before surgical wound synthesis. Data on the control and experimental groups and macroscopic and microscopic variables were evaluated using analysis of variance and the Tukey’s test (5%).

Results:

It was possible to determine that the use of PRP is good in reconstructive surgeries, but it is contraindicated in patients during tumor resection, as it can cause changes in the surgical bed, in addition to stimulating recurrences and metastases.

Conclusions:

PRP may interact with tumour cells that were in the recipient site of the surgical wound during the resection of a neoplasia, and a local recurrence process can be triggered by applying this product.

Risk factors for actinic keratoses: A systematic review and meta-analysis

Objective

To integrate evidence and assess the risk factors associated with actinic keratosis (AK).

Methods

Unrestricted searches were conducted on five electronic databases, with an end-date parameter of September 2021. We summarized the study characteristics and pooled the results from individual studies by using a random-effects model. The risk of bias was estimated using the Cochrane Risk of Bias Tool, and the quality of evidence was estimated according to the Newcastle-Ottawa Scale.

Results

Sixteen studies were included in final analysis, and we assessed the AK risk among a variety of risk factors. Overall, the male sex (odds ratio (OR): 2.51; 95% confidence interval (CI): 1.94-3.25; P < 0.01), age >45 years (OR = 7.65, 95% CI: 2.95-19.86; P < 0.01), light Fitzpatrick skin phototype (OR = 2.32, 95% CI: 1.74-3.10; P < 0.01), light hair color (OR = 2.17, 95% CI: 1.40-3.36; P < 0.01), light eye color (OR = 1.67, 95% CI: 1.03-2.70; P = 0.04), freckles on face/arms (OR = 1.88, 95% CI: 1.37-2.58; P < 0.01), suffered positive history of other types of non-melanoma skin cancer (OR = 4.46, 95% CI: 2.71-7.33; P < 0.01), sunburns in childhood (OR = 2.33, 95% CI: 1.47-3.70; P < 0.01) and adulthood (OR = 1.50, 95% CI: 1.12-2.00; P < 0.01), severe sunburn (OR = 1.94, 95% CI: 1.62-2.31; P < 0.01), and chronic occupational and/or recreational sun exposure (OR = 3.22, 95% CI: 2.16-4.81; P < 0.01) increased the risk of AK. Moreover, sunscreen use (OR = 0.51, 95% CI: 0.34-0.77; P < 0.01) and history of atopy reduced the risk of AK. Sensitivity analysis yielded consistent results. The included studies showed a high risk of bias.

Conclusion

We confirm several well-known AK risk factors and their quantitative data, and summarized the uncommon risk factors and protective factors. Our results may inform on the design and implementation of AK screening and educational programs.

Line-field confocal optical coherence tomography for actinic keratosis and squamous cell carcinoma: a descriptive study

BACKGROUND

Early and accurate diagnosis of cutaneous squamous cell carcinomas (SCCs) and actinic keratoses (AK) is fundamental to reduce their associated morbidity and to select the correct treatment. Line-field confocal optical coherence tomography (LC-OCT) is a new imaging device that can characterize healthy skin and basal cell carcinoma, but no large studies on keratinocyte cell tumours have yet been published.

AIM

To identify and describe LC-OCT criteria associated with SCC and AK, and to compare LC-OCT findings in these tumours.

METHODS

A retrospective observational multicentre study was conducted. Lesions were imaged with the LC-OCT device before surgery and examined histologically. LC-OCT criteria for AK/SCC were identified and their presence was evaluated in all study lesions. Univariate and multivariate analyses were performed to compare AK and SCCs, and to investigate differences between in situ and invasive tumours.

RESULTS

In total, 158 patients with 50 AK and 108 SCCs (62 in situ and 46 invasive) were included. Cytological and architectural alterations were found in most lesions, and differences were found between AK and SCCs. Although the visualization of the dermoepidermal junction (DEJ) was often hampered by hyperkeratosis and acanthosis, an outlined DEJ without broad strands was observed in almost all AK and almost all in situ SCCs, but in only three invasive SCCs (P < 0.001) when the DEJ was detectable.

