Pharmacotherapy of actinic keratosis: an update

Efficacy and safety of a thermal fractional skin rejuvenation system (Tixel) for the treatment of facial and/or scalp actinic keratoses

Actinic keratoses are common cutaneous lesions with a potential to progress to invasive squamous cell carcinoma. Therefore, treatment is crucial. The Tixel® is a noninvasive thermomechanical device designed to transfer heat to the upper dermis in a controlled manner according to a predetermined setting. This study aimed to evaluate the safety and efficacy of a thermomechanical fractional skin resurfacing technology for the treatment of facial and scalp actinic keratoses. A prospective, open-label, before-after study was conducted in a tertiary medical centre from May 2020 to April 2021. Patients presenting with facial/scalp actinic keratoses of mild-to-moderate thickness underwent 2 or 3 Tixel treatments (depending on clinical improvement), 3-4 weeks apart. The reduction in lesion count and overall improvement in appearance were assessed by clinical examination and digital photography. Findings were compared between baseline and follow-up at 3 months after the last treatment session. Patient satisfaction was evaluated by questionnaire, and adverse effects were documented. A total of 20 patients participated in the study. All completed 2-3 treatments and follow-up visits. Assessment of digital photographs was performed by 2 assessors blinded to the timepoint at which each photo was taken (before or after treatment). The average number of lesions at baseline was 9.8 (± 4.8) and the mean reduction in lesion count was 7.9 (± 4.4) (80.6%). Complete clearance was observed in 31.6% of patients. No adverse effects were noted during treatment and follow-up. Most patients reported being "very satisfied" or "satisfied" with the treatment results (85%) and experience (95%). Treating facial and scalp actinic keratoses with the Tixel device was found to be effective and safe.

Laser Resurfacing Monotherapy for the Treatment of Actinic Keratosis

Treating actinic keratosis (AK) and photodamaged skin is critical to reduce the risk of progression to skin cancer. Laser resurfacing for AK treatment is available as either lesion-directed or field therapy. Laser resurfacing removes the superficial epidermis and dermis containing actinic damage, promoting re-epithelialization of healthy skin. Although laser resurfacing has been explored as a modality for AK treatment in the literature, studies summarizing its efficacy in the treatment of AK are lacking. This review summarizes existing research on laser resurfacing as a monotherapy for AK treatment, highlighting the various laser resurfacing modalities available for AK treatment as well as their complications and efficacy in comparison to other therapies. Despite longer healing time, fully ablative laser resurfacing, including carbon dioxide and erbium-doped yttrium aluminum garnet were found to be more effective for AK treatment than fractional ablative techniques. Although some studies suggest laser resurfacing monotherapy as less efficacious than photodynamic therapy, and equally effective to 5-fluorouracil and 30% trichloroacetic acid, clinical trials of larger sample size are required to establish stronger evidence-based conclusions. Moreover, laser resurfacing used as lesion-directed therapy, as opposed to the usual field-therapy, requires further investigation.

Epigallocatechin Gallate Enhances MAL-PDT Cytotoxic Effect on PDT-Resistant Skin Cancer Squamous Cells

Photodynamic therapy (PDT) has been used to treat certain types of non-melanoma skin cancer with promising results. However, some skin lesions have not fully responded to this treatment, suggesting a potential PDT-resistant phenotype. Therefore, novel therapeutic alternatives must be identified that improve PDT in resistant skin cancer. In this study, we analyzed the cell viability, intracellular protoporphyrin IX (PpIX) content and subcellular localization, proliferation profile, cell death, reactive oxygen species (ROS) detection and relative gene expression in PDT-resistant HSC-1 cells. PDT-resistant HSC-1 cells show a low quantity of protoporphyrin IX and low levels of ROS, and thus a low rate of death cell. Furthermore, the resistant phenotype showed a downregulation of HSPB1, SLC15A2, FECH, SOD2 and an upregulation of HMBS and BIRC5 genes. On the other hand, epigallocatechin gallate catechin enhanced the MAL-PDT effect, increasing levels of protoporphyrin IX and ROS, and killing 100% of resistant cells. The resistant MAL-PDT model of skin cancer squamous cells (HSC-1) is a reliable and useful tool to understand PDT cytotoxicity and cellular response. These resistant cells were successfully sensitized with epigallocatechin gallate catechin. The in vitro epigallocatechin gallate catechin effect as an enhancer of MAL-PDT in resistant cells is promising in the treatment of difficult skin cancer lesions.

