Photodynamic therapy of cutaneous lymphoma using 5-aminolevulinic acid topical application

Photodynamic therapy in the treatment of patients with mycosis fungoides

The review highlights the current understanding of the epidemiology, etiology, pathogenesis, existing classifications of mycosis fungoides. Methods for diagnosis and treatment of the pathology are described, among which photodynamic therapy (PDT) plays an important role. The main advantages of PDT for mycosis fungoides include the absence of systemic toxicity, non-invasiveness, selectivity, absence of carcinogenic potential, the possibility of repeated courses of treatment, and good cosmetic results. This review collects and analyzes the results of clinical trials of PDT in patients with mycosis fungoides. The analysis showed high efficiency of PDT in patients with mycosis fungoides with isolated or limited spots and plaques. PDT can be considered as the therapy of choice in patients with facial lesions when a good cosmetic result is one of the main requirements, and radiation therapy, nitrogen mustard or carmustine can leave permanent and visible scars. Plaques located in the axillary or inguinal skin folds that are inaccessible to phototherapy can also be treated with PDT.

Photodynamic therapy in the treatment of patients with mycosis fungoides

The review highlights the current understanding of the epidemiology, etiology, pathogenesis, existing classifications of mycosis fungoides. Methods for diagnosis and treatment of the pathology are described, among which photodynamic therapy (PDT) plays an important role. The main advantages of PDT for mycosis fungoides include the absence of systemic toxicity, non-invasiveness, selectivity, absence of carcinogenic potential, the possibility of repeated courses of treatment, and good cosmetic results. This review collects and analyzes the results of clinical trials of PDT in patients with mycosis fungoides. The analysis showed high efficiency of PDT in patients with mycosis fungoides with isolated or limited spots and plaques. PDT can be considered as the therapy of choice in patients with facial lesions when a good cosmetic result is one of the main requirements, and radiation therapy, nitrogen mustard or carmustine can leave permanent and visible scars. Plaques located in the axillary or inguinal skin folds that are inaccessible to phototherapy can also be treated with PDT.

Photodynamic therapy of cutaneous T-cell lymphoma cell lines mediated by 5-aminolevulinic acid and derivatives

The delta-amino acid 5-aminolevulinic acid (ALA), is the precursor of the endogenous photosensitiser Protoporphyrin IX (PpIX), and is currently approved for Photodynamic Therapy (PDT) of certain superficial cancers. However, ALA-PDT is not very effective in diseases in which T-cells play a significant role. Cutaneous T-cell lymphomas (CTCL) is a group of non-Hodgkin malignant diseases, which includes mycosis fungoides (MF) and Sézary syndrome (SS). In previous work, we have designed new ALA esters synthesised by three-component Passerini reactions, and some of them showed higher performance as compared to ALA. This work aimed to determine the efficacy as pro-photosensitisers of five new ALA esters of 2-hydroxy-N-arylacetamides (1f, 1 g, 1 h, 1i and 1 k) of higher lipophilicity than ALA in Myla cells of MF and HuT-78 cells of SS. We have also tested its effectiveness against ALA and the already marketed ALA methyl ester (Me-ALA) and ALA hexyl ester (He-ALA). Both cell Myla and SS cells were effectively and equally photoinactivated by ALA-PDT. Besides, the concentration of ALA required to induce half the maximal porphyrin synthesis was 209 μM for Myla and 169 μM for HuT-78 cells. As a criterion of efficacy, we calculated the concentration of the ALA derivatives necessary to induce half the plateau porphyrin values obtained from ALA. These values were achieved at concentrations 4 and 12 times lower compared to ALA, according to the derivative used. For He-ALA, concentrations were 24 to 25 times lower than required for ALA for inducing comparable porphyrin synthesis in both CTCL cells. The light doses for inducing 50% of cell death (LD50) for He-ALA, 1f, 1 g, 1 h and 1i were around 18 and 25 J/cm² for Myla and HuT-78 cells respectively, after exposure to 0.05 mM concentrations of the compounds. On the other hand, the LD50s for the compound 1 k were 40 and 57 J/cm² for Myla and HuT-78, respectively. In contrast, 0.05 mM of ALA and Me-ALA did not provoke photokilling since the concentration employed was far below the porphyrin saturation point for these compounds. Our results suggest the potential use of ALA derivatives for topical application in PDT treatment of MF and extracorporeal PDT for the depletion of activated T-cells in SS.