CONCLUSION

Our results suggest that LC-OCT can help clinicians in the identification of AK and SCC and their differentiation, providing a real-time and noninvasive examination. Further studies are needed to confirm our data.

A multicenter retrospective analysis of the clinical and pathological characteristics of 1188 cases of actinic keratosis in different ultraviolet radiation intensity areas of China

BACKGROUND

Actinic keratosis (AK) is a precancerous disease, caused by ultraviolet radiation (UV).

OBJECTIVE

To analyze the clinical and pathological characteristics of AK in four areas with different ultraviolet radiation intensities.

METHODS

1188 diagnosed AK patients, from January 2000 to July 2015, in dermatology department of four hospitals were collected. The UV intensity of hospital located cities from high to low is Kunming, Yinchuan, Shenyang and Nanjing. The information comes from medical records, and the pathological types and Keratinocyte Intraepithelial Neoplasia (KIN) grades were checked by two experienced pathologists. All information was conducted a retrospective multicenter research.

RESULTS

The patients were mainly middle-aged and elderly female, which was in direct contrast to the majority of men in European. The age of onset in Kunming group was lower than that in Yinchuan Group (p = 0.013) and Nanjing Group (p < 0.01). The course of disease in Kunming group was significantly shorter than that in Nanjing Group (p < 0.001). The lesions were almost located in the exposed area. The proportion of unexposed areas in Shenyang group was significantly higher than that in other groups (p < 0.001). There were statistical differences in pathological morphological classification among the four groups. These differences were not affected by age and gender. The number of KIN III grade patients in Shenyang group was significantly higher than that in other three groups (p < 0.05).

CONCLUSION

The Asian patients were mainly female. The clinical characteristics of AK are closely related to UV intensity, and environmental pollution, lifestyle, religious beliefs and other factors are also related.

How to Assess the Efficacy of Interventions for Actinic Keratosis? A Review with a Focus on Long-Term Results

Actinic keratoses (AK) are common lesions of the skin caused by cumulative sun exposure. Since AK may progress to invasive cutaneous squamous cell carcinoma (cSCC), guidelines uniformly recommend early and consequent treatment. A variety of interventions are available; however, most randomized controlled trials, meta-analyses, and guidelines focus on outcomes that are usually evaluated 8–12 weeks after the end of treatment. Importantly, these assessments can capture the short-term, transient outcomes, but do not allow any conclusions about long-term results to be drawn and do not reflect the probability of transition towards cSCC. Until now, few studies have assessed the long-term results of interventions for AK. Indeed, finding the most appropriate end-point and adjunct time point for determining the long-term results of interventions for AK remains a challenge. Here, we provide an overview of the different ways of measuring the efficacy of AK treatments, such as using recurrence rates or sustained clearance rates, and discuss methodological aspects. Furthermore, we highlight the importance of evidence from post-marketing surveillance trials for the detection of efficacy values and safety signals. Additionally, we emphasize that a follow-up period of 12 months might not be sufficient to reflect the long-term results and stress the urgent need for a longer follow-up period and regular risk-stratified surveillance.

Guidelines of care for the management of actinic keratosis

BACKGROUND

Actinic keratoses (AK) are rough scaly patches that arise on chronically ultraviolet-exposed skin and can progress to keratinocyte carcinoma.

OBJECTIVE

This analysis examined the literature related to the management of AK to provide evidence-based recommendations for treatment. Grading, histologic classification, natural history, risk of progression, and dermatologic surveillance of AKs are also discussed.

METHODS

A multidisciplinary Work Group conducted a systematic review to address 5 clinical questions on the management of AKs and applied the Grading of Recommendations, Assessment, Development, and Evaluation approach for assessing the certainty of the evidence and formulating and grading clinical recommendations. Graded recommendations were voted on to achieve consensus.

RESULTS

Analysis of the evidence resulted in 18 recommendations.

LIMITATIONS

This analysis is based on the best available evidence at the time it was conducted. The pragmatic decision to limit the literature review to English language randomized trials may have excluded data published in other languages or limited identification of relevant long-term follow-up data.

