Actinic Keratosis Color and Its Associations: A Retrospective Photographic, Dermoscopic, and Histologic Evaluation.

BACKGROUND AND OBJECTIVE: Actinic keratoses (AKs) have been described with varying color and morphology; however, no reports have demonstrated associations between color, vasculature, and inflammation. In this retrospective study, we analyze the clinical, dermoscopic, and histopathologic features of AKs to elucidate this relationship. METHODS: A retrospective search for patients diagnosed with AK between January 2018 and October 2019 was performed. Clinical and dermoscopic photographs and pathology slides for all included subjects were reviewed. RESULTS: Forty-nine images and histopathology slides were analyzed. Dermoscopy of white AKs demonstrated scale and absence of erythema with corresponding absence of inflammation on histopathology. Dermoscopy of brown AKs revealed pseudonetwork, absent scale, and a variable vessel pattern with pigment incontinence and absence of inflammation on histopathology. Red AKs had a distinct polymorphous vessel pattern and presence of erythema on dermoscopy. On histopathology, about half of samples showed increased vascularity and variable inflammation. Pink AK dermoscopy revealed a presence of erythema with corresponding presence of inflammation on histopathology. CONCLUSION: This report adds to our understanding of AKs and confirms that, in general, the pinker or redder the AK, the more prominent the inflammatory infiltrate and vasculature, respectively. Dermatologists should continue to use their diagnostic skills to successfully diagnose and triage AKs.

Use of Topical and Systemic Retinoids in Solid Organ Transplant Recipients: Update and Review of the Current Literature.

BACKGROUND: Solid organ transplant recipients (SOTRs) are at an increased risk of epithelial malignancies, mainly squamous cell carcinoma, and its precursor lesions such as actinic keratoses, warts, and porokeratosis, which may respond to retinoid therapy. OBJECTIVE: To review the published evidence on the efficacy and safety of topical and systemic retinoids for the treatment and prophylaxis of malignant and premalignant conditions that mostly afflict SOTRs. MATERIALS AND METHODS: Systematic review of the literature to summarize the level of evidence and grade of recommendation for retinoid therapy with emphasis in the SOTR population. RESULTS: Acitretin has the highest strength of recommendation (Grade A) for prophylaxis of nonmelanoma skin cancer (NMSC) and treatment and prophylaxis of actinic keratoses in SOTR. In nonimmunosuppressed patients, acitretin and isotretinoin have a Grade B recommendation for treatment of recalcitrant warts. Topical retinoids have not shown efficacy in preventing NMSC in immunocompetent patients. CONCLUSION: Retinoids constitute a highly efficacious alternative for the management of the most common conditions that affect SOTRs. Acitretin has the most robust evidence for chemoprophylaxis in SOTRs. Knowledge about the specific indications and expected side effects of topical and systemic retinoids may help optimize their therapeutic potential.

5-Aminolevulinic acid photodynamic therapy with and without Er:YAG laser for actinic keratosis: Changes in immune infiltration.

INTRODUCTION: Ultraviolet light induced DNA damage, combined with immunosuppression and inflammation are involved in the pathogenesis of actinic keratosis. Photodynamic therapy not only destroys dysplastic cells via tissue destruction and vascular shutdown, but also induces an acute local inflammatory response and activates both the innate and adaptive immune system. In our current work we aimed to compare immunohistochemistry features of inflammatory infiltrate of actinic keratoses after 5-aminolevulinic acid photodynamic therapy with or without Er:YAG laser resurfacing. METHODS: Eleven patients with multiple actinic keratosis on the scalp, face, hands or forearms were treated by conventional and Er:YAG laser assisted 5-aminolevulinic acid PDT in split-site manner. Biopsies of AKs were taken before, 48 h and 3 months after the treatment. CD3, CD4, CD8, CD1a, Ki67 and p53 expressions were analyzed by immunohistochemical methods. RESULTS: The number of p53 and Ki67 positive cells decreased significantly 3 months after treatment, but the abnormal cells were not eliminated totally. The number of CD1a+ Langerhans cells significantly decreased 48 h after both treatments, while CD8+ T cell count was significantly lower 3 months after Er:YAG laser assisted photodynamic therapy. However, the number of CD3+ and CD4+ T cells were not changed significantly 48 h and 3 months later. CONCLUSIONS: One session of 5-aminolevulinic acid photodynamic therapy even with Er:YAG laser pretreatment could not terminate actinic damage totally. Photodynamic therapy induced immunological changes. However further investigations are needed to answer how the composition of actinic keratosis' immune infiltrate influence the effect of photodynamic therapy.

