Topical photodynamic therapy of actinic keratosis in renal transplant recipients

The application of physical pretreatment in photodynamic therapy for skin diseases

Photodynamic therapy (PDT) is widely used in skin diseases; the response rate of PDT treatment varies widely. The limited penetration in the tissue of photosensitizers influenced the penetration depth of PDT, which obviously impacts the therapeutic effect. The studies have improved the efficacy of PDT through various pretreatment applications; especially, the physical pretreatment had achieved significant outcomes. We will review the physical pretreatment to optimize the efficacy of PDT in skin diseases by searching the literature on this topic. The types of physical pretreatment commonly used in the clinical practice are discussed: curettage, superficial shaving, laser, surgical resection, plum-blossom needles, and microneedles. Compared with PDT alone, the physical pretreatment before PDT application was generally improved the efficacy and reduced the recurrence, especially in actinic keratoses (AK), Bowen disease (BD), basal cell carcinoma (BCC), and viral warts. The application of the physical pretreatments before PDT may improve the efficacy of PDT in various skin diseases. However, each kind of physical pretreatment has the benefit and shortcoming, and the applicable situation is different.

Daylight photodynamic therapy for prevention of new actinic keratosis and keratinocyte carcinomas in organ transplants. A cryotherapy-controlled randomized clinical trial

BACKGROUND

Organ transplant recipients (OTR) have a higher risk of actinic keratosis (AK) and keratinocyte carcinomas (KC). There are no clinical trials assessing the effectiveness of daylight photodynamic therapy (DPDT) to prevent new AK and KC in OTR.

OBJECTIVES

To determine whether repeated treatments of field cancerization with DPDT are effective in preventing new AK and KC in OTR.

METHODS

A randomized, intra-subject controlled, evaluator-blind, split-face and/or scalp trial, from April 2016 to October 2018. Participants were OTR older than 18 years, 1-year posttransplant, with at least 5 AK on each hemi-face/hemi-scalp. One side received six field treatments with DPDT: two sessions 15 days apart at baseline, two at 3 months and two at 9 months after baseline. Control side received lesion-directed treatment with cryotherapy (double freeze-thaw) at baseline, 3 and 9 months. Total number of lesions (AK and KC) at 21 months, number of new AK and KC at 3, 9, 15 and 21 months and treatment preferences were analysed.

RESULTS

Of 24 men included, 23 were analysed at 3 months; and 21, at 9, 15 and 21 months. Mean (SD) age was 69.8 years (9.2). The total number of lesions at 21 months was 4.7 (4.3) for DPDT and 5.8 (5.0) for control side; P = 0.09. DPDT showed significantly lower means [SD] of new lesions compared to control side at 3 months (4.2 [3.4] vs. 6.8 [4.8]; P < 0.001), 9 months (3.0 [3.3] vs. 4.3 [3.4]; P = 0.04) and 15 months (3.0 [4.6] vs. 4.8 [5.0]; P = 0.02), and non-significant at 21 months (3.7 [3.5] vs. 5.0 [4.5]; P = 0.06). Most participants preferred DPDT.

CONCLUSION

DPDT showed potential effectiveness in preventing new AK and KC in OTR by consecutive treatments of field cancerization. The preference for DPDT could facilitate adherence to the long-term treatment necessary in these patients.

European Dermatology Forum guidelines on topical photodynamic therapy 2019 Part 2: emerging indications - field cancerization, photorejuvenation and inflammatory/infective dermatoses

In addition to approved indications in non-melanoma skin cancer in immunocompetent patients, topical photodynamic therapy (PDT) has also been studied for its place in the treatment of, as well as its potential to prevent, superficial skin cancers in immune-suppressed patients, although sustained clearance rates are lower than for immune-competent individuals. PDT using a nanoemulsion of ALA in a daylight or conventional PDT protocol has been approved for use in field cancerization, although evidence of the potential of the treatment to prevent new SCC remained limited. High-quality evidence supports a strong recommendation for the use of topical PDT in photorejuvenation as well as for acne, refractory warts, cutaneous leishmaniasis and in onychomycosis, although these indications currently lack approvals for use and protocols remain to be optimized, with more comparative evidence with established therapies required to establish its place in practice. Adverse events across all indications for PDT can be minimized through the use of modified and low-irradiance regimens, with a low risk of contact allergy to photosensitizer prodrugs, and no other significant documented longer-term risks with no current evidence of cumulative toxicity or photocarcinogenic risk. The literature on the pharmacoeconomics for using PDT is also reviewed, although accurate comparisons are difficult to establish in different healthcare settings, comparing hospital/office-based therapies of PDT and surgery with topical ointments, requiring inclusion of number of visits, real-world efficacy as well as considering the value to be placed on cosmetic outcome and patient preference. This guideline, published over two parts, considers all current approved and emerging indications for the use of topical photodynamic therapy in Dermatology prepared by the PDT subgroup of the European Dermatology Forum guidelines committee. It presents consensual expert recommendations reflecting current published evidence.

