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.

Application of microneedling in photodynamic therapy: A systematic review.

BACKGROUND: The application of photodynamic therapy (PDT) is pivotal in the management of diverse dermatologic conditions. Microneedling (MN) is a minimally invasive tool that is capable of inducing transient pores on the skin to facilitate transdermal drug delivery. Several studies have reported augmentation of PDT combined with MN. This systematic review analyzes the current studies on the efficacy and safety of MN-assisted PDT for skin diseases. METHODS: The literature search using the PRISMA standard was completed through PubMed, Embase, Web of Science and CENTRAL from the establishment of the databases to November 2023. Two independent researchers finished the procedure. RESULTS: A total of 12 articles and 413 subjects met our study criteria. This systematic review suggests that MN-assisted PDT can decrease the incubation time required for the photosensitizer and reduce skin lesions of actinic keratosis (AK) . The common side effect is pain and no serious adverse events were reported. CONCLUSIONS: MN is an effective method to increase the transdermal delivery rate of photosensitizers. For different photosensitizers and disease, MN may show different clinical effects.

Field Cancerization Therapies for the Management of Actinic Keratosis: An Updated Review.

Field cancerization theory highlights that the skin surrounding actinic keratoses (AK) is also at increased risk for possible malignant transformation; thus, field-directed treatments may both reduce the risk of AK recurrence and potentially reduce the risk of development of cutaneous squamous cell carcinoma (cSCC). Photodynamic therapy (PDT) with either aminolevulinic acid (ALA) or methylaminolevulinate (MAL), as well as topical treatments such as 5-fluorouracil (5-FU), diclofenac gel, piroxicam, imiquimod, and ingenol mebutate, have all shown higher efficacy than vehicle treatments. PDT is widely recognized for its high efficacy; however, concerns for associated pain have driven new studies to begin using alternative illumination and pretreatment techniques, including lasers. Among topical treatments, a combination of 5-FU and salicylic acid (5-FU-SA) has shown to be the most effective but also causes the most adverse reactions. Tirbanibulin, a new topical agent approved for use in 2020, boasts a favorable safety profile in comparison with imiquimod, 5-FU, and diclofenac. Meanwhile, ingenol mebutate is no longer recommended for the treatment of AKs due to concerns for increased risk of cSCC development. Moving forward, an increasing number of studies push for standardization of outcome measures to better predict risk of future cSCC and use of more effective measures of cost to better guide patients. Here, we present an updated and comprehensive narrative review both confirming the efficacy of previously mentioned therapies as well as highlighting new approaches to PDT and discussing the use of lasers and novel topical treatments for treatment of AK.

Shedding new light on actinic keratoses and squamous cell carcinoma in situ.

ABSTRACT: Cutaneous squamous cell carcinoma can arise from various premalignant lesions such as actinic keratosis, Bowen disease, and premalignant genital squamous cell lesions. Identification and treatment can prevent malignant transformation and death. This article describes the causes, epidemiology, and characteristics of suspicious premalignant squamous cell lesions so that clinicians can identify these lesions and refer patients for specialist treatment as appropriate.

Needs and challenges among general practitioners in the management of actinic keratosis: a qualitative study.

BACKGROUND: Because of the increasing incidence of actinic keratosis (AK), optimal use of limited healthcare resources is essential. Although most patients can be managed in primary care, dermatology referrals are common. More profound knowledge of general practitioners' (GPs) considerations might assist in enhancing AK care. METHODS: The aim of the current study was to gain insight into AK management in primary care by exploring the needs and challenges among GPs in the Netherlands. A qualitative study was conducted based on semi-structured in-depth interviews with 15 conveniently sampled Dutch GPs, focusing on the needs and challenges in AK management. A literature-informed, predefined topic list guided the interviews, which were recorded, transcribed ad verbatim, and thematically analysed using the Framework Method. RESULTS: All GPs reported AK to be a clinical diagnosis and most GPs indicated that most AK patients could be managed in primary care. Cryotherapy was preferred and experience with 5-FU therapy was limited. Most GPs applied cryotherapy without discussing other treatment options with patients. Reasons for dermatology referrals included an incomplete treatment response, extensive lesions, difficult-to-treat areas, and serious doubts about the diagnosis. GPs reported a need for more education, especially on 5-FU therapy. Their main challenges were dealing with diagnostic uncertainty, treating extensive lesions, managing treatment-related skin reactions, and reconciling patient misconceptions. CONCLUSIONS: This study shows various AK management approaches among Dutch GPs with suboptimal guideline compliance due to diverse underlying barriers. It suggests that more education might contribute to a more standardised and uniform AK management and supports further transition of AK care from hospital to primary care.