Disruption of latent HIV in vivo during the clearance of actinic keratosis by ingenol mebutate.

Actinic keratosis (AK) is a precancerous skin lesion that is common in HIV-positive patients. Without effective treatment, AKs can progress to squamous cell carcinoma. Ingenol mebutate, a PKC agonist, is a US Food and Drug Administration-approved (FDA-approved) topical treatment for AKs. It can induce reactivation of latent HIV transcription in CD4+ T cells both in vitro and ex vivo. Although PKC agonists are known to be potent inducers of HIV expression from latency, their effects in vivo are not known because of the concerns of toxicity. Therefore, we sought to determine the effects of topical ingenol mebutate gel on the HIV transcription profile in HIV-infected individuals with AKs, specifically in the setting of suppressive antiretroviral therapy (ART). We found that AKs cleared following topical application of ingenol mebutate and detected marginal changes in immune activation in the peripheral blood and in skin biopsies. An overall increase in the level of HIV transcription initiation, elongation, and complete transcription was detected only in skin biopsies after the treatment. Our data demonstrate that application of ingenol mebutate to AKs in ART-suppressed HIV-positive patients can effectively cure AKs as well as disrupt HIV latency in the skin tissue microenvironment in vivo without causing massive immune activation.

Imiquimod 3.75% for field-directed therapy of actinic keratosis: results of a prospective case-series study in Greece.

BACKGROUND: Imiquimod 3.75% is a field-directed treatment for actinic keratosis that can detect and treat clinical and subclinical lesions across an entire sun-exposed field. The detection of subclinical lesions is evidenced by an increase in lesions to the maximum lesion count during treatment (Lmax ). We report clinical outcomes for the first 15 patients treated with imiquimod 3.75% in daily clinical practice in Greece. METHODS: Fifteen patients with actinic keratosis lesions were treated with imiquimod 3.75% in an outpatient setting in two 2-week treatment cycles separated by a 2-week treatment-free interval. Actinic keratosis lesions were counted before treatment, at the end of the first treatment cycle (Week 2; Lmax ), and 2 weeks after the second treatment cycle (Week 8). Local skin reactions (LSR) were also evaluated at Weeks 2 and 8. RESULTS: The median baseline actinic keratosis lesion count was 25, which increased to a median Lmax of 29 at Week 2 and decreased to a median of 5 at Week 8. The median percentage and absolute reduction in actinic keratosis lesions from Lmax to Week 8 were 87% and 23%, respectively. Most of the LSR were mild-to-moderate in intensity at Week 2 and had resolved by Week 8. CONCLUSION: Imiquimod 3.75% effectively detected and cleared both the clinical and subclinical actinic keratosis lesions across the entire sun-exposed field in this cohort of Greek patients. Treatment was well tolerated.

Topical resiquimod dosing regimens in patients with multiple actinic keratoses: a multicentre, partly placebo-controlled, double-blind clinical trial.