CONCLUSIONS

Strong recommendations are made for using ultraviolet protection, topical imiquimod, topical 5-fluorouracil, and cryosurgery. Conditional recommendations are made for the use of photodynamic therapy and diclofenac for the treatment of AK, both individually and as part of combination therapy regimens.

Randomized controlled trial of fractionated laser resurfacing on aged skin as prophylaxis against actinic neoplasia

BACKGROUNDThe loss of insulin-like growth factor 1 (IGF-1) expression in senescent dermal fibroblasts during aging is associated with an increased risk of nonmelanoma skin cancer (NMSC). We tested how IGF-1 signaling can influence photocarcinogenesis during chronic UVB exposure to determine if fractionated laser resurfacing (FLR) of aged skin, which upregulates dermal IGF-1 levels, can prevent the occurrence of actinic keratosis (AK) and NMSC.METHODSA human skin/immunodeficient mouse xenografting model was used to test the effects of a small molecule inhibitor of the IGF-1 receptor on chronic UVB radiation. Subsequently, the durability of FLR treatment was tested on a cohort of human participants aged 65 years and older. Finally, 48 individuals aged 60 years and older with considerable actinic damage were enrolled in a prospective randomized clinical trial in which they underwent a single unilateral FLR treatment of one lower arm. Numbers of AKs/NMSCs were recorded on both extremities for up to 36 months in blinded fashion.RESULTSXenografting studies revealed that chronic UVB treatment with a topical IGF-1R inhibitor resulted in a procarcinogenic response. A single FLR treatment was durable in restoring appropriate UVB response in geriatric skin for at least 2 years. FLR resulted in sustained reduction in numbers of AKs and decreased numbers of NMSCs in the treated arm (2 NMSCs) versus the untreated arm (24 NMSCs).CONCLUSIONThe elimination of senescent fibroblasts via FLR reduced the procarcinogenic UVB response of aged skin. Thus, wounding therapies are a potentially effective prophylaxis for managing high-risk populations.TRIAL REGISTRATIONClinicalTrials.gov (NCT03906253).FUNDINGNational Institutes of Health, Veterans Administration.

Protective effects of sunscreen (50+) and octatrienoic acid 0.1% in actinic keratosis and UV damages

Actinic keratosis is a form of dysplastic epidermal lesion resulting from chronic and excessive UV exposure with a certain risk of becoming cancerous. Current guidelines advocated the use of sunscreens to prevent photodamage. An efficient photoprotection must involve both primary protective factors such as UV filters and secondary factors (eg, antioxidants) able to disrupt the photochemical and genetic cascade triggered by UVs. An in vitro model of human skin (Phenion FT) was used to assess the photoprotective potential of a sunscreen containing inorganic sun-filters (50+ SPF) and 0.1% octatrienoic acid (KERA’+) after UVA (10 J/cm²) and UVB (25 mJ/cm²) by means of evaluation of the number of sunburn cells (SBCs) and apoptotic keratinocytes. Also resulting alterations in the gene expression of markers involved in apoptosis (Tumor protein 53), inflammation/immunosuppression (IL-6 and IL-8), oxidative stress (oxidative stress response enzyme heme oxygenase 1), remodeling (metalloproteinase 1) and cell-cell adhesion (E-cadherin) were investigated. Gene expression was investigated using quantitative real-time PCR. This work demonstrated that the sunscreen preparations under study (with and without 0.1% octatrienoic acid, respectively) can be distinguished about their ability to prevent UVs-induced damage. Synergism between the inorganic filters and 0.1% octatrienoic acid was found (KERA’+) on all end points analyzed and this effect was found to be statistically significant (p<0.05). Our data revealed that topical application of a sunscreen containing inorganic filters (50+SPF) and 0.1% octatrienoic acid can protect from SBC formation, reduce the number of apoptotic keratinocytes and protect from the main molecular alterations caused by UV radiations.

Evaluation of Long-term Clearance Rates of Interventions for Actinic Keratosis: A Systematic Review and Network Meta-analysis

Importance

Multiple interventions are available for the treatment of actinic keratosis (AK). However, most randomized clinical trials and meta-analyses focus on short-term efficacy outcomes.

