Imiquimod 3.75% in actinic keratosis: efficacy in patients with and without rest periods during treatment

Safety and efficacy of the combination of cryotherapy and photodynamic modalities with imiquimod in patients with actinic keratosis: a systematic review and meta-analysis

INTRODUCTION

Actinic keratosis (AK) is an intraepithelial tumor that, in most cases, arises in chronically sun-exposed areas. The combination of cryotherapy and photodynamic modalities with imiquimod has been proven to be a potential therapeutic option for AKs. However, there is no comprehensive systematic study that discussed this concept in literature taking into consideration both efficacy and safety.

EVIDENCE ACQUISITION

We performed a comprehensive search of the literature for studies assessing the efficacy and toxicity of the combinatorial tripartite regimen, consisting of cryotherapy and photodynamic modalities with imiquimod in AK. Metanalysis was performed using comprehensive meta-analysis version 3.0.

EVIDENCE SYNTHESIS

After the screening of 1031 studies, five studies were included. Two trials compared the effect of imiquimod/cryotherapy versus cryotherapy alone or versus cryotherapy/vehicle. Our meta-analysis indicated that imiquimod/cryotherapy effectively induces complete clinical clearance in patients with AKs (OR: 6.26; 95%CI: 1.56-24.1; P=0.01). Moreover, another two studies, which were not meta-analyzed, indicated a substantial clinical clearance in the number of AK lesions in the imiquimod plus photodynamic therapy arm as compared to 5% imiquimod or PDT alone. No serious systemic adverse events were reported in all the treatment arms.

CONCLUSIONS

Combined PDT or cryotherapy with imiquimod is more effective in the complete recovery of AK than treatment with imiquimod alone.

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.

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.

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 (L_max). 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; L_max), 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 L_max 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 L_max 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.

A 12-Day Course of Imiquimod 5% for the Treatment of Actinic Keratosis: Effectiveness and Local Reactions

INTRODUCTION AND OBJECTIVES

Imiquimod is an excellent option for patients with actinic keratosis, although its use may be limited by the long course of treatment required (4 weeks) and the likelihood of local skin reactions. The objectives of the present study were to demonstrate the effectiveness of a 12-day course of imiquimod 5% for the treatment of actinic keratosis and to examine the association between treatment effectiveness and severity of local reactions.

PATIENTS AND METHODS

We included patients with at least 8 actinic keratoses treated with imiquimod 5% cream for 12 consecutive days. Local reactions were classified as mild, moderate, or severe. The statistical analysis of the association between local reactions and clinical response was based on the Pearson χ² test and the Spearman rank correlation test.

RESULTS

Sixty-five patients completed the study. Complete response was recorded in 52.3% and partial response in 75.4%. We found a statistically significant association between severity of the local reaction and response to treatment in both the Pearson χ² test and the Spearman rank correlation test.

CONCLUSIONS

A 12-day course of imiquimod 5% proved effective for the treatment of actinic keratosis. Severity of local reactions during treatment was correlated with clinical response.