Folliculotropism in Actinic Keratoses in Patients not Responding to Treatments: A Pilot Study.

Dear Editor, Actinic keratoses (AK) have a high prevalence in the general population, with greater rates in Caucasian patients after the fourth and fifth decades of life (37.5-60.0%) (1,2). Standard histopathologic reporting of AKs does not provide information on the presence of atypical keratinocytes extending to the hair follicle, also defined as folliculotropism (FLC). Commonly, atypical cells in AKs do not present FLC, but this feature can be observed in bowenoid AKs with full-thickness epidermal atypia (3,4). FLC has been considered a possible element enhancing the chances of a progression toward invasive SCC (iSCC). Fernandez-Figueras et al. (3) reported that the depth of FLC in AKs was correlated with the invasiveness of associated iSCC. Pandey et al. (5) reported a positive association between AKs with FLC and history of invasive cutaneous cancer or melanoma, more often in men at an older age. The role of FLC in cutaneous melanoma is still debated, but it is considered a parameter that may correlate with treatment response in lentigo maligna and disease progression or recurrences in invasive tumors (6,7). These studies draw particular attention to the potential role of hair bulge compartment stem cells in favoring tumor progression through the expression of adhesion molecules, cytokines, and growth factor receptors (8). Aks are known to have a high recurrence rate after topical treatment (1). The risk of evolution to an iSCC is not completely clear, but it has been estimated to be around 0.6% at 12 months and up to 2.5% at 48 months (1,3,7). Considering the possible progression and the heavy burden of AK treatments, including the economic burden, it is imperative to focus on histopathologic features associated with treatment failure. The aim of this preliminary study was to assess the histopathologic features, specifically FLC, of AK samples from patients considered "non-responders" to specific topical treatments. A secondary endpoint was to assess the clinical/dermoscopic features. Patients were considered "non-responders" if the lesions persisted after two alternated completed cycles of treatments with ingenol mebutate, imiquimod, diclofenac 3%, or 5-fluoruracil. Patients with a positive history of immunosuppression or genetic diseases were excluded. The study was approved by the local Ethics Committee. Slides of AKs diagnosed at the Laboratory of Dermatopathology, University of Bologna, Italy from January 2016 to October 2018 were reviewed by two dermatopathologists (CM, PAF). 155 "non-responder" AKs of five main histopathologic subtypes were included, classified from grade I to III according to the Roewert-Huber classification (9) (Table 1). The proliferative and atrophic histopathologic subtypes of AKs were detected in 33.6% and 30.4% samples, respectively. FLC was observed in 75.3% of the cases, subdivided into two categories, periadnexal (48.9%) and intraadnexal (26.4%). Periadnexal FLC was detected in 31.0% of atrophic and in 50.3% of proliferative AKs, while intraadnexal FLC was found in 48.7% and 29.2%, respectively (Figure 1, a, b). At dermoscopy, most lesions had been classified as grade I or II (38.8% and 45.8%), and only 15.4% as grade III, showing an unexpected non-response to treatment according to the dermoscopic criteria. In contrast, almost half of the AKs were classified as grade III at histology, revealing a discrepancy between the dermoscopic grading and histological findings in a majority of cases (77.4%) (Figure 2, c, d). Furthermore, atrophic and proliferative AKs accounted for 64.0% of total cases, and these are the variants associated with a higher probability of evolution toward an iSCC (10). The clinical/histological discrepancy has already been reported in the literature (9) and may represent a misleading factor for treatment choice and outcomes. We believe that a comparative analysis with dermoscopy and histology should be performed in non-responding AKs, in order to choose the best therapeutic option. In fact, some superficial treatments (such as cryotherapy) may not provide a good response in deep hair follicles (4). We also suggest encouraging greater focus on FLC and its description in pathology reports. This is a preliminary observational study, but it reinforces the need to further larger clinical studies investigating the role of specific histopathologic parameters in AKs, including FLC, that may correlate with treatment outcomes.

[Treatment of actinic keratoses in older adults]. / Therapie aktinischer Keratosen beim älteren Menschen.

Actinic keratoses (AKs) are common precancerous skin lesions that primarily affect older adults due to cumulative sun exposure. Given the increased vulnerability of older adults to developing AKs, appropriate therapeutic strategies are crucial to prevent their progression to invasive squamous cell carcinoma. This comprehensive review aims to explore the various treatment modalities available for AKs in the elderly population, focusing on their efficacy, safety, and suitability for this specific age group. The article discusses topical treatments, cryotherapy, photodynamic therapy, chemical peels, and surgical interventions, providing a detailed analysis of their mechanisms of action, benefits, limitations, and considerations in geriatric patients. Furthermore, the importance of individualized treatment plans, considering factors such as comorbidities, medication interactions, and patient preferences, are highlighted.