Synthesis and evaluation of novel chlorophyll a derivatives as potent photosensitizers for photodynamic therapy

Chlorophyll a exhibits excellent photosensitive activity in photosynthesis. The unstability limited its application as photoensitizer drug in photodynamic therapy. Here a series of novel chlorophyll a degradation products pyropheophorbide-a derivatives were synthesized and evaluated for lung cancer in PDT. These compounds have strong absorption in 660-670 nm with high molar extinction coefficient, and fluorescence emission in 660-675 nm upon excitation with 410-415 nm light. They all have much higher ROS yields than pyropheophorbide-a, and compound 10 was even higher than [3-(1-hexyloxyethyl)]-pyrophoeophorbide a (HPPH). Distinctive phototoxicity was observed in vitro and the inhibition effect was in light dose-dependent and drug dose-dependent style. They can effectively inhibit the growth of lung tumor in vivo. Among them, compound 8 and 11 have outstanding photodynamic anti-tumor effects without obvious skin photo-toxicity, so they can act as new drug candidates for photodynamic therapy.

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 as an alternative treatment for mycosis fungoides: a systemic review and meta-analysis

INTRODUCTION

Mycosis fungoides is the most common cutaneous T cell lymphoma. Selection of appropriate treatment for mycosis fungoides (MF) is based on prognostic factors and overall clinical stage at diagnosis. In the past decade, clinical success has been reported using photodynamic therapy (PDT) as an alternative target-specific therapy to treat mycosis fungoides. This review aimed to summarize the current advances in management of mycosis fungoides by administration of photodynamic therapy.

EVIDENCE ACQUISITION

Twenty-four articles, published between 1994 and 2017, were reviewed to assess the efficacy of PDT for MF.

EVIDENCE SYNTHESIS

Methyl-aminolevulinic acid has increased lipophilic properties; red light at around 630 nm achieves deepest and best tissue penetration. However, the total number of PDT sessions depends on the clinical response.

CONCLUSIONS

Further multicenter clinical studies are warranted to assess the cost-effectiveness of PDT.

Photodynamic therapy as an alternative treatment for relapsed or refractory mycosis fungoides: A systemic review

Mycosis fungoides is the most common cutaneous T-cell lymphoma. It is characterized by slow progress over years to decades, developing from patches to infiltrated plaques, and sometimes to tumors. Therapies such as localized chemotherapy, photochemotherapy and radiotherapy are often employed when lesions of refractory or relapsing mycosis fungoides are resistant to conventional therapies. However, these methods have acute or chronic side effects and toxicity, which may accumulate with repeated and protracted treatment cycles. Photodynamic therapy is a promising, well-tolerated option for the treatment of localized lesions with excellent cosmetic outcomes. In this article, we systematically reviewed and discussed clinical application of photodynamic therapy in relapsed or refractory mycosis fungoides. There are 20 papers included in this review article.

Photodynamic therapy with topical aminolevulinic acid

Photodynamic therapy (PDT) is a relatively new therapy in dermatology that uses the topical application of a porphyrin derivative to selectively destroy a cutaneous target. The action is implemented by the application of a specific light frequency. The ability of porphyrin to selectively target tumor tissue has been known since the 1960s. In the late 1970s, the underlying mechanism was defined, and Dougherty’s discovery of the first chromophore led to the production and commercialization of Photofrin^®. Many other chromophores that can act as photosensitizers have been studied since then, with aminolevulinic acid currently the most commonly used chromophore in clinical practice. PDT is simple, minimally invasive and can be administered on an outpatient basis. The efficacy of PDT has been proven for actinic keratosis, Bowen’s disease and basal cell carcinoma; another of its well-known applications is the treatment of photoaging. Indications for its use are continuously increasing, and promising results are reported for various skin diseases. In this paper we report the mechanism of action of PDT with aminolevulinic acid, the literature concerning the most common diseases treated with PDT and the subsequent level of evidence.

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.

Photodynamic therapy with methyl-aminolevulinic acid for paucilesional mycosis fungoides: a prospective open study and review of the literature

BACKGROUND

Publications reporting photodynamic therapy (PDT) in mycosis fungoides (MF) are rare, involve small samples, and are difficult to compare because of a lack of technical standardization.