Current therapies for actinic keratosis

Actinic keratosis (AK) is a very common skin disease caused by chronic sun damage, which in 75% of cases arises on chronically sun-exposed areas, such as face, scalp, neck, hands, and forearms. AKs must be considered an early squamous cell carcinoma (SCC) for their probable progression into invasive SCC. For this reason, all AK should be treated, and clinical follow-up is recommended. The aims of treatment are: (i) to clinically eradicate evident and subclinical lesions, (ii) to prevent their evolution into SCC, and (iii) to reduce the number of relapses. Among available treatments, it is possible to distinguish lesion-directed therapies and field-directed therapies. Lesion-directed treatments include: (i) cryotherapy; (ii) laser therapy; (iii) surgery; and (iv) curettage. Whereas, field-directed treatments are: (i) 5-fluorouracil (5-FU); (ii) diclofenac 3% gel; (iii) chemical peeling; (iv) imiquimod; and (v) photodynamic therapy (PDT). Prevention plays an important role in the treatment of AKs, and it is based on the continuous use of sunscreen and protective clothing. This review shows different types of available treatments and describes the characteristics and benefits of each medication, underlining the best choice.

Efficacy of new class I medical device for actinic keratoses: a randomized controlled prospective study

BACKGROUND

The presence of Actinic Keratoses (AKs) represent the most important warning sign of subclinical ultraviolet radiation. Currently, the regular use of sunscreens is considered essential for the prevention of the development of AKs.

AIM

We evaluated the effectiveness of a new class I Medical Device (MD) for the prevention and treatment of AKs vs traditional sunscreen alone (SPF 100+).

METHODS

We conducted a randomized controlled prospective study in 90 Caucasian patients: 62 immunocompetent and 28 Organ Transplant Recipients (OTRs). We randomly assigned subjects to the MD group or sunscreen alone in a 1:1 assignment ratio. The patients have been reevaluated after three and six months.

RESULTS

In immunocompetent patients treated with MD, at the end of the study the reduction of the mean number of AKs was 54.7 vs. 9.43% with photoprotector. In OTRs, the global reduction was of 36.7% after MD use compared to 14.3% with the sunscreen. The prevalence of NMSCs, in the patients treated with MD, was 11.11 and 17.18 with sunscreen; the incidence was 19.7 in patients treated with MD and 32.1 in those treated with sunscreen.

CONCLUSION

The MD has demonstrated good efficacy in the reduction of visible AKs, encouraging its use also in high-risk category, like OTRs.

Evaluation of Resource Utilization and Treatment Patterns in Patients with Actinic Keratosis in the United States

OBJECTIVE

To compare health care resource utilization and treatment patterns between patients with actinic keratosis (AK) treated with ingenol mebutate gel (IngMeb) and those treated with other field-directed AK therapies.

METHODS

A retrospective, propensity-score-matched, cohort study compared refill/repeat and adding-on/switching patterns and outpatient visits and prescriptions (health care resource utilization) over 6 months in patients receiving IngMeb versus those receiving imiquimod, 5-fluorouracil, diclofenac sodium, and methyl aminolevulinate or aminolevulinic acid photodynamic therapy (MAL/ALA-PDT).

RESULTS

The final sample analyzed included four matched treatment cohort pairs (IngMeb and comparator; n = 790-971 per treatment arm). Refill rates were similar except for imiquimod (15% vs. 9% for imiquimod and IngMeb, respectively; P < 0.05). MAL/ALA-PDT treatment repetition rates were higher than IngMeb refill rates (20% vs. 10%; P < 0.05). Topical agent add-on/switch rates were comparable. PDT had higher switch rates than did IngMeb (5% vs. 2%; P < 0.05). The IngMeb cohort had a significantly lower proportion of patients with at least one AK-related outpatient visit during the 6-month follow-up than did any other cohort: versus imiquimod (50% vs. 66%; P < 0.0001), versus 5-fluorouracil (50% vs. 69%; P < 0.0001), versus diclofenac sodium (51% vs. 56%; P = 0.034), and versus MAL/ALA-PDT (50% vs. 100%; P < 0.0001). There were significantly fewer AK-related prescriptions among patients receiving IngMeb than among patients in other cohorts.

CONCLUSIONS

Results based on the first 6 months after treatment initiation suggested that most field-directed AK therapies had clinically comparable treatment patterns except imiquimod, which was associated with higher refill rates, and PDT, which was associated with significantly more frequent treatment sessions and higher switching rates. IngMeb was also associated with significantly fewer outpatient visits than were other field-directed therapies.