Ablative Fractional Laser Enhances Artificial or Natural Daylight Photodynamic Therapy of Actinic Field Cancerization: A Randomized and Investigator-initiated Half-side Comparative Study.

Artificial daylight photodynamic therapy is a near-painless treatment for actinic keratoses, which can be performed indoors using a controlled light dose. Daylight photodynamic therapy is approved only for treatment of grade I-II actinic keratoses. The aim of this study was to evaluate whether fractional laser pre-treatment improves the outcomes of daylight photodynamic therapy for actinic keratoses of all grades. In addition, the study compared the outcomes of artificial and natural daylight photodynamic therapy. This randomized single-blinded split-side comparative study included 60 patients with ≥ 2 actinic keratoses of the head. Fractional laser pre-treatment was assigned randomly for actinic keratoses on 1 side of the head and, subsequently, the entire treatment area was treated with artificial or natural daylight photodynamic therapy. Fractional laser-mediated daylight photodynamic therapy achieved significantly higher complete clearance (50.0% vs 30.3%, p = 0.04), partial clearance (78.6% vs 50.0%, p < 0.01) and lesion-specific clearance (86.2% vs 70.2%, p < 0.01) than daylight photodynamic therapy alone at the 6-month follow-up. No significant differences were found in the outcomes of artificial vs natural daylight photodynamic therapy or grade I lesions vs grade II-III lesions. Thus, fractional laser pre-treatment appears to significantly increase the efficacy of artificial and natural daylight photodynamic therapy, and to be suitable for treatment of actinic keratoses of all grades.

Expert Recommendations on Facilitating Personalized Approaches to Long-term Management of Actinic Keratosis: The Personalizing Actinic Keratosis Treatment (PAKT) Project.

Actinic keratoses are pre-malignant skin lesions that require personalized care, a lack of which may result in poor treatment adherence and suboptimal outcomes. Current guidance on personalizing care is limited, notably in terms of tailoring treatment to individual patient priorities and goals and supporting shared decision-making between healthcare professionals and patients. The aim of the Personalizing Actinic Keratosis Treatment panel, comprised of 12 dermatologists, was to identify current unmet needs in care and, using a modified Delphi approach, develop recommendations to support personalized, long-term management of actinic keratoses lesions. Panellists generated recommendations by voting on consensus statements. Voting was blinded and consensus was defined as ≥ 75% voting 'agree' or 'strongly agree'. Statements that reached consensus were used to develop a clinical tool, of which, the goal was to improve understanding of disease chronicity, and the need for long-term, repeated treatment cycles. The tool highlights key decision stages across the patient journey and captures the panellist's ratings of treatment options for attributes prioritized by patients. The expert recommendations and the clinical tool can be used to facilitate patient-centric management of actinic keratoses in daily practice, encompassing patient priorities and goals to set realistic treatment expectations and improve care outcomes.

Actinic keratosis - lesions behind the mask.

INTRODUCTION: Actinic keratoses (AKs) are common skin lesions that arise in skin areas chronically exposed to ultraviolet (UV) radiation. They may progress to squamous cell carcinomas in 16% of cases within 1 year. Clinically, they present as erythematous scaly plaques and mainly affect face, neck, chest, back of the hands, shoulders and scalp. Cumulative exposure to UV radiation is the main risk factor. Other factors are advanced age, outdoor activities, geographic characteristics, exposure to artificial UV radiation and chronic skin inflammation. Many of these factors are often present in rural populations where agriculture remains important. METHODS/RESULTS: This presentation present the case of a 67-year-old male patient, who went to his Family Doctor for odynophagia with 2 days of evolution. He had hypertrophied and erythematous tonsils with purulent exudate and was medicated with amoxicillin-clavulanic acid 875+125 mg for 8 days with improvement of symptoms. To perform the observation of the oropharynx, he was asked to remove his face mask, which revealed an erythematous scaly lesion in the left malar region, suggestive of actinic keratosis. He was referred to Dermatology where cryotherapy of the lesion was performed with a favourable evolution without relapses. DISCUSSION: AKs are pre-malignant lesions. Rural populations are particularly at risk for their development. It is therefore essential to raise awareness for the use of protective measures as well as to investigate lesions already established. This case seeks to alert for the fact that the use of masks due to COVID-19 pandemic can hide pre-malignant lesions of the face with a consequent delay in diagnosis and treatment.

Classifying Actinic Keratosis: What the Reality of Everyday Clinical Practice Shows Us.

