A randomized pilot comparative study of topical methyl aminolevulinate photodynamic therapy versus imiquimod 5% versus sequential application of both therapies in immunocompetent patients with actinic keratosis: clinical and histologic outcomes

Pre-treatment with topical 5-fluorouracil increases the efficacy of daylight photodynamic therapy for actinic keratoses - A randomized controlled trial

BACKGROUND

Daylight photodynamic therapy (dPDT) and topical 5-fluorouracil (5-FU) are each effective treatments for thin grade I actinic keratosis (AKs), but less so for thicker grade II-III AKs. Prolonged topical treatment regimens can be associated with severe skin reactions and low compliance. This study compares the efficacy of sequential 4 % 5-FU and dPDT with dPDT monotherapy for multiple actinic keratoses.

METHODS

Sixty patients with a total of 1547 AKs (grade I: 1278; grade II: 246; grade III: 23) were treated in two symmetrical areas (mean size 75 cm2) of the face or scalp, which were randomized to (i) 4% 5-FU creme twice daily for 7 days before a single dPDT procedure and (ii) dPDT monotherapy. Daylight exposure was either outdoor or indoor daylight.

RESULTS

Twelve weeks after treatment 87 % of all AKs cleared after 5-FU+dPDT compared to 74 % after dPDT alone (p<0.0001). For grade II AKs, the lesion response rate increased from 55 % with dPDT monotherapy to 79 % after 5-FU+dPDT (p<0.0056). Moderate/severe erythema was seen in 88 % 5-FU+dPDT areas compared to 41 % of dPDT areas two days after dPDT. Twelve weeks after treatment 75 % of the patients were very satisfied with both treatments.

CONCLUSIONS

Sequential 5-FU and dPDT was more effective than dPDT monotherapy in the treatment of AKs, especially for grade II AKs. Local skin reactions were more pronounced after combination treatment, but no patients discontinued the treatment. The combination of 5-FU and dPDT is an effective treatment of large treatment areas with high compliance and satisfaction.

Treatment of nonmelanoma skin cancer with pro-differentiation agents and photodynamic therapy: Preclinical and clinical studies (Review)

Photodynamic therapy (PDT) is a nonscarring cancer treatment in which a pro-drug (5-aminolevulinic acid, ALA) is applied, converted into a photosensitizer (protoporphyrin IX, PpIX) which is then activated by visible light. ALA-PDT is now popular for treating nonmelanoma skin cancer (NMSC), but can be ineffective for larger skin tumors, mainly due to inadequate production of PpIX. Work over the past two decades has shown that differentiation-promoting agents, including methotrexate (MTX), 5-fluorouracil (5FU) and vitamin D (Vit D) can be combined with ALA-PDT as neoadjuvants to promote tumor-specific accumulation of PpIX, enhance tumor-selective cell death, and improve therapeutic outcome. In this review, we provide a historical perspective of how the combinations of differentiation-promoting agents with PDT (cPDT) evolved, including Initial discoveries, biochemical and molecular mechanisms, and clinical translation for the treatment of NMSCs. For added context, we also compare the differentiation-promoting neoadjuvants with some other clinical PDT combinations such as surgery, laser ablation, iron-chelating agents (CP94), and immunomodulators that do not induce differentiation. Although this review focuses mainly on the application of cPDT for NMSCs, the concepts and findings described here may be more broadly applicable towards improving the therapeutic outcomes of PDT treatment for other types of cancers.

Evaluating the Efficacy and Safety of 4% 5-Fluorouracil Cream in Patients with Actinic Keratosis: An Expert Opinion

Actinic keratosis is a lesion that develops in sun-exposed areas of the skin and is considered to be a precancerous condition or an early in situ squamous cell carcinoma. Treatment of actinic keratosis is important for reducing skin cancer risk, with treatment choice based on patient-, lesion- and treatment-related considerations. Of the topical treatments used for field-directed therapy, those containing 5-fluorouracil are among the most effective and widely prescribed. The most recently developed topical 5-fluorouracil preparation (Tolak®; Pierre Fabre, France) contains 4% 5-fluorouracil in an aqueous cream. This narrative review discusses data on 4% 5-fluorouracil cream to treat actinic keratosis, and provides the authors' expert opinion on issues associated with it use. The effect of the cream has been evaluated in phase 2 and 3 trials of adult patients with actinic keratosis on the face, ears or scalp. These trials included patients with severe baseline disease, defined by high lesion counts and large-size treatment fields, which possibly affected the proportion of patients who were able to achieve complete clearance. Other efficacy parameters (e.g. percentage change in lesion count, ≥ 75% clearance of lesions or clinically significant changes in validated severity scales) should also be assessed to fully evaluate 4% 5-fluorouracil treatment efficacy in these patients. Nevertheless, 4% 5-fluorouracil is associated with high efficacy, a low level of recurrence and a satisfactory safety profile.