Sequential treatment of multiple actinic keratoses with solaraze and actikerall

Interest is increasing in the use of sequential or combined therapeutic modalities for spot or area treatment of actinic keratoses (AKs) to achieve complete sustained remission. For multiple lesions in a contained area, topical treatment offers less discomfort, better cosmesis and greater patient convenience than destructive/ablative techniques. Twelve patients with multiple grade I and II AK lesions of the scalp (cases 1–10) or the dorsum of the hand (cases 11 and 12), most with a history of recurrence, were treated with Solaraze gel (3% diclofenac sodium in 2.5% hyaluronic acid) twice daily for 12 weeks, followed by a 2-week treatment-free interval, then Actikerall cutaneous solution (5-fluorouracil 5 mg/g and salicylic acid 100 mg/g) once daily for up to 6 weeks as required. Sequential treatment provided complete (clinical and histological) clearance in 8/10 male patients. Two patients with numerous lesions had partial clearance (significant improvement) and the remaining few lesions were treated with erbium laser. Both female patients achieved complete clinical clearance with sequential treatment. Solaraze/Actikerall were well tolerated. A case of contact dermatitis with Solaraze resolved after discontinuation and the patient progressed to treatment with Actikerall. Local application site reactions resolved upon treatment completion. Topical lesion-directed sequential treatment with Solaraze/Actikerall is a rational approach to treat patients with multiple AKs. Sequential treatment produces excellent clearance rates which are accompanied by relevant improvement in patients’ quality of life.

Actinic keratosis: rationale and management

Actinic keratoses (AKs) are common skin lesions heralding an increased risk of developing squamous cell carcinoma (SCC) and other skin malignancies, arising principally due to excessive ultraviolet (UV) exposure. They are predominantly found in fair-skinned individuals, and increasingly, are a problem of the immunosuppressed. AKs may regress spontaneously, remain stable or transform to invasive SCC. The risk of SCC increases for those with more than 5 AKs, and the majority of SCCs arise from AKs. The main mechanisms of AK formation are inflammation, oxidative stress, immunosuppression, impaired apoptosis, mutagenesis, dysregulation of cell growth and proliferation, and tissue remodeling. Human papilloma virus has also been implicated in the formation of some AKs. Understanding these mechanisms guides the rationale behind the current available treatments for AKs. One of the main principles underpinning the management of AKs is that of field cancerization. Wide areas of skin are exposed to increasing amounts of UV light and other environmental insults as we age. This is especially true for the head, neck and forearms. These insults do not target only the skin where individual lesions develop, but also large areas where crops of AKs may appear. The skin between lesions is exposed to the same insults and is likely to contain as-yet undetectable preclinical lesions or areas of dysplastic cells. The whole affected area is known as the ‘field’. Management is therefore divided into lesion-directed and field-directed therapies. Current therapies include lesion-directed cryotherapy and/or excision, and topical field-directed creams: 5-fluorouracil, imiquimod, diclofenac, photodynamic therapy and ingenol mebutate. Combining lesion- and field-directed therapies has yielded good results and several novel therapies are under investigation. Treatment is variable and tailored to the individual making a gold standard management algorithm difficult to design. This literature review article aims to describe the rationale behind the best available therapies for AKs in light of current understanding of pathophysiology and epidemiology. A PubMed and MEDLINE search of literature was performed between January 1, 2000 and September 18, 2013. Where appropriate, articles published prior to this have been referenced. This is not a systematic review or meta-analysis, but aims to highlight the most up to date understanding of AK disease and its management.

Management of actinic keratosis

Actinic keratoses are common, often multiple, epidermal lesions found mainly on the sun-exposed skin of fair-skinned middle-aged and older people.(1) Over time, lesions may remain unchanged or may proliferate, regress, reappear or develop into squamous cell carcinoma (SCC).(2) Detectable (spot) lesions are often associated with alteration of the surrounding skin (field) where subclinical lesions might be present.(2) Interventions may target individual or multiple lesions or a whole field.(2) Here, we update our previous review(3) on the prevention and treatment of actinic keratoses, focusing on the licensed treatments most commonly used in the UK and recommended in UK guidelines.

Use of photodynamic therapy for treatment of actinic keratoses in organ transplant recipients

Solid organ transplant recipients are predisposed to actinic keratoses (AK) and nonmelanoma skin cancers, owing to the lifelong immunosuppression required. Today, increasing numbers of organ transplants are being performed and organ transplant recipients (OTRs) are surviving much longer. Photodynamic therapy (PDT) is proving a highly effective treatment modality for AK amongst this susceptible group of patients. Following an overview of the pathogenesis of AK amongst OTRs, the authors review current safety and efficacy data and how this relates to the role of PDT for the treatment of AK in OTRs.