Difficulties faced by clinicians in routine clinical practice when selecting the appropriate treatment for patients with actinic keratosis (AK) include: the independent evaluation of AK lesions, the absence of a standardized definition of field cancerization (FC), and the lack of a reproducible classification to grade the entire AK-affected area. Moreover, to assess the severity of AK, most guidelines rely on lesion count, which is often not reproducible among specialists. The present work has 2 main objectives: first, to review and highlight some of the issues clinicians tackle when classifying and monitoring AK lesions and the status of FC, looking in more detail at some of the most commonly used clinical scales for classifying AK lesions. Second, we pose questions that we encounter in daily clinical practice, and whose answers or comments help to deal with cases of AK, facilitating the work of clinicians: How should we approach AK diagnosis? How do the challenges of clinical studies on the evaluation of treatment efficacy translate into clinical practice? We review the literature on the clinical classifications and management of AK, and propose how to guide the diagnosis, management, and monitoring of patients with AK. J Drugs Dermatol. 2022;21(8):845-849. doi:10.36849/JDD.6704.

Actinic Keratoses (AK): An Exploratory Questionnaire-Based Study of Patients' Illness Perceptions.

BACKGROUND: Decreased illness perception among actinic keratoses (AK) patients is a major barrier to the effective management of AK. OBJECTIVE: We aimed to investigate patients' illness and treatment perceptions, their correlation to demographics and AK/skin cancer history, and secondarily the influence of these perspectives on treatment and sunscreen use. MATERIALS AND METHODS: Participants completed questionnaires based on the Brief Illness Perception Questionnaire and statistical analysis was performed. RESULTS: In total, 208 AK patients were enrolled. A large proportion were poorly aware of the disease (41.4%), with less than half (43%) being familiar with AK. Patients were aware of the chronic nature of the disease and its correlation to sunlight regardless of demographic characteristics. The level of education played a role in disease awareness (p = 0.006), and treatment plan perception (p = 0.002). The increase in sunscreen protection after AK diagnosis was higher in women (p = 0.009) and younger patients (p = 0.044). Patients' concerns regarding treatment were mainly related to the duration (30%) and effectivity (25%). Dermatologists' statements highlighting that AK are precancerous lesions (86.2%) influenced patients' willingness for treatment. CONCLUSION: Improved awareness of AK is necessary to increase treatment seeking and compliance, regarding both treatment and sunscreen use. Dermatologists' statements may have critical influence on patients' decisions to receive treatment for AK.

Risk of Invasive Cutaneous Squamous Cell Carcinoma After Different Treatments for Actinic Keratosis: A Secondary Analysis of a Randomized Clinical Trial.

Importance: Treatment of actinic keratosis (AK) aims to prevent cutaneous squamous cell carcinoma (cSCC). However, whether AK can progress into invasive cSCC is a matter of debate, and little is known about the effect of treatment on preventing cSCC. Objectives: To evaluate the risk of invasive cSCC and factors that may contribute to increased risk in patients with multiple AKs. Design, Setting, and Participants: In this secondary analysis of a multicenter randomized clinical trial, 624 patients with a minimum of 5 AKs within an area of 25 to 100 cm2 on the head were recruited from the Department of Dermatology of 4 hospitals in the Netherlands. Long-term follow-up was performed from July 1, 2019, to December 31, 2020. Interventions: Patients were randomized to treatment with 5% fluorouracil, 5% imiquimod cream, methylaminolevulinate photodynamic therapy, or 0.015% ingenol mebutate gel. Main Outcomes and Measures: The primary outcome was the proportion of patients with invasive cSCC in the target area during follow-up. Secondary outcomes were the associations between risk of invasive cSCC and a priori defined potential prognostic factors, including type of treatment, severity of AK (Olsen grade), history of nonmelanoma skin cancer, and additional treatment. Results: Of the 624 patients (558 [89.4%] male; median age, 73 years [range, 48-94 years]) in the study, 26 were diagnosed with a histologically proven invasive cSCC in the target area during follow-up. The total 4-year risk of developing cSCC in a previously treated area of AK was 3.7% (95% CI, 2.4%-5.7%), varying from 2.2% (95% CI, 0.7%-6.6%) in patients treated with fluorouracil to 5.8% (95% CI, 2.9%-11.3%) in patients treated with imiquimod. In patients with severe AK (Olsen grade III), the risk was 20.9% (95% CI, 10.8%-38.1%), and the risk was especially high (33.5%; 95% CI, 18.2%-56.3%) in patients with severe AK who needed additional treatment. Conclusions and Relevance: In this secondary analysis of a randomized clinical trial, risk of invasive cSCC was highest in patients with Olsen grade III AK and was substantially increased in patients who received additional treatment. These patients should be closely followed up after treatment. Trial Registration: ClinicalTrials.gov Identifier: NCT02281682.