Objective

To investigate and synthesize the long-term efficacy (≥12 months) of interventions for AK from parallel-arm randomized clinical trials.

Data Sources

Searches in MEDLINE, Embase, and Central were conducted from inception until April 6, 2020. The reference lists of the included studies and pertinent trial registers were hand searched. The study was completed February 27, 2021.

Study Selection

Two reviewers screened the titles and abstracts of 2741 records. Finally, 17 published reports (original studies and follow-up reports) referring to 15 independent randomized clinical trials with an overall sample size of 4252 patients were included.

Data Extraction and Synthesis

Two reviewers independently extracted data on study, patient, and intervention characteristics. Network meta-analysis (NMA) of each outcome was conducted with a frequentist approach. The Grading of Recommendations Assessment, Development, and Evaluation (GRADE) guidance for NMA was used to assess the certainty of evidence. The revised Cochrane risk-of-bias tool for randomized clinical trials was used to evaluate the methodologic quality.

Main Outcomes and Measures

Participant complete clearance, participant partial clearance, and lesion-specific clearance were the outcomes, with each assessed at least 12 months after the end of treatment.

Results

Data from 15 independent randomized clinical trials including 4252 patients were extracted and synthesized. Ten studies were included in an NMA for the outcome of participant complete clearance, with photodynamic therapy with aminolevulinate (ALA-PDT) showing the most favorable risk ratio (RR) compared with placebo (RR, 8.06; 95% CI, 2.07-31.37; GRADE, moderate), followed by imiquimod, 5% (RR, 5.98; 95% CI, 2.26-15.84; GRADE, very low), photodynamic therapy with methyl aminolevulinate (MAL-PDT) (RR, 5.95; 95% CI, 1.21-29.41; GRADE, low), and cryosurgery (RR, 4.67; 95% CI, 1.36-16.66; GRADE, very low). Similarly, ALA-PDT had the highest RR in the NMA for lesion-specific clearance (RR, 5.08; 95% CI, 2.49-10.33; GRADE, moderate). No NMA was possible for participant partial clearance owing to poor reporting of this outcome.

Conclusions and Relevance

This systematic review and network meta-analysis found that therapy including ALA-PDT, imiquimod, 5%, MAL-PDT, and cryosurgery was associated with significant long-term efficacy in the NMA. This study provides data for a possible use in an evidence-based framework for selecting interventions with sustained lesion clearance.

Successful treatment of early cutaneous squamous cell carcinoma with hypofractionated radiation therapy in an African lion (Panthera leo)

Cutaneous squamous cell carcinoma (SCC) is a slow growing but locally invasive neoplasm, most commonly caused by prolonged exposure to ultraviolet (UV) radiation. Whilst SCC accounts for 15% of skin tumours in domesticated cats, cutaneous SCC in non-domesticated felids (apart from captive snow leopards) appears to be uncommon, with only three reports in the literature to date. In this report, a captive African lion (Panthera leo) presented with two ulcerative lesions on the nasal planum. Histopathology of the lesions revealed epidermal keratinocyte dysplasia and neoplastic basal- and supra-basal epithelial cells with dyskeratosis and evidence of basement membrane breaching and dermal invasion, consistent with a diagnosis of SCC. There was also evidence of laminar fibrosis and inflammation of the subjacent dermis suggesting that the SCC most likely resulted from UV-induced neoplastic transformation of the epidermal squamous epithelium following actinic keratosis. The lion was treated with hypofractionated radiation therapy and remained in remission until his death (euthanised 17 months later because of age-related chronic renal failure). This is the first report of cutaneous SCC in a lion with evidence of actinic damage and resolution after radiation therapy.