BACKGROUND: Topical immune response modifiers are established for actinic keratosis (AK) treatment and efforts are underway to make further improvements to their efficacy and safety. OBJECTIVES: To investigate the optimal dosing regimens of the Toll-like receptor 7/8 agonist resiquimod in terms of efficacy, safety and tolerability. METHODS: In a multicentre, partly placebo-controlled, double-blind clinical trial, we randomized 217 patients with AK lesions to 0·03% resiquimod gel once-daily application three times per week for 4 weeks or seven times within 2 weeks or five times for 1 week (arms 1/2/3) followed by a treatment-free interval of 8 weeks and one repetition of the cycle. In two additional arms (arms 4/5), patients applied either resiquimod gel 0·01% or 0·03% three times per week up to a biological end point defined by skin erosion or for a maximum duration of 8 weeks. Clearance was assessed clinically and histologically. RESULTS: Complete clinical clearance ranged from 56% to 85% with the highest rate observed in arm 2. Resiquimod 0·03% gel was more effective than 0·01% gel. Clearance rates in arms 1/2/3 were comparable and higher than with placebo and were reached with 24, 14 and 10 gel applications, respectively. Overall, 128 patients (59%) experienced treatment-related adverse reactions. CONCLUSIONS: Resiquimod 0·03% gel is more effective than 0·01% gel. From the perspectives of safety and tolerability, the lower concentration and shorter duration are preferable. The clinical response in arms 2/3 was reached with fewer gel applications. The dosing regimens that used the biological end point (arms 4/5) proved equally efficacious as predefined treatment durations and may therefore be suitable for personalized AK treatment.

Local interventions for actinic keratosis in organ transplant recipients: a systematic review.

BACKGROUND: Actinic keratosis (AK) in organ transplant recipients (OTRs) has a high risk of progressing to invasive squamous cell carcinoma of the skin. Thus, early and consequent treatment of AKs is warranted in OTRs. OBJECTIVES: To summarize the current evidence for nonsystemic treatments of AKs in OTRs. METHODS: We performed a systematic literature search in MEDLINE, Embase and the Cochrane Central Register of Controlled Trials (CENTRAL) and hand-searched pertinent trial registers up to 22 August 2018. Randomized controlled trials (RCTs) evaluating nonsystemic interventions for AKs in OTRs were included. The risk of bias was estimated using the Cochrane Risk of Bias Tool. RESULTS: Of 663 records initially identified, eight RCTs with 242 OTRs were included in a qualitative synthesis. Most studies evaluated methyl aminolaevulinate photodynamic therapy (MAL-PDT), followed by ablative fractional laser (AFXL) and diclofenac sodium 3% in hyaluronic acid, imiquimod 5% cream and 5-fluorouracil 5% cream (5-FU). MAL-PDT showed the highest rates of participant complete clearance (40-76·4%), followed by imiquimod (27·5-62·1%), diclofenac (41%) and 5-FU (11%). Similar results were observed for lesion-specific clearance rates. Treatment with AFXL alone revealed low lesion clearance (5-31%). Local skin reactions were most intense in participants treated with a combination of AFXL and daylight MAL-PDT. There were no therapy-related transplant rejections or worsening of graft function in any trial. The overall risk of bias was high. CONCLUSIONS: Limited evidence is available for the treatment of AKs in OTRs. MAL-PDT is currently the best-studied intervention. Lesion-specific regimens may not be sufficient to achieve disease control. Field-directed regimens are preferable in this high-risk population.

Immunological effects of photodynamic therapy in the treatment of actinic keratosis and squamous cell carcinoma.

The use of photodynamic therapy is extensive, due to its antitumoral, antibacterial and photorejuvenation effects. It destroys tumor via direct cell destruction and indirectly via vascular shutdown, induction of acute local inflammatory response and activation of the immune system. Both innate and adaptive immune cells are involved in the immunological effects of photodynamic therapy. In addition to UV-induced DNA damage, inflammation and immunosuppression are also essential elements in the pathogenesis of actinic keratosis. Both immunosuppression induced by UV and defective immune response to dysplastic keratinocytes may be the target of photodynamic therapy to eliminate actinic keratosis. These elements are discussed in the present review, highlighting the possible mechanism of photodynamic therapy to effectively treat actinic keratosis.