A Review of MAL-PDT for the Treatment Strategy of Actinic Keratosis: Broader Clinical Perspectives Beyond the Data and Guideline Recommendations

Methyl aminolevulinate (MAL) is a topical compound approved for use with photodynamic therapy (PDT) for the treatment of actinic keratosis (AK) and field cancerization in certain countries. There exists a high burden of disease for patients with AK: repeated treatments are required, there is a known risk of progression to keratinocyte carcinoma, and cosmetic appearance is affected. Delivery of PDT using MAL is a flexible treatment strategy available in many forms; red light, daylight, or artificial daylight can be used for illumination, all of which result in high AK clearance rates and low recurrence. MAL-PDT protocols continue to evolve to further improve adherence and treatment outcomes. Here, we used PubMed to search MEDLINE to identify guidelines, consensus recommendations, and studies describing the use of MAL for the treatment of AK. The aim of this targeted review is to consider various MAL-PDT treatment strategies on the basis of published literature, with a focus on personalizing treatment for the heterogeneous AK population.

Efficacy and Safety of Photodynamic Therapy for the Treatment of Actinic Keratoses: A Meta-Analysis Update of Randomized Controlled Trials

BACKGROUND

Actinic keratoses (AKs) are common and some may evolve into squamous cell carcinoma. Photodynamic therapy (PDT), imiquimod, cryotherapy, and other methods have been reported to have good effects. However, which treatment is the most effective with the best cosmetic results and fewest complications is uncertain.

OBJECTIVE

To evaluate which method has the best efficacy and cosmetic results with less adverse events and recurrence rate.

MATERIALS AND METHODS

All relevant articles up to July 31, 2022 were searched from Cochrane, Embase, and PubMed databases. Extract and analyze the data of efficacy, cosmetic results, local reactions, and adverse effects.

RESULTS

Twenty-nine articles with 3,,850 participants and 24,747 lesions were included. Quality of evidence was generally high. The efficacy of PDT was better in complete response (CR) (lesions CR; risk ratio (RR) 1.87; 95% confidence interval (CI) 1.55-1.87/patient CR; RR 3.07; 95% CI 2.07-4.56), overall preference, and cosmetic results. The time cumulative meta-analysis showed that the curative effect was gradually increasing before 2004, and then gradually stabilizing. Two groups showed no statistically significant differences in recurrence.

CONCLUSION

Compared with other methods, PDT is significantly more effective for AK with excellent cosmetic results and reversible adverse effects.

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.

Combination-Based Strategies for the Treatment of Actinic Keratoses with Photodynamic Therapy: An Evidence-Based Review

Photodynamic therapy (PDT) is a highly effective and widely adopted treatment strategy for many skin diseases, particularly for multiple actinic keratoses (AKs). However, PDT is ineffective in some cases, especially if AKs occur in the acral part of the body. Several methods to improve the efficacy of PDT without significantly increasing the risks of side effects have been proposed. In this study, we reviewed the combination-based PDT treatments described in the literature for treating AKs; both post-treatment and pretreatment were considered including topical (i.e., diclofenac, imiquimod, adapalene, 5-fluorouracil, and calcitriol), systemic (i.e., acitretin, methotrexate, and polypodium leucotomos), and mechanical–physical (i.e., radiofrequency, thermomechanical fractional injury, microneedling, microdermabrasion, and laser) treatment strategies. Topical pretreatments with imiquimod, adapalene, 5-fluorouracil, and calcipotriol were more successful than PDT alone in treating AKs, while the effect of diclofenac gel was less clear. Both mechanical laser treatment with CO2 and Er:YAG (Erbium:Yttrium–Aluminum–Garnet) as well as systemic treatment with Polypodium leucotomos were also effective. Different approaches were relatively more effective in particular situations such as in immunosuppressed patients, AKs in the extremities, or thicker AKs. Conclusions: Several studies showed that a combination-based approach enhanced the effectiveness of PDT. However, more studies are needed to further understand the effectiveness of combination therapy in clinical practice and to investigate the role of acitretin, methotrexate, vitamin D, thermomechanical fractional injury, and microdermabrasion in humans.

Advances in Photodynamic Therapy Based on Nanotechnology and Its Application in Skin Cancer

Comprehensive cancer treatments have been widely studied. Traditional treatment methods (e.g., radiotherapy, chemotherapy), despite ablating tumors, inevitably damage normal cells and cause serious complications. Photodynamic therapy (PDT), with its low rate of trauma, accurate targeting, synergism, repeatability, has displayed great advantages in the treatment of tumors. In recent years, nanotech-based PDT has provided a new modality for cancer treatment. Direct modification of PSs by nanotechnology or the delivery of PSs by nanocarriers can improve their targeting, specificity, and PDT efficacy for tumors. In this review, we strive to provide the reader with a comprehensive overview, on various aspects of the types, characteristics, and research progress of photosensitizers and nanomaterials used in PDT. And the application progress and relative limitations of nanotech-PDT in non-melanoma skin cancer and melanoma are also summarized.

