Efficacy of imiquimod 3.75% from Lmax according to the number of actinic keratosis lesions

BACKGROUND

Imiquimod 3.75% reduces 92.2% of all actinic keratosis (AK) lesions, assumed to include both subclinical and clinical lesions, across a large sun-exposed field such as the full face or balding scalp.

OBJECTIVE

To evaluate the efficacy of imiquimod 3.75% using the reduction in lesions from Lmax (the maximum lesion count during treatment) in subgroups of patients with low and high AK lesion counts.

METHODS

Patients from two 14-week, placebo-controlled, double-blind studies were subgrouped according to whether they had ≤ 10 or >10 AK lesions at baseline. Treatment was applied to the full face or balding scalp during two 2-week treatment cycles separated by a 2-week treatment-free interval.

RESULTS

Overall, 167 patients had ≤ 10 lesions and 152 patients had >10 AK lesions at baseline. With imiquimod 3.75%, the median percentage reduction in AK lesions from Lmax to end of study was similar in patients with ≤ 10 and >10 baseline lesions (91.5% and 93.0% respectively). The median absolute reduction in AK lesions from Lmax to end of study was 24.0 for patients with >10 baseline lesions and 10.0 for those with ≤ 10 baseline lesions. The median percentage and absolute reductions in lesions from Lmax were significantly greater with imiquimod 3.75% vs. placebo (P < 0.0001).

CONCLUSIONS

Imiquimod 3.75% is effective regardless of disease severity as shown in this study by the reduction of over 90% of lesions from Lmax in patients with low or high AK lesion counts.

The natural history of actinic keratosis: a systematic review

Knowledge about the development of untreated actinic keratosis (AK) and risk of progression into squamous cell carcinoma (SCC) is important. Therefore, we set out to synthesize primary data on the natural history of AK. We carried out a systematic literature search (Medline, Medline in Process, Embase, Cochrane) of studies on the natural course of AK, regarding (i) progression and regression rates per lesion-year, (ii) changes in total lesion counts over time, and (iii) spontaneous field regression and recurrence rates, taking into account studies on participants without immunosuppression and history of skin cancer, immunosuppressed patients and participants with a history of skin cancer and sunscreen use. Twenty-four eligible studies were identified providing data on at least one of the outcomes. Progression rates of AK to SCC ranged from 0% to 0·075% per lesion-year, with a risk of up to 0·53% per lesion in patients with prior history of nonmelanoma skin cancer. Rates of regression of single lesions ranged between 15% and 63% after 1 year. The data available on recurrence rates of single lesions 1 year after regression indicate a recurrence rate of 15-53%. Data on the relative change of total AK count over time are heterogeneous, and range from -53% to +99·1%. Spontaneous complete field regression rates range from 0% to 21%, with recurrences in 57%. In general, the available data are limited. Important methodological limitations apply. Currently, no reliable estimates concerning the frequency of AK developing into invasive carcinoma can be given, and further studies are needed.

Potential impact of interventions resulting in reduced exposure to ultraviolet (UV) radiation (UVA and UVB) on skin cancer incidence in four European countries, 2010-2050

BACKGROUND

Behavioural interventions to reduce exposure to ultraviolet radiation (UVR) can reduce risk of skin cancer.

OBJECTIVES

To integrate the data and to evaluate the impact of interventions to limit exposure to UVR on skin cancer incidence in four selected countries.

METHODS

Using PREVENT, a dynamic simulation model, we modelled the potential for skin cancer prevention in four European countries under various scenarios to avoid damage by UVR.

RESULTS

In general, the most effective interventions were those aimed at protecting people during outdoor work and outdoor hobbies against the harmful effects of UVR, and combinations of several interventions. These could in theory lead to reductions of up to 45% in skin cancer cases projected for the year 2050.

CONCLUSIONS

The scope for prevention depends on the prevalence of the risk factors in the different countries, as well as the associated risk factors and time lags modelled.

Low-dose 5-fluorouracil in combination with salicylic acid as a new lesion-directed option to treat topically actinic keratoses: histological and clinical study results

BACKGROUND

Actinic keratoses (AKs) arise after chronic sun exposure. Because long-term ultraviolet (UV) damage may induce proliferation of atypical keratinocytes, treatment of AKs is recommended.

OBJECTIVES

To compare 5-fluorouracil 0·5%/salicylic acid 10·0% [low-dose 5-FU/SA (Actikerall®)] with diclofenac 3% in hyaluronic acid (diclofenac HA) and vehicle for the treatment of AKs.