Evaluation of T-lymphocyte subpopulations in actinic keratosis, in situ and invasive squamous cell carcinoma of the skin.

BACKGROUND: Tumor infiltrating lymphocytes (TILs) represent important regulators of carcinogenesis. Cutaneous invasive squamous cell carcinoma (inSCC) develops through precursor lesions, namely in situ squamous cell carcinoma (isSCC) and actinic keratosis (AK), representing a natural model of carcinogenesis. The study evaluates TIL subpopulations in inSCC and its precursors by comparing 2 semiquantitative scoring systems, and assesses the presence of regulatory T-cells (Tregs) in these lesions. METHODS: Paraffin sections from 33 cases of AK, 19 isSCCs and 34 inSCCs with adjacent precursor lesions or normal skin (NS) were immunostained for CD3, CD4, CD8 and Foxp3. TIL subgroups were evaluated by the semiquantitative Klintrup-Mäkinen (K-M) score, and by a more detailed modification of this system. Treg counts were assessed by image analysis quantification. RESULTS: An increase of all TIL subpolulations from precursor lesions toward inSCC was shown by both scoring systems. Treg counts progressively increased from NS to AK and isSCC, but decreased in inSCC. Tregs were more numerous in pT2 and around indolent inSCCs compared to T1 and aggressive subtypes. CONCLUSIONS: T-cells and cytotoxic T-cells progressively increase in cutaneous squamous cell carcinogenesis, while Treg counts diminish in inSCC. The K-M score is an appropriate, easily applicable TIL scoring system in cutaneous inSCC.

Increased number of mast cells in the dermis in actinic keratosis lesions effectively treated with imiquimod.

Actinic keratosis (AK) is a cutaneous cancer in situ which develops as a result of excessive exposure to ultraviolet (UV). Toll-like receptor (TLR)7 agonist imiquimod is a topical immune response modifier and is effective for the treatment of non-melanoma skin cancers. Recently, the diagnostic role of the dermatoscope has been reported in the course of treatment of AK. In addition, mast cells are now considered to contribute to both the innate and adaptive immune systems in topical imiquimod therapy. We assessed the effect of imiquimod treatment by dermatoscopic and immunohistochemical findings in 14 patients with a total of 21 AK lesions. With the dermatoscope, though the mean erythema score was not significantly different between the cured lesions and the unresponsive lesions, the erythema/red pseudo-network ("strawberry") pattern was decreased significantly in the cured lesions. By immunohistochemistry, the number of Ki-67-positive proliferative cells in the epidermis was decreased and that of CD117-positive mast cells in the dermis was increased in the responding lesions. To the best of our knowledge, this is the first study demonstrating that the number of mast cells in the dermis was increased in AK lesions effectively treated with imiquimod. Our present result suggests that mast cells may contribute an antitumor effect in human skin treated with topical imiquimod.

Randomized trial of calcipotriol combined with 5-fluorouracil for skin cancer precursor immunotherapy.