OBJECTIVE

We sought to assess PDT effectiveness and tolerability in early-stage MF using a strict reproducible procedure.

METHODS

This was a prospective study conducted in Nantes University Hospital, France, including patients older than 18 years with histologically proven MF (stage IA or IB). Methyl-aminolevulinic acid-PDT sessions were repeated monthly for 6 months. Clinical and histologic responses were assessed 1 month after the last session. Patient satisfaction was assessed by telephone survey.

RESULTS

Twelve patients (with 29 lesions) were treated with PDT. An objective response in target lesions was obtained in 75% of patients. Response rates were similar between plaques and patches but higher in sun-protected compared with sun-exposed areas (trend without reaching significance). During PDT, new lesions appeared in 5 of 12 patients in untreated areas. Most patients were highly satisfied and preferred PDT to the topical chemotherapy previously used.

LIMITATIONS

PDT procedure criteria selection was partially arbitrary.

CONCLUSIONS

In early-stage MF, PDT is effective and appreciated (especially when compared with conventional topical chemotherapy). Unilesional and paucilesional forms and lesions in sun-protected areas are to be preferred.

Photodynamic therapy in mycosis fungoides

Photodynamic therapy involves the topical application of a photosensitizer to a lesion, which is then subsequently exposed to a light source. It is mainly used in the nonsurgical treatment of nonmelanoma skin cancer, in which it achieves good response and an excellent cosmetic result. In the last 10 years, photodynamic therapy has also been used with some success in the treatment of plaque-stage mycosis fungoides and has emerged as an alternative to skin-directed therapies. Its main advantages are the good response to treatment, lack of toxicity, and excellent cosmetic results. This article reviews the literature and the practical application of photodynamic therapy in mycosis fungoides.

Emerging treatment options for early mycosis fungoides

Mycosis fungoides is a candidate for skin-directed therapies in its initial stages. In recent years, therapeutic options outside of the normal treatment recommendations such as topical imiquimod, topical tazarotene, topical methotrexate, excimer light sources, and photodynamic therapy have been published with variable results. These alternatives have been useful in cases of localized mycosis fungoides that do not respond to routine treatments; nevertheless, more studies on these methods are still needed. This article summarizes the literature and data that are known so far about these treatments.

Silicon phthalocyanine (Pc 4) photodynamic therapy is a safe modality for cutaneous neoplasms: results of a phase 1 clinical trial

BACKGROUND

Photodynamic therapy (PDT) is a non-invasive treatment for non-melanoma skin cancer. However, PDT systems currently used clinically have limitations such as pain and superficial tissue penetration. The silicon phthalocyanine Pc 4 is a second-generation photosensitizer with peak absorption in the far red at 675 nm.

OBJECTIVE

To assess the safety and tolerability of topically applied Pc 4 followed by red light (Pc 4-PDT) in treating cutaneous neoplasms.

STUDY DESIGN/MATERIALS AND METHODS

Forty three adults with a diagnosis of neoplasms including actinic keratoses, Bowen's disease, squamous cell carcinoma, basal cell carcinoma, or mycosis fungoides were treated with a single administration of Pc 4-PDT and followed for 14 days. The study utilized a light and Pc 4 dose escalation design in sequential groups of three subjects each.

RESULTS

Pc 4-PDT was well tolerated with no significant local toxicity or increased photosensitivity. It has promising biologic effects, particularly in mycosis fungoides where 14 of 35 subjects demonstrated a clinical response, which correlates with Pc 4-PDT-induced apoptosis, as measured by increased active caspase-3 in the treated skin lesions.

CONCLUSIONS

Pc 4-PDT is a safe and tolerable treatment modality that effectively triggers apoptosis in cutaneous neoplasms such as mycosis fungoides.

Innovative therapy of cutaneous T-cell lymphoma: beyond psoralen and ultraviolet light and nitrogen mustard

Cutaneous T-cell lymphoma is a malignancy of skin-homing T cells. This unique population of lymphocytes requires alternative therapies to those used in nodal lymphomas. Although phototherapy and nitrogen mustard have been standard treatments for decades, newer therapies have been arriving with increased frequency. Moreover, some therapies, currently used to treat other diseases, have been used with good effect. These innovative therapies are discussed, with review of current data and examples of how these therapies may be used today.