Comparative Efficacy and Safety of Tirbanibulin for Actinic Keratosis of the Face and Scalp in Europe: A Systematic Review and Network Meta-Analysis of Randomized Controlled Trials

Actinic keratosis (AK) is a chronic skin condition that may progress to cutaneous squamous cell carcinoma. We conducted a systematic review of efficacy and safety for key treatments for AK of the face and scalp, including the novel 5-day tirbanibulin 1% ointment. MEDLINE, PubMed, Embase, Cochrane Library, clinical trial registries and regulatory body websites were searched. The review included 46 studies, of which 35 studies included interventions commonly used in Europe and were sufficiently homogenous to inform a Bayesian network meta-analysis of complete clearance against topical placebo or vehicle. The network meta-analysis revealed the following odds ratios and 95% credible intervals: cryosurgery 13.4 (6.2–30.3); diclofenac 3% 2.9 (1.9–4.3); fluorouracil 0.5% + salicylic acid 7.6 (4.6–13.5); fluorouracil 4% 30.3 (9.1–144.7); fluorouracil 5% 35.0 (10.2–164.4); imiquimod 3.75% 8.5 (3.5–22.4); imiquimod 5% 17.9 (9.1–36.6); ingenol mebutate 0.015% 12.5 (8.1–19.9); photodynamic therapy with aminolevulinic acid 24.1 (10.9–52.8); photodynamic therapy with methyl aminolevulinate 11.7 (6.0–21.9); tirbanibulin 1% 11.1 (6.2–20.9). Four sensitivity analyses, from studies assessing efficacy after one treatment cycle only, for ≤25 cm² treatment area, after 8 weeks post-treatment, and with single placebo/vehicle node confirmed the findings from the base case. Safety outcomes were assessed qualitatively. These results suggest that tirbanibulin 1% offers a novel treatment for AK, with a single short treatment period, favourable safety profile and efficacy, in line with existing topical treatments available in Europe.

Sequential Treatment of Superficial Basal Cell Carcinomas With Topical Methyl Aminolevulinate Photodynamic Therapy and Imiquimod 5% Cream: A Retrospective Study of Clinical and Cosmetic Outcomes

BACKGROUND

Topical photodynamic therapy (PDT) and imiquimod 5% (IMQ) cream are established treatments for superficial basal cell carcinoma (sBCC). Both have high initial response rates and recurrence rates of up to 37%. Recent studies demonstrate that PDT and imiquimod may act on sBCCs via synergistic immunomodulatory pathways.

OBJECTIVE

To describe the sequential use of MAL-PDT and imiquimod 5% cream in the treatment of sBCCs and report treatment tolerability, cosmetic outcomes, and efficacy.

MATERIALS AND METHODS

This is a retrospective case series of patients presenting over a 2-year period with primary sBCC who underwent 2 cycles of topical MAL-PDT, followed by 6 weeks of imiquimod 5% cream. Outcome measures were resolution of the index lesion at 3 months, side effects, cosmetic outcome, and long-term recurrence (LTR).

RESULTS

A total of 17 consecutive patients (n = 17) with a combined 21 sBCCs (n = 21) were included. The median length of follow-up was 72 months (range 24-95 months). Long-term recurrence occurred in 2/21 lesions (10%).

CONCLUSION

Sequential use of PDT and imiquimod was well tolerated with good cosmetic outcomes. The 10% LTR rate is at the lower end of the range reported for single modality treatment; however, larger samples are required to evaluate efficacy differences.

Toll-like receptor signalling in B cells during systemic lupus erythematosus

B lymphocytes have a central role in autoimmune diseases, which are often defined by specific autoantibody patterns and feature a loss of B cell tolerance. A prototypic disease associated with B cell hyperactivity is systemic lupus erythematosus (SLE). In patients with SLE, the loss of B cell tolerance to autoantigens is controlled in a cell-intrinsic manner by Toll-like receptors (TLRs), which sense nucleic acids in endosomes. TLR7 drives the extrafollicular B cell response and the germinal centre reaction that are involved in autoantibody production and disease pathogenesis. Surprisingly, TLR9 seems to protect against SLE, even though it is required for the production of autoantibodies recognizing double-stranded DNA-associated antigens, which are abundant in SLE and are a hallmark of this disease. The protective function of TLR9 is at least partly mediated by its capacity to limit the stimulatory activity of TLR7. The roles of TLR7 and TLR9 in the effector function of B cells in lupus-like disease and in patients with SLE, and the unique features of TLR signalling in B cells, suggest that targeting TLR signalling in SLE might be therapeutically beneficial.

Loss of B cell tolerance to autoantigens in systemic lupus erythematosus (SLE) is driven by TLR7, whereas TLR9 appears to protect against SLE by limiting the stimulatory activity of TLR7. The unique features of Toll-like receptor signalling in B cells implicate it as a therapeutic target in SLE.

Intrinsic TLR7 and TLR9 signalling in B cells plays an important role in the development and pathogenesis of systemic lupus erythematosus (SLE).

In patients with SLE, effector plasma cells are generated via the extrafollicular response and via the formation of spontaneous germinal centres.

TLR7 plays key roles in the extrafollicular response and the response mediated by germinal centres.

Some plasma cells produce IL-10 and can have protective roles in lupus-like disease.