In-Vivo LC-OCT Evaluation of the Downward Proliferation Pattern of Keratinocytes in Actinic Keratosis in Comparison with Histology: First Impressions from a Pilot Study

It is known that actinic keratoses (AKs) can progress to invasive squamous cell carcinoma (SCC). The histological PRO grading of AKs is based on the growth pattern of basal keratinocytes and relates to their progression risk. AKs can be non-invasively characterized by line-field confocal optical coherence tomography (LC-OCT). The aim of the study was to define criteria for an LC-OCT grading of AKs based on the PRO classification and to correlate it with its histological counterpart. To evaluate the interobserver agreement for the LC-OCT PRO classification, fifty AKs were imaged by LC-OCT and biopsied for histopathology. PRO histological grading was assessed by an expert consensus, while two evaluator groups separately performed LC-OCT grading on vertical sections. The agreement between LC-OCT and histological PRO grading was 75% for all lesions (weighted kappa 0.66, 95% CI 0.48-0.83, p ≤ 0.001) and 85.4% when comparing the subgroups PRO I vs. PRO II/III (weighted kappa 0.64, 95% CI 0.40-0.88, p ≤ 0.001). The interobserver agreement for LC-OCT was 90% (Cohen's kappa 0.84, 95% CI 0.71-0.91, p ≤ 0.001). In this pilot study, we demonstrated that LC-OCT is potentially able to classify AKs based on the basal growth pattern of keratinocytes, in-vivo reproducing the PRO classification, with strong interobserver agreement and a good correlation with histopathology.

Modeling transcriptomic age using knowledge-primed artificial neural networks

The development of 'age clocks', machine learning models predicting age from biological data, has been a major milestone in the search for reliable markers of biological age and has since become an invaluable tool in aging research. However, beyond their unquestionable utility, current clocks offer little insight into the molecular biological processes driving aging, and their inner workings often remain non-transparent. Here we propose a new type of age clock, one that couples predictivity with interpretability of the underlying biology, achieved through the incorporation of prior knowledge into the model design. The clock, an artificial neural network constructed according to well-described biological pathways, allows the prediction of age from gene expression data of skin tissue with high accuracy, while at the same time capturing and revealing aging states of the pathways driving the prediction. The model recapitulates known associations of aging gene knockdowns in simulation experiments and demonstrates its utility in deciphering the main pathways by which accelerated aging conditions such as Hutchinson-Gilford progeria syndrome, as well as pro-longevity interventions like caloric restriction, exert their effects.

Follicular extension of atypical keratinocytes predicts the resistance of actinic keratosis to topical imiquimod treatment: A single-center retrospective analysis

Topical imiquimod therapy has been widely used for actinic keratosis (AK). However, some cases are refractory to treatment. Therefore, an indicator that can predict its efficacy is desired. Herein, we retrospectively analyzed 52 AK lesions treated with imiquimod to investigate the characteristics of refractory lesions. Imiquimod was applied in a cycle of three times weekly for 4 weeks, followed by a 4-week break. This treatment cycle was repeated up to three times and treatment responses were evaluated. As a result, a complete response (CR) was observed in 78.8% (41/52) of lesions. Next, treatment response of lesions was correlated with clinicopathological characteristics including clinical morphology and thickness, pathological morphology and thickness, and presence of follicular extension (FE). Of these, lesions with FE were significantly less responsive to imiquimod treatment; while 92.6% of AK lesions without FE achieved a CR, only 64.0% of AK lesions with FE achieved a CR (p = 0.029). Logistic regression analysis revealed that FE was the sole significant predictor of its efficacy (p = 0.019). These results suggest that preliminary histological evaluation of FE may be useful to predict the efficacy of imiquimod for AK.

Actinic keratoses contiguous with squamous cell carcinomas are mostly non-hyperkeratotic and with severe dysplasia

AIMS

Actinic keratosis (AK) is a precursor of cutaneous squamous cell carcinoma (SCC). No validated parameters can predict which AKs will progress into SCCs, but especially thick AKs are under suspicion. The clinical and histopathological thickness of AKs is strongly correlated. This study aimed to investigate the thicknesses and degree of dysplasia of AKs contiguous with SCCs assuming these AKs represent the AKs that have undergone malignant transformation.

METHODS

Files of the Pathology Department, Hospital of Southern Jutland, Denmark, were reviewed. 111 cases met the inclusion criteria: a skin biopsy containing an invasive SCC. All SCCs merged with an AK at the edge. Degree of dysplasia, epidermal thickness and stratum corneum thicknesses of AKs were measured.