Monitoring Pc 4 photodynamic therapy in clinical trials of cutaneous T-cell lymphoma using noninvasive spectroscopy

Silicon phthalocyanine Pc 4 photodynamic therapy (Pc 4-PDT) has emerged as a potentially effective treatment for cutaneous T-cell lymphoma (CTCL). Noninvasive reflectance and fluorescence spectroscopy before, during, and after PDT may provide useful dose metrics and enable therapy to be tailored to individual lesions. We present the design and implementation of a portable bedside spectroscopy system for initial clinical trials of Pc 4-PDT of CTCL. Reflectance and fluorescence spectra were obtained from an early stage CTCL patient throughout the course of the PDT treatment. Preliminary patient data show a significant effect of Pc 4 on the tissue absorption, modest Pc 4 photobleaching, and heterogeneity of Pc 4 within and between the lesions.

The optimal use of bexarotene in cutaneous T-cell lymphoma

The management goal in cutaneous T-cell lymphomas (CTCLs) is to improve symptoms and induce remission. Early-stage disease is generally treated with skin-directed therapies. However, if these do not control the disease, systemic therapy becomes necessary. Bexarotene, a novel rexinoid, is an oral, noncytotoxic drug that has been approved in Europe for the treatment of refractory advanced-stage CTCL and in the U.S.A. for refractory CTCL. We provide guidance on the use of bexarotene in the management of CTCL, based on data from phase II/III clinical trials and the authors' clinical experience, and suggest how the potential of the drug can be maximized. The clinical trial results with bexarotene are reviewed, especially in comparison with interferon-alpha, which is the other commonly used noncytotoxic systemic therapy for CTCL. A treatment algorithm for bexarotene in refractory CTCL is suggested. As bexarotene may take time to achieve a maximum response, this algorithm recommends that therapy should be continued for a sufficient period to allow for a delayed onset of action. In addition, possible combination therapies with bexarotene are discussed. We conclude that bexarotene is effective in the management of CTCL, and has the advantage of oral administration. An on-going randomized clinical trial comparing psoralen plus ultraviolet A (PUVA) with PUVA plus bexarotene will provide valuable information about this combination regimen in early-stage disease, but further data are needed on the relative efficacies of other combination therapies with bexarotene in CTCL.

Mapping of oxidative stress responses of human tumor cells following photodynamic therapy using hexaminolevulinate

Background

Photodynamic therapy (PDT) involves systemic or topical administration of a lesion-localizing photosensitizer or its precursor, followed by irradiation of visible light to cause singlet oxygen-induced damage to the affected tissue. A number of mechanisms seem to be involved in the protective responses to PDT, including activation of transcription factors, heat shock proteins, antioxidant enzymes and apoptotic pathways.

Results

In this study, we address the effects of a destructive/lethal hexaminolevulinate (HAL) mediated PDT dose on the transcriptome by using transcriptional exon evidence oligo microarrays. Here, we confirm deviations in the steady state expression levels of previously identified early defence response genes and extend this to include unreported PDT inducible gene groups, most notably the metallothioneins and histones. HAL-PDT mediated stress also altered expression of genes encoded by mitochondrial DNA (mtDNA). Further, we report PDT stress induced alternative splicing. Specifically, the ATF3 alternative isoform (deltaZip2) was up-regulated, while the full-length variant was not changed by the treatment. Results were independently verified by two different technological microarray platforms. Good microarray, RT-PCR and Western immunoblotting correlation for selected genes support these findings.

Conclusion

Here, we report new insights into how destructive/lethal PDT alters the transcriptome not only at the transcriptional level but also at post-transcriptional level via alternative splicing.

Photodynamic therapy: update 2006. Part 2: Clinical results

In several randomized, controlled studies, the application of a standard preparation containing methyl-aminolevulinate (MAL; Metvix, Galderma, F), followed by red light irradiation proved effective and well tolerated in the treatment of actinic keratosis and basal cell carcinoma, and has now been approved for clinical use in European countries. A brand name aminolevulinic acid (ALA) solution (Levulan Kerastick, Dusa Pharmaceuticals Inc., Wilmington, MA) plus blue light exposure has been approved for the treatment of actinic keratosis in the USA. Randomized and controlled studies have shown that MAL as well as ALA are also effective in the treatment of Bowen's disease. In addition, a large and growing number of open studies or case reports have evaluated its use in the treatment of a broad range of other neoplastic, inflammatory and infectious skin diseases. However, efficacy and definite advantages over standard therapies remain to be clarified because the experimental design of these studies was often poor, the number of enrolled patients was generally low, and the follow-up was shorter than 12 months. However, these studies have suggested a few possible clinical applications worthy of further investigation. A growing number of laboratory and clinical findings suggest that several new synthetic sensitizers, besides ALA and MAL, may be helpful in the treatment of non-melanoma skin cancers, melanoma metastasis, and selected inflammatory and infective skin diseases. These compounds are deliverable intravenously, have short half-lives both in the blood and skin, and are highly efficient. However, they are as of yet not approved for clinical use.