Sequential daylight photodynamic therapy and ingenol mebutate versus 2 sessions of daylight photodynamic therapy for the treatment of actinic keratosis: An observational, prospective, comparative study

BACKGROUND

Field-directed therapy, such as daylight-photodynamic therapy (DL-PDT) or ingenol mebutate (IM), is indicated for multiple actinic keratosis (AK) lesions located on contiguous areas of skin with significant sun damage.

OBJECTIVE

To compare the efficacy of sequential DL-PDT and IM treatment with that of 2 sessions of DL-PDT in AK patients.

MATERIAL AND METHODS

For this observational, multicenter, prospective study we recruited patients for whom DL-PDT was indicated for the treatment of AK lesions (grades I and II) located on the head. After 1 month of follow-up those who did not achieve a satisfactory clinical response received either a second session of DL-PDT or were treated with IM. Epidemiological and clinical data were collected and analyzed.

RESULTS

Forty-three patients were enrolled (39 male, 4 female). The mean (standard deviation, SD) age was 78 (7.84) years, and the mean (SD) number of AK lesions per patient was 9.58 (1.16). After the first session of DL-PDT, 27 patients (62.8%) required further treatment: 13 (48.1%) received a second session of DL-PDT and 14 (51.9%) were treated with IM. After 1 year of follow-up, lesion clearance rates were higher in patients who received 2 sessions of DL-PDT than those treated with sequential DL-PDT plus IM (75.2%vs 54.6%, p = 0.0013). Local skin reactions were more frequent in the DL-PDT plus IM group than the group treated with 2 sessions of DL-PDT (p = 0.0245).

CONCLUSIONS

The combination of DL-PDT plus IM appears to have no synergistic effect in the treatment of field cancerization, and offers no benefits over 2 sessions of DL-PDT monotherapy, although both combinations produced high lesion clearance rates, a good safety profile, excellent cosmetic outcome, and good patient satisfaction.

Current developments in pharmacotherapy for actinic keratosis

INTRODUCTION

Actinic keratosis (AK) is a superficial squamous cell carcinoma (SCC) where chronic sun exposure playing central role in its pathogenesis. UVB causes direct damage to DNA, producing pyrimidine dimers, and suppressing the protective role of p53. The stepwise progression of AK, with increased expression of anti-apoptotic Bcl-2, favors progression to SCC. Moreover, the dermal response characterized by inflammation and mediated by prostaglandins is a critical component of tumorigenesis that promotes tumor growth, tissue invasion, angiogenesis and metastasis. Other risk factors are represented by age, gender, phototype and drugs.

AREAS COVERED

In this review, the authors document the recent developments of different therapies used to treat AK and provide their perspectives on current and future treatment strategies.

EXPERT OPINION

The usefulness of long-term treatment with piroxicam and sun filters or diclofenac targeting the inflammation phases of skin tumorigenesis favors AK's healing and provides greater control of the cancerization field. Nonsteroidal anti-inflammatory drugs can be safely used in patients who use photosensitizing drugs and, therefore, are more at risk of developing skin tumors. Immunomodulatory therapies, which require shorter treatment, are characterized by more common local side effects, and need more attention by the dermatologist in the concern of patient education, resulting essential to improve adherence and outcomes.

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.

Daylight-Mediated Photodynamic Therapy With Methyl Aminolevulinate in Actinic Keratosis Treatment

BACKGROUND

Research has shown daylight-mediated photodynamic therapy (PDT) for the treatment of actinic keratosis (AK) to be effective, tolerable, and convenient, with excellent patient satisfaction and cosmesis. Although success has been demonstrated in areas with similar latitudes to Switzerland and Scandinavia, this treatment has not been studied in a Canadian population.

OBJECTIVES

The purpose of this study is to investigate the effectiveness, safety, and patient satisfaction of daylight-mediated methyl 5-aminolevulinate (MAL)-PDT to make recommendations for its use in Canadian practice.

METHODS

A retrospective chart review of patients who received treatment of daylight-mediated MAL-PDT for the indication of AK at the Institute of Cosmetic and Laser Surgery in Oakville, Ontario, between 2009 and 2016.

RESULTS

A total of 112 patients were included, consisting of 94 males and 18 females with a mean age of 63.79 years. A total of 177 sites were treated among all patients, mostly consisting of the face (n = 92) and scalp (n = 55). A total of 13.4% of patients experienced side effects, the most common being redness (n = 4) and scabbing (n = 4). Of the 42 patients who expressed their level of satisfaction, 83.3% reported being happy with the treatment, χ²(1) = 18.67, P ≤ .05; 6.3% of patients were noted to be completely clear, 86.6% had a good response, 0.9% had a mild response, and 0% had no response, χ²(1) = 101.04, P ≤ .05.

CONCLUSIONS

Daylight-mediated MAL-PDT is a suitable treatment option for AK lesions in a Canadian population due to the demonstrated efficacy, patient satisfaction, tolerability, and convenience.

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.