METHODS

This was a randomized, placebo-controlled, double-blind, parallel-group, multicentre trial. Patients received topical low-dose 5-FU/SA once daily, its vehicle or diclofenac HA twice daily for a maximum of 12 weeks. The final evaluation was at week 20. The primary objectives were to demonstrate the histological clearance rate of one predefined lesion. The secondary objectives were the improvement of treated lesions, tolerability and safety.

RESULTS

There were 470 patients with 4-10 AK lesions each (grade I or II) on the face/forehead or bald scalp included in the study. Low-dose 5-FU/SA was superior to diclofenac HA (P < 0·01) and vehicle (P < 0·0001) for histological clearance of one representative lesion 8 weeks post-treatment. In 72·0%, 59·1% and 44·8% of patients in the low-dose 5-FU/SA, diclofenac HA and vehicle groups, respectively, the week-20 biopsy revealed no AKs. Significantly more lesions were cleared with low-dose 5-FU/SA (74·5%) compared with diclofenac HA (54·6%; P < 0·001) or vehicle (35·5%; P< 0·001). Low-dose 5-FU/SA was superior in terms of complete clinical clearance: 55·4%, vs. diclofenac HA (32·0%, P < 0·001) and vehicle (15·1%P < 0·001). Application-site disorders (mainly burning and inflammation) were more frequent with low-dose 5-FU/SA but mainly of mild to moderate intensity.

CONCLUSIONS

Topical low-dose 5-FU/SA demonstrated higher histological and clinical clearance rates vs. diclofenac HA or vehicle. Low-dose 5-FU/SA is an effective lesion-directed treatment for AKs.

Distribution of bacteria in the epidermal layers and hair follicles of the human skin

Previous studies over recent years have revealed the presence of a resident bacterial population in the human skin throughout the entire body. However, the localization and composition of the bacteria within the epidermis and the skin appendages have not been fully investigated. Using differential tape stripping, cyanoacrylate skin surface biopsies and mapping of hair follicles, bacteria on the forearms of study participants were isolated, mapped, cultured and identified with respect to their origin within the epidermis and the hair follicles. Our studies showed that 85% of the bacteria were found within the first 6 corneocyte layers and roughly 25% of the cutaneous bacterial population were localized within the hair follicles. The microbial flora of the skin between individuals is subject to considerable fluctuations. Micrococcaceae represent the biggest fraction of hair-follicle-associated bacteria. The techniques developed for this study allowed us to selectively investigate the bacterial population within the hair follicles. Our results point out the role of skin appendages as potential microbial reservoirs and the need to develop new antiseptic formulations that sufficiently penetrate into the hair follicles.

A case-control study of betapapillomavirus infection and cutaneous squamous cell carcinoma in organ transplant recipients

We examined the association between betapapillomavirus (betaPV) infection and cutaneous squamous cell carcinoma (SCC) in organ transplant recipients. A total of 210 organ transplant recipients with previous SCC and 394 controls without skin cancer were included. The presence of 25 betaPV types in plucked eyebrow hairs was determined using a human papillomavirus (HPV) DNA genotyping assay, and antibodies for the 15 most prevalent betaPV types were detected using multiplex serology. We used multivariate logistic regression models to estimate associations between various measures of betaPV infection and SCC. BetaPV DNA was highly prevalent (>94%) with multiple types frequently detected in both groups. We found a significant association between SCC and the concordant detection of both antibodies and DNA for at least one betaPV type (adjusted OR 1.6; 95% CI 1.1;2.5). A borderline-significant association with SCC was found for HPV36 (adjusted OR 2.4; CI 1.0;5.4), with similar associations for HPV5, HPV9 and HPV24. These data provide further evidence of an association between betaPV infection and SCC in organ transplant recipients. Confirmation of a betaPV profile predictive of risk for SCC may pave the way for clinically relevant pretransplant HPV screening and the development of preventive and therapeutic HPV vaccination.

Non-invasive diagnosis and monitoring of actinic cheilitis with reflectance confocal microscopy

BACKGROUND

Actinic cheilitis (AC) represents the equivalent of actinic keratosis on the lip. Various treatment modalities are available and the efficacy of diclofenac in hyaluronic acid has recently been described. Reflectance confocal microscopy (RCM) is a non-invasive imaging technique which has recently been applied for the diagnosis of actinic keratoses. Herein, we describe the applicability of RCM for the diagnosis of AC and for monitoring of treatment response of AC to diclofenac in hyaluronic acid.

METHODS

Ten Caucasian patients with clinical suspicion for AC were included in this study. To obtain a non-invasive diagnosis, RCM was performed at baseline, followed by biopsy and respective confocal-histopathological correlation. Six patients with a histological diagnosis of AC were treated with diclofenac in hyaluronic acid, whereby monitoring was performed by RCM.