BACKGROUND: Actinic keratosis is a precursor to cutaneous squamous cell carcinoma. Long treatment durations and severe side effects have limited the efficacy of current actinic keratosis treatments. Thymic stromal lymphopoietin (TSLP) is an epithelium-derived cytokine that induces a robust antitumor immunity in barrier-defective skin. Here, we investigated the efficacy of calcipotriol, a topical TSLP inducer, in combination with 5-fluorouracil (5-FU) as an immunotherapy for actinic keratosis. METHODS: The mechanism of calcipotriol action against skin carcinogenesis was examined in genetically engineered mouse models. The efficacy and safety of 0.005% calcipotriol ointment combined with 5% 5-FU cream were compared with Vaseline plus 5-FU for the field treatment of actinic keratosis in a randomized, double-blind clinical trial involving 131 participants. The assigned treatment was self-applied to the entirety of the qualified anatomical sites (face, scalp, and upper extremities) twice daily for 4 consecutive days. The percentage of reduction in the number of actinic keratoses (primary outcome), local skin reactions, and immune activation parameters were assessed. RESULTS: Calcipotriol suppressed skin cancer development in mice in a TSLP-dependent manner. Four-day application of calcipotriol plus 5-FU versus Vaseline plus 5-FU led to an 87.8% versus 26.3% mean reduction in the number of actinic keratoses in participants (P < 0.0001). Importantly, calcipotriol plus 5-FU treatment induced TSLP, HLA class II, and natural killer cell group 2D (NKG2D) ligand expression in the lesional keratinocytes associated with a marked CD4+ T cell infiltration, which peaked on days 10-11 after treatment, without pain, crusting, or ulceration. CONCLUSION: Our findings demonstrate the synergistic effects of calcipotriol and 5-FU treatment in optimally activating a CD4+ T cell-mediated immunity against actinic keratoses and, potentially, cancers of the skin and other organs. TRIAL REGISTRATION: ClinicalTrials.gov NCT02019355. FUNDING: Not applicable (investigator-initiated clinical trial).

Biological Effects of Ingenol Mebutate Gel in Moderate to Severe Actinic Fields Assessed by Reflectance Confocal Microscopy: A Phase I Study.

Ingenol mebutate represents a topical treatment for fields with actinic keratosis (AK). The biological effects of ingenol mebutate in AK, subclinical (SC)-AK, and reference-skin were assessed and graded by in vivo reflectance confocal microscopy (RCM) and histology. Patients with AK and SC-AK lesions in one 25 cm2 field on hands or forearms, and with an area of reference skin on the inner upper arm, were included. The two fields were each treated with ingenol mebutate 0.05% gel (n=16), or vehicle (n=8), on 2 consecutive days; clinical and RCM assessments were performed on days 1, 2, 3, 8, and 57, and biopsies on day 3. Local skin responses were more pronounced in AK fields (6.1 (mean) ± 2.6 (SD)) compared with reference skin (3.5 ± 1.5). The clinical AK lesion reduction was 43.8% and 6.3% with ingenol mebutate and vehicle, respectively. RCM and histology evaluations showed that ingenol mebutate induced a significant pronounced cell death and immune response in AK and SC-AK lesions, compared with reference skin. Ingenol mebutate induced RCM-measured reduction in (investigator-1/investigator-2): AK lesions (34/28%), SC-AK lesions (72/56%), and solar elastosis in AK fields (mean, -0.22/-0.25). In conclusion, ingenol mebutate showed selective pronounced biological responses in AK and SC-AK as compared with reference skin.

J Drugs Dermatol. 2016;15(10):1181-1189.

Photodamage: all signs lead to actinic keratosis and early squamous cell carcinoma.

Ultraviolet (UV) radiation is likely to drive the initiation and progression of skin cancer from actinic keratosis to squamous cell carcinoma. Signs of photodamage occur at multiple steps. UV radiation damages many cellular constituents, including lipids, proteins and DNA, all of which are likely to contribute to UV-induced skin cancer. Two biological events culminating from photodamage are mutations in the genes critical to the control of cell division, differentiation and invasion and immunosuppression. DNA photodamage, if unrepaired prior to cell division, can result in the incorporation of an incorrect nucleotide into newly synthesised DNA. Mutations in critical genes contribute to carcinogenesis. Photodamage to proteins such as those involved in DNA repair or proteins or lipids involved in cellular signalling can interfere with this repair process and contribute to mutagenesis. Mutations in key genes, including TP53, BRM, PTCH1, and HRAS, contribute to skin carcinogenesis. UV also damages immunity. Photodamage to DNA and signalling lipids as well as other molecular changes are detrimental to the key cells that regulate immunity. Photodamaged dendritic cells and altered responses by mast cells lead to the activation of T and B regulatory cells that suppress immunity to the protein products of UV-mutated genes. This stops the immune response from its protective function of destroying mutated cells, enabling the transformed cells to progress to skin cancer. UV appears to play a pivotal role at each of these steps, and therefore, signs of photodamage point to the development of skin cancer.