Photodynamic therapy: other uses

Mainstream uses for photodynamic therapy (PDT) in dermatology include nonmelanoma skin cancer and its precursors, acne vulgaris, photorejuvenation, and hidradenitis suppurativa. Many other dermatologic entities have been treated with PDT, including psoriasis, lichen planus, lichen sclerosus, scleroderma, cutaneous T cell lymphoma, alopecia areata, verruca vulgaris, Darier's disease and tinea infections. Nondermatologic applications include anal and vulva carcinoma, palliation of metastatic breast cancer to skin, Barrett's esophagus, and macular degeneration of the retina. PDT also has found to be useful in immunologic and inflammatory disorders, neoplasias other than skin cancer, and infections. The ability of this treatment to hone in on dysplastic epithelial and endothelial cells while retaining viability of surrounding tissue is its key feature because this leads to specific tumor destruction with cosmesis and function of the target organ intact.

Aminolevulinic Acid Photodynamic Therapy for Skin Cancers

Aminolevulinic acid photodynamic therapy (ALA-PDT) is an effective and noninvasive therapy for superficial basal cell carcinoma (BCC) and Bowen's disease. It also may have a role in the treatment of nodular BCC and other cutaneous malignancies, including localized cutaneous lymphomas. ALA-PDT offers multiple advantages over traditional treatments, including little to no scarring, excellent cosmetic results, and the ability to treat multiple lesions simultaneously. It is not an effective therapy for aggressive subtypes of BCC or for invasive squamous cell carcinoma. Finally, ALA-PDT may be a useful way to prevent new skin cancers in certain high-risk patients.

Photodynamic therapy with methylaminolevulinate as a valuable treatment option for unilesional cutaneous T-cell lymphoma

BACKGROUND

Mycosis fungoides (MF) is the most common primary cutaneous T-cell lymphoma (CTCL). Unilesional MF is characterized by a limited involvement of the skin and a chronical, though indolent course. If lesions are refractory to topical steroids, therapies such as localized chemotherapy, photochemotherapy and radiotherapy are available. However, they have several acute and chronic side-effects and toxicity may accumulate if repeated and protracted treatment cycles are delivered to refractory or relapsing lesions. The present study aims to assess the efficacy of photodynamic therapy (PDT) with topical methylaminolevulinate (MAL) in the treatment of unilesional MF.

METHODS

Five patients were enrolled who had unilesional MF that did not respond to treatment with topical steroids, localized psoralen and UVA therapy or UVA1 phototherapies. A 20% MAL (Metvix cream) cream was applied under occlusive dressing for 3 h. Soon afterwards, skin was irradiated with 37.5 J/cm(2) of red light (635+/-18 nm) delivered by an Aktilite CL128 lamp (PhotoCure ASA) with an irradiance of 86 W/cm(2) at skin level. PDT was repeated once weekly until complete clearing of the lesions was obtained, or, in the case of partial clearing, the therapy was interupted when three successive treatments provided no further improvement. All patients underwent a skin biopsy before and after PDT.

RESULTS

A complete remission was observed in four patients and a partial improvement in one. The median number of treatments was six (range 1-9). In no cases was recurrence seen at follow-up (ranging from 12 to 34 months). Treatments were well tolerated and local anesthesia was never requested.

CONCLUSION

In conclusion, here, PDT was seen to be an effective and well-tolerated treatment option for unilesional MF.

Topical photodynamic therapy for primary cutaneous B-cell lymphoma: a pilot study

Photodynamic therapy (PDT) is a treatment based on the accumulation of a photosensitizer in the target cells and their selective destruction by irradiation with visible light. In the past 10 years, several patients with cutaneous T cell lymphoma have been successfully treated. The use of PDT in cutaneous B cell lymphoma has not been reported to date. We report the successful PDT treatment of 3 patients with early primary cutaneous B cell lymphoma.