Photodynamic therapy is more effective than imiquimod for actinic keratosis in organ transplant recipients: a randomized intraindividual controlled trial

BACKGROUND

Actinic keratoses (AKs) in solid organ transplant recipients (OTRs) are difficult-to-treat premalignancies and comparison of topical therapies is therefore warranted.

OBJECTIVES

In an intraindividual study to compare the efficacy and safety of field treatment with methyl aminolaevulinate photodynamic therapy (MAL-PDT) and imiquimod (IMIQ) for AKs in OTRs.

METHODS

OTRs (n = 35) with 572 AKs (grade I-III) in two similar areas on the face, scalp, dorsal hands or forearms were included. All patients received one MAL-PDT and one IMIQ session (three applications per week for 4 weeks) in each study area according to randomization. Treatments were repeated after 2 months (IMIQ) and 3 months (PDT) in skin with incomplete AK response. Outcome measures were complete lesion response (CR), skin reactions, laboratory results and treatment preference.

RESULTS

The majority of study areas received two treatment sessions (PDT n = 25 patients; IMIQ n = 29 patients). At 3 months after two treatments, skin treated with PDT achieved a higher rate of CR (AK I-III median 78%; range 50-100) compared with IMIQ-treated skin areas (median 61%, range 33-100; P < 0·001). Fewer emergent AKs were seen in PDT-treated skin vs. IMIQ-treated skin (0·7 vs. 1·5 AKs, P = 0·04). Patients developed more intense inflammatory skin reactions following PDT, which resolved more rapidly compared with IMIQ (median 10 days vs. 18 days, P < 0·01). Patient preference (P = 0·47) and cosmesis (P > 0·30) were similar for PDT and IMIQ.

CONCLUSIONS

Compared with IMIQ, PDT treatment obtained a higher rate of AK clearance at 3-month follow-up and achieved shorter-lasting, but more intense, short-term skin reactions.

Skin Cancers in Organ Transplant Recipients

Long-term utilization of immunosuppression in organ transplant recipients (OTRs) leads to decreased immune-mediated tumor surveillance and development of malignant tumors. A delicate balance needs to be maintained in the intensity of immunosuppression to keep the risk of malignancy low without jeopardizing life-saving graft function. OTRs are prone to developing skin cancers that exhibit unique epidemiologic, pathophysiologic, and prognostic characteristics. In this review, we discuss the most commonly reported skin cancers in OTRs: squamous cell carcinoma (SCC), basal cell carcinoma (BCC), Kaposi sarcoma, Merkel cell carcinoma, and malignant melanoma (MM). Tumors in this high-risk population are aggressive and may respond poorly to standard therapies; however, new targeted therapies are promising. Checkpoint inhibitor antibodies have been used for treatment of cutaneous SCC, Merkel cell carcinoma, and MM; epidermal growth factor receptor inhibitors have been used for cutaneous SCC; hedgehog pathway inhibitors have been used for BCC; and BRAF and MEK inhibitors are being used increasingly in the management of MM. Guidelines for dermatologic screening are variable and primarily based on expert opinion. Prospective evidence-based trials by multidisciplinary groups are needed to better define surveillance schedules for pre- and posttransplant cutaneous malignancies.

Non-melanoma Skin Cancer in Canada Chapter 3: Management of Actinic Keratoses

Background

Actinic keratosis (AK) and cheilitis (AC) are lesions that develop on photodamaged skin and may progress to form invasive squamous cell carcinomas (SCCs).

Objective

To provide guidance to Canadian health care practitioners regarding management of AKs and ACs.

Methods

Literature searches and development of graded recommendations were carried out as discussed in the accompanying introduction (chapter 1 of the NMSC guidelines).

Results

Treatment of AKs allows for secondary prevention of skin cancer in sun-damaged skin. Because it is impossible to predict whether a given AK will regress, persist, or progress, AKs should ideally be treated. This chapter discusses options for the management of AKs and ACs.