Do actinic keratoses and superficial squamous cell carcinomas have a specific immunoprofile?

The link between actinic keratosis (AK), squamous cell carcinoma (SCC), and a fully functional immune system has been frequently observed but is poorly understood. Elderly and immunosuppressed individuals and those with weakened immune systems caused by disease are all at increased risk of developing AK and/or SCC. This risk is particularly enhanced at sites that receive high levels of ultraviolet exposure from the sun, which is thought to be a driver of DNA mutations in the skin. The immune system appears to play a key role in preventing these mutations from progressing to malignant disease. AK is often considered to be a pre-cancerous lesion that may develop into SCC. However, the vast majority of AKs, in contrast to SCCs, regress naturally or in response to immune-modifying medications. The cellular mechanisms involved in this immune-based process remain elusive and raise the following question: does the immune make-up or immune functionality within AK differ fundamentally from that within SCC? This chapter will outline the skin as a site of considerable immunological activity, highlight the consequences of dysregulated immune activity in the skin, and discuss what little we know of immune infiltrates and their associated functions within AK and SCC.

[Organ transplant recipients need intensive control and treatment of skin cancer]. / Organtransplanterede patienter har behov for intensiv kontrol og behandling af hudcancer.

The risk of non-melanoma skin cancer (NMSC) and in particular squamous cell carcinoma is significantly increased in organ transplant recipients due to long-term treatment with immunosuppressives. Dermatologic management in the form of a multidisciplinary approach, including patient education, skin surveillance and early treatment of premalignant and malignant lesions is recommended. Field-directed rather than lesional therapy is preferred for actinic keratosis in field-cancerized skin; and high-efficacy therapies are recommended in NMSC due to an increased risk of recurrences and metastases.

Network meta-analysis of the outcome 'participant complete clearance' in nonimmunosuppressed participants of eight interventions for actinic keratosis: a follow-up on a Cochrane review.

The conclusions of pairwise meta-analyses of interventions for actinic keratosis (AK) are limited due to the lack of direct comparison between some interventions. Consequently, we performed a network meta-analysis for eight treatments [5-aminolaevulinic acid (ALA)-photodynamic therapy (PDT), cryotherapy, diclofenac 3% in 2·5% hyaluronic acid (DCF/HA), 5-fluorouracil (5-FU) 0·5% or 5·0%, imiquimod (IMI) 5%, ingenol mebutate (IMB) 0·015-0·05%, methyl aminolaevulinate (MAL)-PDT and placebo/vehicle (including placebo-PDT)] to determine their relative efficacies. As part of a prior Cochrane systematic review, different databases and grey literature were searched for randomized controlled trials up to April 2012. The inclusion criteria were parallel-group studies with nonimmunosuppressed participants: (i) reporting 'participant complete clearance' and (ii) comparing at least two of the interventions. Thirty-two publications met the criteria and they included the following number of individual or pooled studies (n) and total number of participants (N) for the different interventions: 5-FU 0·5% (n = 4, N = 169), 5-FU 5·0% (n = 2, N = 44), ALA-PDT (n = 6, N = 739), cryotherapy (n = 2, N = 174), DCF/HA (n = 5, N = 299), IMI (n = 14, N = 1411), IMB (n = 3, N = 560), MAL-PDT (n = 7, N = 557) and placebo (n = 32, N = 2520). Network analyses using a random-effects Bayesian model were carried out with the software ADDIS v1.16.1. The interventions were ranked as follows based on calculated probabilities and odd ratios: 5-FU > ALA-PDT ≈ IMI ≈ IMB ≈ MAL-PDT > cryotherapy > DCF/HA > placebo. This efficacy ranking was obtained based on the current available data on 'participant complete clearance' from randomized controlled trials and the analysis model used. However, several other factors should also be considered when prescribing a treatment for AK.