Immunomodulatory and antitumor effects of type I interferons and their application in cancer therapy

During the last decades, the pleiotropic antitumor functions exerted by type I interferons (IFNs) have become universally acknowledged, especially their role in mediating interactions between the tumor and the immune system. Indeed, type I IFNs are now appreciated as a critical component of dendritic cell (DC) driven T cell responses to cancer. Here we focus on IFN-α and IFN-β, and their antitumor effects, impact on immune responses and their use as therapeutic agents. IFN-α/β share many properties, including activation of the JAK-STAT signaling pathway and induction of a variety of cellular phenotypes. For example, type I IFNs drive not only the high maturation status of DCs, but also have a direct impact in cytotoxic T lymphocytes, NK cell activation, induction of tumor cell death and inhibition of angiogenesis. A variety of stimuli, including some standard cancer treatments, promote the expression of endogenous IFN-α/β, which then participates as a fundamental component of immunogenic cell death. Systemic treatment with recombinant protein has been used for the treatment of melanoma. The induction of endogenous IFN-α/β has been tested, including stimulation through pattern recognition receptors. Gene therapies involving IFN-α/β have also been described. Thus, harnessing type I IFNs as an effective tool for cancer therapy continues to be studied.

Transcutaneous immunization with a novel imiquimod nanoemulsion induces superior T cell responses and virus protection

BACKGROUND

Transcutaneous immunization (TCI) is a novel vaccination strategy utilizing the skin associated lymphatic tissue to induce immune responses. TCI using a cytotoxic T lymphocyte (CTL) epitope and the Toll-like receptor 7 (TLR7) agonist imiquimod mounts strong CTL responses by activation and maturation of skin-derived dendritic cells (DCs) and their migration to lymph nodes. However, TCI based on the commercial formulation Aldara only induces transient CTL responses that needs further improvement for the induction of durable therapeutic immune responses.

OBJECTIVE

Therefore we aimed to develop a novel imiquimod solid nanoemulsion (IMI-Sol) for TCI with superior vaccination properties suited to induce high quality T cell responses for enhanced protection against infections.

METHODS

TCI was performed by applying a MHC class I or II restricted epitope along with IMI-Sol or Aldara (each containing 5% Imiquimod) on the shaved dorsum of C57BL/6, IL-1R, Myd88, Tlr7 or Ccr7 deficient mice. T cell responses as well as DC migration upon TCI were subsequently analyzed by flow cytometry. To determine in vivo efficacy of TCI induced immune responses, CTL responses and frequency of peptide specific T cells were evaluated on day 8 or 35 post vaccination and protection in a lymphocytic choriomeningitis virus (LCMV) infection model was assessed.

RESULTS

TCI with the imiquimod formulation IMI-Sol displayed equal skin penetration of imiquimod compared to Aldara, but elicited superior CD8⁺ as well as CD4⁺ T cell responses. The induction of T-cell responses induced by IMI-Sol TCI was dependent on the TLR7/MyD88 pathway and independent of IL-1R. IMI-Sol TCI activated skin-derived DCs in skin-draining lymph nodes more efficiently compared to Aldara leading to enhanced protection in a LCMV infection model.

CONCLUSION

Our data demonstrate that IMI-Sol TCI can overcome current limitations of previous imiquimod based TCI approaches opening new perspectives for transcutaneous vaccination strategies and allowing the use of this enhanced cutaneous drug-delivery system to be tailored for the improved prevention and treatment of infectious diseases and cancers.

Photodynamic Therapy and Non-Melanoma Skin Cancer

Non-melanoma skin cancer (NMSC) is the most common malignancy among the Caucasian population. Photodynamic therapy (PDT) is gaining popularity for the treatment of basal cell carcinoma (BCC), Bowen's disease (BD) and actinic keratosis (AK). A topical or systemic exogenous photosensitiser, results in selective uptake by malignant cells. Protoporphyrin IX (PpIX) is produced then activated by the introduction of a light source. Daylight-mediated MAL (methyl aminolaevulinate) PDT for AKs has the advantage of decreased pain and better patient tolerance. PDT is an effective treatment for superficial BCC, BD and both individual and field treatment of AKs. Excellent cosmesis can be achieved with high patient satisfaction. Variable results have been reported for nodular BCC, with improved outcomes following pretreatment and repeated PDT cycles. The more aggressive basisquamous, morphoeic infiltrating subtypes of BCC and invasive squamous cell carcinoma (SCC) are not suitable for PDT. Prevention of "field cancerization" in organ transplant recipients on long-term immunosuppression and patients with Gorlin syndrome (naevoid basal cell carcinoma syndrome) is a promising development. The optimisation of PDT techniques with improved photosensitiser delivery to target tissues, new generation photosensitisers and novel light sources may expand the future role of PDT in NMSC management.

Precancerous Skin Lesions

Certain clinically and histologically recognizable skin lesions with a degree of risk of progression to squamous cell carcinoma have been traditionally grouped as precancerous skin conditions but now tend to be classified as in situ carcinomas. This consensus statement discusses various aspects of these lesions: their evaluation by means of clinical and histopathologic features, the initial evaluation of the patient, the identification of risk factors for progression, and the diagnostic and treatment strategies available today.