Conclusions

Treatment options include surgical removal, topical treatment, and photodynamic therapy. Combined modalities may be used in case of inadequate response. AKs are particularly common following the longterm immunosuppression in organ transplant patients, who should be monitored frequently to identify emerging lesions that require surgery.

Photodynamic Photorejuvenation: A Review

INTRODUCTION

Topical photodynamic therapy (PDT) is acknowledged to be a safe and efficient therapeutic option for the selective destruction of actinic keratosis and superficial carcinomas. Over the past 15 years, topical PDT has also been shown to be a possible method for "photorejuvenation."

MATERIALS AND METHODS

An extensive review was performed of in vitro and in vivo (animals, organ transplant recipients, or immunocompetent patients) studies.

RESULTS

The studies point to a high level of efficacy. Tone, lentigos, skin roughness, and moreover texture and fine wrinkles because of the effects of dermal remodeling are improved. Adverse effects are generally described as mild to moderate, without scarring, along with a fast recovery time. Patients with fair phototypes and a history of sun exposure and actinic damage of varying severity are the best candidates for this technique. Photodynamic photorejuvenation sessions can both rejuvenate their skins and also treat their visible or incipient UV-induced lesions. New protocols either with daylight use and/or previous intensification by laser or microneedling seem promising.

CONCLUSION

The photodynamic rejuvenation technique seems to show excellent short-term efficacy and tolerability.

Skin changes following organ transplantation: an interdisciplinary challenge

BACKGROUND

The immunosuppressants used in transplantation medicine significantly elevate the incidence of neoplasia, particularly in the skin. The cumulative incidence of non-melanocytic skin cancer (NMSC) in renal transplant recipients was 20.5% in a study carried out in German centers. Data on more than 35 000 renal transplant recipients in the USA document a cumulative NMSC incidence of over 7% after 3 years of immunosuppression.

METHOD

The authors selectively review publications obtained by a PubMed search to discuss the incidence of, and major risk factors for, skin tumors and infectious diseases of the skin in immunosuppressed patients.

RESULTS

The main risk factors for skin tumors are age at the time of transplantation, light skin color, previous and present exposure to sunlight, and the type and duration of immunosuppressive treatment. Squamous-cell carcinoma (SCC) is the most common kind of skin tumor in immunosuppressed patients. Human herpesvirus 8 and Merkel-cell polyoma virus also cause neoplasia more often in immunosuppressed patients than in the general population. Surgical excision is the treatment of choice. Actinic keratosis markedly elevates the risk that SCC will arise in the same skin area (odds ratio 18.36, 95% confidence interval 3.03-111). Patients with multiple actinic keratoses can be treated with photodynamic therapy or with acitretin. To lower the skin cancer risk, organ transplant recipients should apply medical screening agents with a sun protection factor of at least 50 to exposed skin areas every day. 55% to 97% of organ transplant recipients have skin infections; these are treated according to their respective types.

CONCLUSION

Squamous-cell carcinoma of the skin adds to the morbidity and mortality of transplant recipients and is therefore among the major oncological challenges in this patient group. Structured concepts for interdisciplinary care enable risk-adapted treatment.

Update on topical photodynamic therapy for skin cancer

Topical photodynamic therapy has become an established therapy option for superficial non-melanoma skin cancers with a substantial evidence base. In this update the increased choice in photosensitizers and light sources are reviewed as well as novel protocols to move beyond lesional treatment and address field therapy. Daylight PDT is emerging as an alternative to conventional office/hospital-based PDT that offers the advantage of much reduced pain. Although most studies have assessed efficacy of PDT in immune-competent patients, there is accumulating evidence for topical PDT being considered an option to assist in reducing the skin cancer burden in organ transplant recipients. The fluorescence associated with photosensitizer application can help delineate lesions prior to full treatment illumination and offers a useful adjunct to treatment in patients where diagnostic uncertainty or poor lesion outline complicates clinical care. PDT may also offer significant benefit in delaying/preventing new cancer development and combined with its recognized photo-rejuvenating effects, is emerging as an effective therapy capable of clearing certain superficial skin cancers, potentially preventing new lesions as well as facilitating photo-rejuvenating effects in treated areas.

Skin cancer evaluation in transplant patients: a physician opinion survey with recommendations

BACKGROUND

Non-melanoma skin cancer is the most common malignancy in transplant patients. However, routine skin cancer evaluation is currently not the standard of care.

OBJECTIVE

To investigate the current barriers among transplant physicians to skin cancer screening in their patients. To provide recommendations for appropriate routine skin surveillance.