RESULTS

All AKs showed severe dysplasia. Most AKs had a stratum corneum thickness under 0.1 mm and an epidermal thickness under 0.5 mm, corresponding to clinically thin and non-hyperkeratotic AKs.

CONCLUSIONS

Our result suggests malignant progression potential of AKs regardless of thickness.

Expression Profile of Fibroblast Growth Factor Receptors, Keratinocyte Differentiation Markers, and Epithelial Mesenchymal Transition-Related Genes in Actinic Keratosis: A Possible Predictive Factor for Malignant Progression?

Simple Summary

In this work, we checked the modulation of Fibroblast Growth Factor Receptors (FGFRs) along with differentiation-related and epithelial-to-mesenchymal transition (EMT)-related markers to identify expression profiles that could be predictive for actinic keratosis (AK) progression through the “differentiated” pathway. We found that the downregulation of the analyzed differentiation markers, but not the modulation of the EMT-related markers, correlated with the canonical progression of AK. In addition, the observed modulation of FGFR2 mesenchymal/epithelial isoforms compatible with FGFR2 isoform switch, as well as the upregulation of FGFR4 suggested their correlation with early steps of AK pathogenesis. In contrast, the increase of mesenchymal FGFR3c isoform expression appeared to suggest that this event correlated with late steps of AK progression. In addition, the strong modulation of filaggrin (FIL), Snail1, as well as of FGFR2c, FGFR4, and their ligand Fibroblast Growth Factor 2 (FGF2), observed in some of the keratinocytic intraepithelial neoplasia grade I (KIN I) samples, may indicate that they could be molecular markers predictive for those KIN I lesions destined to a direct progression to squamous cell carcinoma (SCC) through the “differentiated” pathway.

Abstract

Actinic keratosis (AK) is the ultra violet (UV)-induced preneoplastic skin lesion clinically classified in low (KIN I), intermediate (KIN II), and high (KIN III) grade lesions. In this work we analyzed the expression of Fibroblast Growth Factor Receptors (FGFRs), as well as of keratinocyte differentiation and epithelial-to-mesenchymal transition (EMT)-related markers in differentially graded AK lesions, in order to identify specific expression profiles that could be predictive for direct progression of some KIN I lesions towards squamous cell carcinoma (SCC). Our molecular analysis showed that the keratinocyte differentiation markers keratin 1 (K1), desmoglein-1 (DSG1), and filaggrin (FIL) were progressively downregulated in KIN I, II, and III lesions, while the modulation of epithelial/mesenchymal markers and the induction of the transcription factors Snail1 and Zinc finger E-box-binding homeobox 1 (ZEB1) compatible with pathological EMT, even if observable, did not appear to correlate with AK progression. Concerning FGFRs, a modulation of epithelial isoform of FGFR2 (FGFR2b) and the mesenchymal FGFR2c isoform compatible with an FGFR2 isoform switch, as well as FGFR4 upregulation were observed starting from KIN I lesions, suggesting that they could be events involved in early steps of AK pathogenesis. In contrast, the increase of FGFR3c expression, mainly appreciable in KIN II and KIN III lesions, suggested a correlation with AK late progression. Interestingly, the strong modulation of FIL, Snail1, as well as of FGFR2c, FGFR4, and of their ligand FGF2, observed in some of the KIN I samples, may indicate that they could be molecular markers predictive for those low graded lesions destined to a direct progression to SCC. In conclusion, our data point on the identification of molecular markers predictive for AK rapid progression through the “differentiated” pathway. Our results also represent an important step that, in future, will help to clarify the molecular mechanisms underlying FGFR signaling deregulation in epithelial tissues during the switch from the pre-neoplastic to the oncogenic malignant phenotype.

In vivo reflectance confocal microscopy for monitoring actinic keratosis treated with 5-aminolevulinic acid photodynamic therapy

BACKGROUND

Actinic keratosis (AK) occurs frequently in sun-exposed skin while its diagnosis and treatment were still in exploration.

MATERIALS AND METHODS

Thirty two patients with facial AK lesions were selected and examined with reflective confocal microscopy (RCM) firstly, followed by biopsy at the same site. RCM was used to observe AK lesions before 5-aminolevulinic acid photodynamic therapy (ALA-PDT) treatment, after the first treatment, after 4 treatments, and at 1 and 6 months follow-up. Retrospective analysis of RCM images was performed.