Sequential Curettage, 5-Fluorouracil, and Photodynamic Therapy for Field Cancerization of the Scalp and Face in Solid Organ Transplant Recipients

BACKGROUND

Field cancerization with actinic keratoses and squamous cell carcinoma in situ (AK/SCCIS) represents a common therapeutic challenge in solid organ transplant recipients (SOTRs). These patients often show inadequate responses to methods traditionally used as monotherapy (e.g., topical chemotherapy).

OBJECTIVE

To describe the clinical outcomes and feasibility of a sequential approach to treatment of field cancerization in SOTRs.

METHODS

Four SOTRs with field cancerization of the scalp and/or face were treated using a sequential approach. Light curettage of hypertrophic lesions was followed by application of 5-fluorouracil 5% cream twice daily for 5 days and photodynamic therapy (PDT) with 1-hour incubation on day 6. Pain level during and after PDT was recorded. Photographs were obtained immediately before and after treatment and at follow-up appointments.

RESULTS

All 4 patients tolerated this approach well and demonstrated excellent responses to treatment with complete or near-complete clinical resolution of AK/SCCIS lesions. Patients remained free of AK/SCCIS based on clinical examination 1 to 6 months after treatment.

CONCLUSION

For SOTRs with field cancerization, sequential therapy represents a viable therapeutic regimen with good tolerability and durable clinical response. This approach warrants further investigation to determine which therapeutic combinations have optimal tolerability and efficacy.

Three-Dimensional Rejuvenation of the Décolletage

BACKGROUND

Photodamaged skin of the chest is characterized by skin laxity, lines/wrinkles, hyperpigmentation, erythema, tactile roughness, atrophy, and telangiectasias.

METHODS

A MEDLINE search was performed on combination treatments in chest rejuvenation, and the results are summarized. Practical applications for these combinations of procedures are discussed.

RESULTS

Reports of injectable poly-L-lactic acid (PLLA), hyaluronic acid (HA), and chemical peels, along with lasers and light therapies such as intense pulsed light (IPL), vascular lasers, photodynamic therapy (PDT), nonablative fractionated lasers (NAFLs), ablative fractionated lasers (AFLs), and microfocused ultrasound (MFU) have been reported for chest rejuvenation. Few articles were discovered pertaining to combination therapy. The authors review their approaches to combination therapy.

CONCLUSION

Multiple options exist alone or in combination for minimally invasive rejuvenation of the skin of the chest including PLLA, HA, chemical peels, IPL, vascular lasers, PDT, NAFL, AFL, and MFU. Little was found in the literature pertaining to the safety and efficacy of combining such procedures and devices. The authors' experience in clinical practice is that combination, same day chest rejuvenation techniques can be performed safely. A combination approach often produces the most optimal outcome for the patient seeking chest rejuvenation.

Skin tumor development after UV irradiation and photodynamic therapy is unaffected by short-term pretreatment with 5-fluorouracil, imiquimod and calcipotriol. An experimental hairless mouse study

BACKGROUND

Photodynamic therapy (PDT) delays ultraviolet (UV) radiation-induced squamous cell carcinomas (SCCs) in hairless mice. Efficacy may be enhanced by combining PDT with antineoplastic or pro-differentiating agents. We investigated if pretreatment with 5-fluorouracil (5FU), imiquimod (IMIQ) or calcipotriol (CAL) before PDT further delays tumor onset.

METHODS

Hairless mice (n=224) were exposed 3 times weekly to 3 standard erythema doses (SED) of UV radiation. Methyl-aminolevulinate (MAL)-PDT sessions were given on days 45 and 90 before SCC development. Three applications of topical 5FU, IMIQ or CAL were given before each PDT session. Fluorescence photography quantified protoporphyrin IX (PpIX) formation.

RESULTS

PDT delayed UV-induced SCC development by 59 days (212 days UV-MAL-PDT vs. 153 days UV-control, P<0.001). Pretreatment with 5FU, IMIQ or CAL before PDT did not further delay SCC onset compared to PDT alone (207 days UV-5FU-MAL-PDT, 215 days UV-IMIQ-MAL-PDT, 206 days UV-CAL-MAL-PDT vs. 212 days UV-MAL-PDT, P=ns). PpIX fluorescence intensified by 5FU-pretreatment (median 21,392 au UV-5FU-MAL-PDT, P=0.011), decreased after IMIQ-pretreatment (12,452 au UV-IMIQ-MAL-PDT, P<0.001), and was unaffected by CAL-pretreatment (19,567 au UV-CAL-MAL-PDT, P=ns) compared to MAL alone (18,083 au UV-MAL-PDT).

CONCLUSIONS

Short-term three-day pretreatment with 5FU, IMIQ and CAL before PDT does not further delay tumor onset in UV-exposed hairless mice.