METHODS

A web-based survey was conducted among Baylor, Dallas transplant physicians. Thirty-seven of 46 responses were received, and 13 physicians (28%) were classified as "high screeners."

RESULTS

The univariate analysis revealed three main barriers including the perception of difficulty in seeing a dermatologist (p = 0.017), skin cancer evaluation is not an important aspect of transplant care (p = 0.038), and thirdly, the belief that there is insufficient evidence to warrant universal skin cancer screening in transplant patients (p = 0.013). The fully adjusted multivariable analysis resulted in two significant conclusions; the most important predictor was the perceived lack of medical evidence for skin cancer screening.

LIMITATIONS

The small sample size and all responses being from the same institution in Texas.

CONCLUSION

The dermatologic evidence for regular skin cancer screening in transplant patients needs dissemination to our transplant colleagues. This is a significant practice gap which can be appropriately closed by integrating dermatologists into the transplant team.

Optimal management of skin cancer in immunosuppressed patients

Skin cancer is the most common malignancy in humans with basal cell carcinoma representing the majority of cases in the general population. The prevalence of skin cancer is increased amongst immunosuppressed patients such as those with lymphoproliferative disorders including non-Hodgkin lymphoma and chronic lymphocytic leukemia or those with iatrogenic immunosuppression following organ transplantation. In addition, these patients experience greater morbidity and mortality associated with skin cancers. The most common skin cancer in immunosuppressed patients is squamous cell carcinoma, which often presents with more aggressive features and has a greater rate of metastasis. This article reviews the risk factors, etiology, clinical presentation, and prevalence of skin cancer amongst immunosuppressed patients, including organ transplant, lymphoproliferative disorders, autoimmune disorders, and human immunodeficiency virus. We also provide a comprehensive review of treatment guidelines for immunosuppressed patients with cutaneous malignancy. Surgical therapy is the cornerstone of treatment; however, we also discuss pharmacologic treatment options, lifestyle modifications, and revision of immunosuppressive regimens.

Intensified fractional CO2 laser-assisted photodynamic therapy vs. laser alone for organ transplant recipients with multiple actinic keratoses and wart-like lesions: a randomized half-side comparative trial on dorsal hands

BACKGROUND

Photodynamic therapy (PDT) is a well-documented treatment for actinic keratosis (AK), but achieves inferior efficacy in organ transplant recipients (OTRs), particularly in acral regions. Ablative fractional laser (AFXL) intensifies the PDT response and may improve the efficacy of AK clearance when used as monotherapy.

OBJECTIVES

To compare the efficacy of a single treatment with AFXL-assisted PDT vs. AFXL alone for difficult-to-treat AKs and wart-like lesions (WLLs) in OTRs.

METHODS

Ten OTRs were included with a total of 680 AKs (severity grade I-III) and 409 WLLs on the dorsal hands. Both hands were initially treated with targeted fractional ablation of thick keratotic lesions followed by AFXL field treatment. Treatment regions were then randomized to (i) PDT (AFXL-PDT) or (ii) no further treatment (AFXL). The primary end point was complete response (CR) at 4 months after treatment; secondary end points were improvement of AK severity grade, overall patient assessment of efficacy and tolerability of treatments.

RESULTS

CR of AKs was significantly higher for AFXL-PDT (73%) compared with AFXL alone (31%) (P = 0·002). AFXL-PDT improved 82% of AKs to lower lesion grades compared with 52% after AFXL alone (P = 0.008). For WLLs, the rate of CR was 37% for AFXL-PDT compared with 14% for AFXL (P = 0·02). Overall assessment showed a preference for AFXL-PDT compared with AFXL (AFXL-PDT, n = 8; AFXL, n = 0; equal, n = 2). Mild pigment changes were observed in four patients (AFXL-PDT, n = 3; AFXL, n = 1). No scarring was observed.

CONCLUSIONS

AFXL-PDT is more effective than AFXL in the treatment of acral AKs and WLLs in OTRs.

[New developments in photodynamic therapy]

We review new developments in recent years in photodynamic therapy. Since 2009 two new photosensitizers, a self-adhesive 5-aminolevulinic acid (ALA) patch and a nanoemulsion formulation of 5-aminolevulinic acid have been approved for the treatment of actinic keratoses. Pretreatment with ablative fractional lasers enhances penetration of the photosensitizer and enables intensified PDT in acral lesions and in field-cancerized skin. Several clinical trials have demonstrated the skin-rejuvenating effects of photodynamic therapy, while the underlying mechanisms of action have been clarified. The efficacy of photodynamic therapy has been shown in the treatment and prophylaxis of actinic keratoses in organ transplant recipients at high risk for developing skin cancer. We also summarize the results of available studies on daylight-mediated photodynamic therapy.