RESULTS

Thirty two AK cases showed initial RCM microscopic features including disorderly arranged epidermal cells (100%), atypical keratinocytes (100%), and blurry border between the epidermis and dermis (100%). 4 patients quitted trail. After treatments, 24 cases showed basically regular arrangement of epidermal cells, absent atypical keratinocytes, and clear border between epidermis and dermis, while 4 cases improved little. At 1 and 6 months follow-up, 23 cases remained relapse-free while 1 case developed recurrent symptoms. Effective rate of 4 ALA-PDT treatments for AK was 100%; recurrence and cure rates were 4.2% and 82.1%, respectively.

CONCLUSION

ALA-PDT is effective to treat AK, while RCM can be recommended for in vivo evaluating and monitoring the effect of ALA-PDT on AK.

[Decision criteria and patient characteristics for patient-oriented treatment of field cancerization : Standardized algorithm for personalized treatment concepts]

Hintergrund

Aktinische Keratosen (AK) zeichnen sich durch einen chronischen Verlauf aus, und häufig ist ein ganzes Hautareal betroffen (Feldkanzerisierung). Die patientenindividuelle Abwägung therapiespezifischer Vor- und Nachteile einer feldgerichteten Therapie ist herausfordernd.

Fragestellung

Ziel der vorliegenden Arbeit war die Entwicklung und Evaluierung patientenorientierter Entscheidungskriterien, die sich für die pragmatische Einordnung einer AK-Feldtherapie im Behandlungsalltag bei Patienten mit besonderer Prädisposition zur Feldkanzerisierung eignen (Patiententyp 1 bis 3).

Material und Methoden

Die Entwicklung der Entscheidungskriterien und der Patiententypologie erfolgte im Rahmen eines nominalen bzw. strukturierten Multi-level-Gruppenprozesses. Anhand der patientenrelevanten Entscheidungskriterien, der verfügbaren Evidenz aus klinischen Studien und entlang der Patiententypologie wurde ein Bewertungsalgorithmus etabliert, und feldgerichtete AK-Therapieoptionen wurden systematisch evaluiert.

Ergebnisse

Als patientenrelevante Kriterien für die Therapieentscheidung wurden u. a. Effektivität, Sicherheit, Praktikabilität der Therapie, Adhärenz, Kosmetik, Patientenpräferenz und Komorbiditäten identifiziert und näher spezifiziert. In Bezug auf diese Entscheidungskriterien und Patiententypen, bei denen eine Feldtherapie vorrangig indiziert ist, erfüllte die photodynamische Therapie mit Tageslicht das therapiebezogene Anforderungsprofil in besonderem Maße.

Schlussfolgerung

Die Definition von patientenrelevanten und therapiebezogenen Entscheidungskriterien in der AK-Feldtherapie erlaubt eine strukturierte und gleichzeitig praxisorientierte Herangehensweise, um spezifische Therapieoptionen einzuordnen und individuelle Therapieentscheidungen herzuleiten.

Effectiveness and tolerability of treatment for isolated actinic keratoses: A retrospective comparison between cryotherapy, CO2 laser and 5-fluorouracil 0.5%/salicylic acid 10

Actinic keratoses (AK) have been described as either intraepithelial keratinocytic dysplasia that can evolve into invasive squamous cell carcinoma (SCC) or as in situ SCC that can progress into an invasive form. A retrospective study was conducted to compare outcomes of three different topical therapies for patients with single AK (<4): cryotherapy, CO₂ laser and 5-fluorouracil 0.5%/salicylic acid 10%. We included 72 patients who presented at the Dermatology Clinic of Maggiore Hospital of Trieste between 1 November 2019 and 31 January 2020 for the treatment of AKs. All treatments led to a significant reduction in the average diameter of AK. Pain felt by patients was significantly lower after 5-FU 0.5%/SA 10%. Side effects appeared similarly distributed among the three groups, with erythema and crusts being the most frequent. Aesthetic outcomes were highest in the 5-FU 5%/SA 10% group, as evaluated by both the patient and the operator. Cryotherapy, CO₂ laser and 5-FU 5%/SA 10% were all effective, with no significant efficacy differences among them. Additionally, 5-FU 5%/SA 10% was proved to have the best aesthetic result and to cause the least pain, while necessitating long-term administration. This should be taken into account for patients with low pain tolerance and low treatment adherence. Cryotherapy and CO₂ laser have the advantage of requiring a single session, which might be more suitable for uncooperative patients.