RESULTS

Reflectance confocal microscopy was able to correctly identify 6/7 cases of AC and 3/3 cases of benign lesions. The most important RCM criteria for diagnosis of AC were cellular atypia at the stratum spinosum and granulosum with atypical honeycomb pattern. One patient with AC was misclassified as inflammatory cheilitis by RCM as it showed marked inflammatory response and lacked clear signs of cellular atypia on RCM imaging. Following topical treatment with diclofenac gel, 5/6 patients (83%) showed a good treatment response with regression of dysplasia on consecutive RCM examination.

CONCLUSIONS

Reflectance confocal microscopy is a promising tool for the non-invasive diagnosis and monitoring of actinic cheilitis. However, marked inflammation represents a potential diagnostic pitfall. In this regard, biopsy should be performed in doubtful cases.

Open label randomized study comparing 3 months vs. 6 months treatment of actinic keratoses with 3% diclofenac in 2.5% hyaluronic acid gel: a trial of the German Dermatologic Cooperative Oncology Group

BACKGROUND

Actinic keratoses (AK) are carcinomata in situ with the potential to develop into invasive carcinoma. Several studies have demonstrated that 3% diclofenac in 2.5% hyaluronic acid gel (HA) is effective and well tolerated in the treatment of AK. To date there are no large randomized multicentre trials with treatment durations longer than 90 days and histopathological control of treatment outcome.

OBJECTIVE

The aim of this study was to investigate whether a prolonged treatment with diclofenac in HA of 6 vs. 3 months adds to the efficacy in treatment for AK and if this will influence tolerability and quality of life (QoL).

METHODS

This was a multicentre, randomized open-label study in which 418 patients with mild to moderate AKs were randomized into two treatment groups. Group A received diclofenac in HA for 3 months and group B for 6 months. Treatment efficacy was assessed by size measurement and a final biopsy of a defined marker AK. Quality of life was measured using the Dermatology Life Quality Index questionnaire.

RESULTS

Clinical complete clearance was observed in 40% in group A and in 45% in group B (P = 0.38). Histopathological clearance was confirmed in 30% in group A and in 40% in group B (P = 0.16). Treatment was well tolerated and QoL was significantly improved after treatment in both treatment groups.

CONCLUSION

Treatment with diclofenac in HA is effective and well tolerated during a treatment period of 3 months as well as 6 months. Prolongation of the treatment duration did not significantly affect treatment outcome.

Efforts to counteract locally the effects of systemic immunosupression: a review on the use of imiquimod, a topical immunostimulator in organ transplant recipients

The potent systemic immunosuppression therapy necessary to sustain a life-saving solid organ transplant is associated with an increased incidence of various infections including human papillomavirus infection and skin cancers in organ transplant recipients. Imiquimod, a topical agent that functions through local induction of a specific anti-viral or anti-tumor immune response, appears to be a promising therapeutic option that could potentially counteract in situ the effects of systemic immunosupression in this vulnerable group. Up-to-date studies using this local immune-response modifier in transplanted patients have yielded reassuring and encouraging results regarding its safety and efficacy in this population. However, in order to establish the use of imiquimod as a standard treatment option for organ transplant recipients, additional research and clinical trials are required.

[Primary and secondary prevention of skin cancer in organ transplant recipients]

Skin cancer constitutes the most frequently reported post-transplant malignancy in solid organ transplant recipients (OTR) worldwide. Whereas the risk for malignant melanoma is only moderately increased, non-melanoma skin cancers (NMSC) seem to thrive on chronic immunosuppression and account for up to 95% of post-transplant cutaneous malignancies. Compared to the general population cutaneous squamous cell carcinoma (SCC) and actinic keratoses (AK) characteristically show even higher incidences than basal cell carcinoma (BCC) and act as an indicator for the development of multiple primary cutaneous neoplasias and locally recurrent cancers (field cancerization). Early diagnosis and therapy of pre-malignant cutaneous lesions is crucial for the secondary prophylaxis of further invasive and highly aggressive skin cancers. High quality interdisciplinary care and prophylactic modalities, including consistent and sufficient UV protection, topical immunmodulatory therapies of UV-damaged skin areas, retinoid chemoprevention as well as tapering immunosuppressive treatment or the selection of immunosuppressants with proposed antiangiogenic properties like mTor-inhibitors may help to reduce the multiplicity of subsequent primary skin cancers in high-risk patients. Apart from the continuous need for educational intervention of OTR in the primary prophylaxis of post-transplant skin cancers, dermatologic care occupies a central position within the field of transplantation medicine in terms of pre- and post-transplantation dermatologic evaluation and therapy as well as the implication of timely and effective secondary preventive approaches in the management of this high-risk patient population.