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.

Nonmelanoma skin cancer in solid organ transplant recipients: update on epidemiology, risk factors, and management

BACKGROUND

Nonmelanoma skin cancers (NMSC) are the most frequently observed cancers in solid organ transplant recipients (SOTR) and may have a significant disease burden.

OBJECTIVE

To provide an update regarding the epidemiology and management of NMSC in SOTR.

RESULTS

Ten-year incidence rates range from 10% in Italy to 20% in Northern Europe to 70% in Australia. More than 50% of NMSC are located on sun-exposed areas (head, dorsum of hands). Many risk factors have been identified, including age at transplantation, fair skin, type of immunosuppressive drugs, cumulative sun exposure, viral infections, and various genetic markers. Patients with a first NMSC have a 49 times higher risk of developing a subsequent NMSC. Skin self-examination and photoprotection should be encouraged in all transplanted patients. Long-term skin surveillance, early diagnosis and aggressive treatment of any suspicious lesion, reduction of immunosuppressive therapy, and conversion to m-TOR inhibitors can be also effective measures for reduction of NMSC incidence.

CONCLUSIONS

NMSC is the most frequent cancer observed in SOTR. Early diagnosis, patient education, and modification of immunosuppression are effective measures for reduction of NMSC incidence.

Therapeutic options to decrease actinic keratosis and squamous cell carcinoma incidence and progression in solid organ transplant recipients: a practical approach

BACKGROUND

Solid organ transplant recipients (SOTRs) have a 50 to 250 times greater risk of squamous cell carcinoma (SCC) than the general population and experience higher rates of invasive and metastatic disease. These greater risks are a product of the tumorigenic effects of their immunosuppressive medications. As the number of transplantations and the life expectancy of SOTRs increase, SCCs are becoming a major source of morbidity and mortality.

OBJECTIVE

To present a practical approach for busy practicing clinicians to the care of SOTRs who are developing SCCs. Topics include assessment and treatment of new and neglected SOTRs; the dermatologist's role with the transplantation team; and practical considerations in the choice of topical agents, systemic agents, and immunosuppressive therapy manipulation.

METHODS AND MATERIALS

An extensive literature search of the understanding of SCC pathophysiology and treatment in SOTRs was conducted.

RESULTS

Presented here is a logical, concise guide to the care of SOTRs who are developing actinic keratoses and SCCs.

CONCLUSION

Proper assessment of patients, understanding therapeutic alternatives and their application, and early institution of preventative and adjuvant therapies can help to decrease skin cancer-related morbidity and mortality in SOTRs.

Skin cancer in solid organ transplant recipients: advances in therapy and management: part II. Management of skin cancer in solid organ transplant recipients

The management of skin cancer in solid organ transplant recipients is a challenge to both the dermatologist and transplant physician. Part II of this continuing medical education review offers an approach to the management of this increasing problem. The importance of specialty dermatology clinics providing access to transplant patients, frequent skin cancer screening, patient education, and multidisciplinary care is discussed. The management of low risk squamous cell carcinoma with topical therapies, photodynamic therapy, systemic retinoids, and capecitabine is reviewed. Revision of immunosuppression in the management of high-risk patients is discussed in association with the potential role of sentinel lymph node biopsy for aggressive disease. Finally, management of in-transit and metastatic squamous cell carcinoma is reviewed, with a discussion of the role of more recent innovative therapies, including epidermal growth factor receptor inhibitors in advanced squamous cell carcinoma in solid organ transplant recipients.

Oral azathioprine leads to higher incorporation of 6-thioguanine in DNA of skin than liver: the protective role of the Keap1/Nrf2/ARE pathway