Presence of intralesional melanocytes as a histopathological feature of actinic keratosis based on in vivo harmonic generation microscopy in Asians

BACKGROUND

Most patients with actinic keratosis (AK) present with more than one lesion. Although histopathological examination is the gold standard for diagnosing this condition, performing an invasive skin biopsy for each AK is impractical. Thus, this study aimed to identify AK's morphological characteristics based on harmonic generation microscopy (HGM). Moreover, the correlation between features observed using HGM and histopathological grading of AK was examined.

METHODS

Lesions of seven patients were examined using HGM (n = 1, ex vivo and n = 6, in vivo), and histopathological examinations of the biopsy specimens were also performed. The features of each AK, based on HGM, were assessed and compared with corresponding standard histopathological findings.

RESULTS

Using the histopathological findings as a standard reference, HGM's accuracy in detecting features of AK lesions, such as hyperkeratosis, epidermal thinning, abnormal architecture, and atypical honeycomb pattern, was 100%. Approximately five (72%) patients had similar histopathological grades. Moreover, based on HGM, except for one patient with grade 1 AK, six (85.71%) patients had lesions with intraepidermal dendritic cell-like cells, representing melanocytes.

CONCLUSION

Harmonic generation microscopy can be used in vivo to provide critical diagnostic information with a resolution comparable to histopathological examination. In addition, intralesional melanocytes in AK, which may be correlated with disease severity, can be specifically enhanced using HGM.

Invasive squamous cell carcinomas and precursor lesions on UV-exposed epithelia demonstrate concordant genomic complexity in driver genes

Although squamous cell carcinomas (SCC) are the most frequent human solid tumor at many anatomic sites, the driving molecular alterations underlying their progression from precursor lesions are poorly understood, especially in the context of photodamage. Therefore, we used high-depth, targeted next-generation sequencing (NGS) of RNA and DNA from routine tissue samples to characterize the progression of both well- (cutaneous) and poorly (ocular) studied SCCs. We assessed 56 formalin-fixed paraffin-embedded (FFPE) cutaneous lesions (n = 8 actinic keratosis, n = 30 carcinoma in situ [CIS], n = 18 invasive) and 43 FFPE ocular surface lesions (n = 2 conjunctival/corneal intraepithelial neoplasia, n = 20 CIS, n = 21 invasive), from institutions in the US and Brazil. An additional seven cases of advanced cutaneous SCC were profiled by hybrid capture-based NGS of >1500 genes. The cutaneous and ocular squamous neoplasms displayed a predominance of UV-signature mutations. Precursor lesions had highly similar somatic genomic landscapes to SCCs, including chromosomal gains of 3q involving SOX2, and highly recurrent mutations and/or loss of heterozygosity events affecting tumor suppressors TP53 and CDKN2A. Additionally, we identify a novel molecular subclass of CIS with RB1 mutations. Among TP53 wild-type tumors, human papillomavirus transcript was detected in one matched pair of cutaneous CIS and SCC. Amplicon-based whole-transcriptome sequencing of select 20 cutaneous lesions demonstrated significant upregulation of pro-invasion genes in cutaneous SCCs relative to precursors, including MMP1, MMP3, MMP9, LAMC2, LGALS1, and TNFRSF12A. Together, ocular and cutaneous squamous neoplasms demonstrate similar alterations, supporting a common model for neoplasia in UV-exposed epithelia. Treatment modalities useful for cutaneous SCC may also be effective in ocular SCC given the genetic similarity between these tumor types. Importantly, in both systems, precursor lesions possess the full complement of major genetic changes seen in SCC, supporting non-genetic drivers of invasiveness.