Combined Treatments with Photodynamic Therapy for Non-Melanoma Skin Cancer

Non-melanoma skin cancer (NMSC) is the most common form of cancer in the Caucasian population. Among NMSC types, basal cell carcinoma (BCC) has the highest incidence and squamous cell carcinoma (SCC) is less common although it can metastasize, accounting for the majority of NMSC-related deaths. Treatment options for NMSC include both surgical and non-surgical modalities. Even though surgical approaches are most commonly used to treat these lesions, Photodynamic Therapy (PDT) has the advantage of being a non-invasive option, and capable of field treatment, providing optimum cosmetic outcomes. Numerous clinical research studies have shown the efficacy of PDT for treating pre-malignant and malignant NMSC. However, resistant or recurrent tumors appear and sometimes become more aggressive. In this sense, the enhancement of PDT effectiveness by combining it with other therapeutic modalities has become an interesting field in NMSC research. Depending on the characteristics and the type of tumor, PDT can be applied in combination with immunomodulatory (Imiquimod) and chemotherapeutic (5-fluorouracil, methotrexate, diclofenac, or ingenol mebutate) agents, inhibitors of some molecules implicated in the carcinogenic process (COX2 or MAPK), surgical techniques, or even radiotherapy. These new strategies open the way to a wider improvement of the prevention and eradication of skin cancer.

How to treat actinic keratosis? An update

Actinic keratosis (AKs) is one of the most common skin lesions leading to an increased risk of developing squamous cell carcinoma and other skin malignancies. The lesions principally arise as a result of excessive ultraviolet (UV) exposure. AKs may regress spontaneously, remain stable or evolve to invasive squamous cell carcinoma. The risk of squamous cell carcinoma is significantly increased patients with more than 5 AKs. The main mechanisms involved in the formation of AK are inflammation, mutagenesis, oxidative stress, impaired apoptosis, immunosuppression, disregulation of cell growth and proliferation, and tissue remodeling. Human papilloma virus has also been correlated with the formation of some AKs. As an individual ages, his skin is exposed to increasing cumulative amounts of UV light and other environmental insults. This is especially true for the head, neck and forearms. These insults do not target only the skin where individual lesions develop, but also the surrounding area. In this area undetectable preclinical AK lesions or dysplastic cells may be present. The whole affected area is known as the 'field'. Therefore, management is divided into lesion-directed and field-directed therapies. Currently, the therapies in use are lesion-directed cryotherapy and/or excision, and field-directed topical agents: 5-fluorouracil, diclofenac, photodynamic therapy, imiquimod, and ingenol mebutate. Combining lesion- and field-directed therapies showed good results and several novel therapies are under investigation. Treatment is variable and personalized, what makes a gold standard management algorithm difficult to design. This review aims to describe the rationale behind the available treatment options for AKs based on current understanding of pathophysiology and epidemiology.

Dual roles of TLR7 in the lung cancer microenvironment

Toll-like receptor 7 (TLR7) agonists are under investigation for their ability to enhance antitumor immune responses. However, these agonists can also stimulate TLR7-expressing tumor cells. High TLR7 expression in the primary tumor confers poor clinical outcome and resistance to chemotherapy in lung cancer patients. This protumorigenic effect of TLR7 has been validated in murine models of lung carcinoma.

Actinic keratoses - a systemic review

Mainly elderly people with pale skin are affected by actinic keratoses (AK). Due to the demographic change, the prevalence of AK increased over the last years. An established risk factor is chronic UV-exposure (outdoor workers) inducing mutations of the tumor suppressor gene TP53 and the oncogene H-Ras. This leads to an intraepidermal proliferation of atypical keratinocytes. The term “field cancerization” characterises the presentation of multiple AK in UV-exposed areas. AK are also termed squamous cell carcinoma (SCC) in situ. The risk for AK turning into a SCC is 6-10%. In order to avoid invasive growth, an early treatment is recommended. During the last years multiple therapeutic options have been established. Depending on the clinical extent, lesion- or field-directed therapies with excellent clinical response and cosmetic results are available.

Current evidence and applications of photodynamic therapy in dermatology

In photodynamic therapy (PDT) a photosensitizer – a molecule that is activated by light – is administered and exposed to a light source. This leads both to destruction of cells targeted by the particular type of photosensitizer, and immunomodulation. Given the ease with which photosensitizers and light can be delivered to the skin, it should come as no surprise that PDT is an increasingly utilized therapeutic in dermatology. PDT is used commonly to treat precancerous cells, sun-damaged skin, and acne. It has reportedly also been used to treat other conditions including inflammatory disorders and cutaneous infections. This review discusses the principles behind how PDT is used in dermatology, as well as evidence for current applications of PDT.

Photodynamic therapy vs. imiquimod 5% cream as skin cancer preventive strategies in patients with field changes: a randomized intraindividual comparison study

BACKGROUND

Actinic damage is responsible for the development of multiple, recurrent non-melanoma skin cancers (NMSCs), including actinic keratoses (AKs). Photodynamic therapy (PDT) and imiquimod cream (IMIQ) 5% are recommended as field-directed treatment options.

OBJECTIVES

To compare efficacy and safety of methyl aminolevulinate (MAL)-PDT vs. IMIQ 5% in the prevention of new NMSCs development patients with field changes.