Azathioprine is a widely used anti-inflammatory, immunosuppressive, and anticancer agent. However, chronic treatment with this drug is associated with a profoundly increased risk (in certain cases by more than 100-fold) of developing squamous cell carcinoma of the skin. Incorporation of its ultimate metabolite, thio-dGTP, in DNA results in partial substitution of guanine with 6-thioguanine which, combined with exposure to UVA radiation, creates a source of synergistic mutagenic damage to DNA. We now report that oral treatment with azathioprine leads to a much greater incorporation of 6-thioguanine in DNA of mouse skin than liver. These higher levels of 6-thioguanine, together with the fact that the skin is constantly exposed to UV radiation from the sun, may be responsible, at least in part, for the increased susceptibility of this organ to tumor development. Genetic upregulation of the Keap1/Nrf2/ARE pathway, a major cellular regulator of the expression of a network of cytoprotective genes, reduces the incorporation of 6-thioguanine in DNA of both skin and liver following treatment with azathioprine. Similarly, pharmacologic activation of the pathway by the potent inducer sulforaphane results in lower 6-thioguanine incorporation in DNA and protects 6-thioguanine-treated cells against oxidative stress following exposure to UVA radiation. Protection is accompanied by increased levels of glutathione and induction of multidrug resistance-associated protein 4, an organic anion efflux pump that also exports nucleoside monophosphate analogues. Our findings suggest that activation of the Keap1/Nrf2/ARE pathway could reduce the risk for skin cancer in patients receiving long-term azathioprine therapy.

Comparison of protoporphyrin IX accumulation and destruction during methylaminolevulinate photodynamic therapy of skin tumours located at acral and nonacral sites

BACKGROUND

Topical photodynamic therapy (PDT) is successful in the treatment of nonmelanoma skin cancers and associated precancers, but efficacy is significantly reduced in actinic keratosis lesions not located on the face or scalp.

OBJECTIVES

To compare the changes in protoporphyrin IX (PpIX) fluorescence in lesions undergoing routine methylaminolevulinate (MAL) PDT and the clinical outcome observed 3 months after treatment in lesions located at acral and nonacral sites.

METHODS

This study was a noninterventional, nonrandomized, observational study, which monitored changes in PpIX fluorescence in 200 lesions during standard dermatological MAL-PDT. These data were subsequently analysed in terms of lesions located at acral and nonacral sites.

RESULTS

Clinical clearance was significantly reduced (P < 0·01) in acral skin lesions when compared with lesions located at nonacral sites. The accumulation and destruction of PpIX fluorescence was significantly reduced in these acral lesions (P < 0·05 and P < 0·001, respectively). Specifically, lesion location at acral sites significantly reduced changes in PpIX fluorescence in actinic keratosis lesions during MAL-PDT (P < 0·01 and P < 0·05).

CONCLUSIONS

These data suggest that reduced PpIX accumulation and the subsequent reduction in PpIX photobleaching within acral lesions result in the reduced responsiveness of these lesions to MAL-PDT. Future work should therefore aim to improve photosensitizer accumulation/photobleaching within lesions located at acral sites.

Imiquimod 3.75% cream (Zyclara) for the treatment of actinic keratoses

INTRODUCTION

actinic keratosis is a premalignant disease with a high incidence and is a strong predictor for the development of squamous cell carcinoma. Various treatment options have been established over recent years, including topical treatment with imiquimod, 5-fluorouracil, diclofenac or photodynamic therapy, cryotherapy and surgical procedures.

AREAS COVERED

this review covers basic and clinical experiences with imiquimod 3.75% for topical treatment of actinic keratosis of the face and balding scalp and its comparators with special focus on imiquimod 5%. It also covers pharmacology of imiquimod 3.5% and its contribution to the current treatment options of actinic keratoses.

EXPERT OPINION

imiquimod 3.75% is an interesting, safe and well-tolerated treatment option for actinic keratoses of the face or balding scalp especially in respect of compliance, as it is indicated for daily use for a shorter time period (2 times, 2-week cycles) and approved for use on larger areas compared with imiquimod 5%. Data from current trials indicate lower efficacy compared with imiquimod 5% cream when applied three times a week for 16 weeks or for two 4-week cycles with a 4-week no-treatment interval, but indicate similar efficacy when compared with a twice-weekly schedule for 16 weeks. An additive effect was observed when combining cryosurgery followed by imiquimod 3.75%.

Combination of photodynamic therapy and immunomodulation for skin diseases--update of clinical aspects

In dermatology, photodynamic therapy (PDT) has become a well established treatment modality which has been shown to be effective and safe for many skin and mucosal disorders. Pre-clinical and clinical studies demonstrate that, in addition to the direct local cytotoxicity and vascular effects, PDT can induce various host immune responses. Recent clinical data also show that improved clinical outcomes can be obtained through the sequential use of PDT and immunomodulation. This article will provide an update on the current status of such a combination in dermatological applications.

An overview of topical photodynamic therapy in dermatology

This article is a review of the use of topical photodynamic therapy in dermatology and its current role in 2009 and future developments. The content of this article was presented at the EPPM in Wroclaw, September 2009.