METHODS

Patients with field cancerization of the face or scalp were randomized to receive MAL-PDT on one side, and IMIQ 5% on the mirror field. The primary endpoint was the number of new lesions on the treated fields during a 12-month follow-up period. Secondary assessments included adverse events and patient preference.

RESULTS

Forty-four patients completed the study. MAL-PDT and IMIQ did not differ concerning the primary endpoint, as there was no statistically significant difference in terms of development of new NMSCs at any point of follow-up. Both treatment regimens were safe and well tolerated. Patients' preference based on the procedure, response rates and future choice favoured MAL-PDT.

CONCLUSIONS

MAL-PDT and IMIQ 5% are safe and well-tolerated treatments that equally prevent development of new AKs in patients suffering from field changes. MAL-PDT treatment appears to be superior in terms of patients' preference.

Spanish adaptation of the European guidelines for the evaluation and treatment of actinic keratosis

Current trends in our setting indicate that the prevalence of actinic keratosis and similar diseases will increase in coming years and impose a greater burden on health care resources. A long list of clinical features must be taken into account when approaching the treatment of actinic keratosis. Until recently, therapeutic approaches focused solely on ablative procedures and the treatment of individual lesions and did not take into account areas of field cancerization. Now that the therapeutic arsenal has grown, standardized criteria are needed to guide the optimal choice of treatment for each patient. The elaboration of evidence-based consensus recommendations for the diagnosis and treatment of actinic keratosis generates knowledge that will help clinicians to deliver the highest level of care possible, standardizing decision-making processes and enhancing awareness among all the health professionals involved in the care pathway.

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.

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.

[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.

Spotlighting the role of photodynamic therapy in cutaneous malignancy: an update and expansion

BACKGROUND

Topical photodynamic therapy (PDT) is an option for the treatment of cutaneous malignancy.

OBJECTIVE

To present an update and expansion on a previous review of the use of PDT in the current literature in the treatment of actinic keratoses (AK), superficial and nodular basal cell carcinoma (sBCC, nBCC), squamous cell carcinoma (SCC), Bowen's disease, cutaneous T cell lymphoma (CTCL), malignant melanoma, and its use in chemoprevention.

METHODS

Extensive PubMed search January 2013.

RESULTS AND CONCLUSIONS

We find sufficient evidence to recommend the use of PDT in certain patients in the treatment of AK, Bowen's disease, sBCC, and nBCC. It is especially useful in those with contraindications to surgery, widespread areas of involvement, and large lesions. Not only can it be considered superior to other therapies as far as recovery time, tolerance, and cosmetic outcomes, but it also should be considered, when indicated, as first-line treatment in the above conditions. Investigations continue for the use of PDT in the treatment of melanoma, SCC, chemoprevention, and CTCL.

The toll-like receptor agonist imiquimod is active against prions

Using a yeast-based assay, a previously unsuspected antiprion activity was found for imiquimod (IQ), a potent Toll-like receptor 7 (TLR7) agonist already used for clinical applications. The antiprion activity of IQ was first detected against yeast prions [PSI⁺] and [URE3], and then against mammalian prion both ex vivo in a cell-based assay and in vivo in a transgenic mouse model for prion diseases. In order to facilitate structure-activity relationship studies, we conducted a new synthetic pathway which provides a more efficient means of producing new IQ chemical derivatives, the activity of which was tested against both yeast and mammalian prions. The comparable antiprion activity of IQ and its chemical derivatives in the above life forms further emphasizes the conservation of prion controlling mechanisms throughout evolution. Interestingly, this study also demonstrated that the antiprion activity of IQ and IQ-derived compounds is independent from their ability to stimulate TLRs. Furthermore, we found that IQ and its active chemical derivatives inhibit the protein folding activity of the ribosome (PFAR) in vitro.

Trial Watch: Toll-like receptor agonists for cancer therapy

Toll-like receptors (TLRs) have long been known for their ability to initiate innate immune responses upon exposure to conserved microbial components such as lipopolysaccharide (LPS) and double-stranded RNA. More recently, this family of pattern recognition receptors has been attributed a critical role in the elicitation of anticancer immune responses, raising interest in the development of immunochemotherapeutic regimens based on natural or synthetic TLR agonists. In spite of such an intense wave of preclinical and clinical investigation, only three TLR agonists are currently licensed by FDA for use in cancer patients: bacillus Calmette–Guérin (BCG), an attenuated strain of Mycobacterium bovis that operates as a mixed TLR2/TLR4 agonist; monophosphoryl lipid A (MPL), a derivative of Salmonella minnesota that functions as a potent agonist of TLR4; and imiquimod, a synthetic imidazoquinoline that activates TLR7. One year ago, in the August and September issues of OncoImmunology, we described the main biological features of TLRs and discussed the progress of clinical studies evaluating the safety and therapeutic potential of TLR agonists in cancer patients. Here, we summarize the latest developments in this exciting area of research, focusing on preclinical studies that have been published during the last 13 mo and clinical trials launched in the same period to investigate the antineoplastic activity of TLR agonists.