Topical photodynamic therapy

Topical photodynamic therapy is a therapeutic modality in development, thus arises grate interest among dermatologists worldwide. It is an effective therapy for actinic keratosis, superficial BCC and Bowenos disease. Treatment efficacy, good cosmetics, low risk of skin cancer, low invasiveness, low rate of adverse events, facility for treating multiple or large lesions, especially in poor healing sites and, for penile, digital and facial involvement, low general toxicity and possibility of repeating the treatments with the same efficiency, enable topical photodynamic therapy to become increasingly practiced treatment modality. Researching aimed topical photodynamic therapy to prove as a treatment modality for clinical use in other dermatoses, is in experimental phase. To answer the question when dermatologist should consider using topical photodynamic therapy treatment modatility, we are present available date.

Photodynamic Therapy

ALA-PDT is a safe, well-tolerated, and effective treatment for many dermatologic conditions. Current data most strongly support its use in the treatment of actinic damage, but further investigation into alternative uses continues. Current efficacy is limited primarily by the depth of penetration of the photosensitizing agent and the activating light source. Even with this limitation, the potential applications of PDT are numerous. As new technology is developed to overcome current restraints, the future of PDT is wide open.

Successful Treatment of Lymphadenosis benigna cutis with Topical Photodynamic Therapy with Delta-Aminolevulinic Acid

BACKGROUND

Photodynamic therapy (PDT) using topical delta-aminolevulinic acid (ALA) has been used for nonmelanoma skin cancers, including malignant cutaneous T-cell lymphomas. Moreover, PDT has been tried for benign inflammatory or infectious skin lesions.

OBJECTIVE

To evaluate the effects of ALA-PDT on skin lesions of lymphadenosis benigna cutis (LABC).

PATIENTS AND METHODS

Two 16-year-old females with solitary and infiltrated nodules were treated 5 times with topical ALA-PDT.

RESULTS

Both patients responded well and showed dramatic clinical and histopathological improvement without visible scars.

CONCLUSION

The results confirm that topical ALA-PDT is an effective and safe modality for the treatment of LABC, and that such treatment may be cosmetically beneficial.

Current management strategies for cutaneous T-cell lymphoma

Cutaneous T-Cell Lymphoma is a group of lymphomas characterized by a malignant proliferation of skin homing T cells. Prognosis is generally good and treatment is based on the stage of the disease with the goal of inducing remission. Patients with disease limited to the skin in the form of patches and plaques respond best to "skin directed therapy" with topical agents including corticosteroids, nitrogen mustard, carmustine, bexarotene gel, as well as phototherapy with ultraviolet B light, PUVA, or photodynamic therapy. Tazarotene and imiquimod show potential in the treatment of early CTCL. Patients with disease resistant to treatment or with advanced disease require more aggressive therapy in the form of total skin electron beam radiation, biologic response modifiers including interferon alpha, bexarotene, denileukin diftitox, extracorporeal photochemotherapy or combination therapy. The use of chemotherapy is used primarily for palliation. Allogeneic hematopoetic stem cell transplantation may represent a successful treatment for treatment resistant disease.

Topical photodynamic therapy for patients with therapy-resistant lesions of cutaneous T-cell lymphoma

Photodynamic therapy after topical application of 5-aminolevulinic acid is an effective therapy for nonmelanoma epithelial skin cancers. It has also been used for some cases of cutaneous T-cell lymphoma. We treated 4 patients with different cutaneous T-cell lymphomas with photodynamic therapy. Those patients had previously reached a partial remission with more conventional therapies, but single lesions had remained. In all of these cases a complete remission of these lesions was achieved. We, therefore, suggest that photodynamic therapy can be a useful additional treatment modality for patients with therapy-resistant lesions of cutaneous T-cell lymphoma.

A porphobilinogen deaminase (PBGD) Ran-binding protein interaction is implicated in nuclear trafficking of PBGD in differentiating glioma cells

Porphobilinogen deaminase (PBGD) is a rate-limiting enzyme of the heme biosynthesis pathway, whose level is elevated in various human tumors. PBGD was observed in both nuclear and cytoplasmic fractions of C6 glioma cells by immunostaining. During mitosis, chromatids were intensely stained for PBGD in comparison to the interphase chromatin. Using the yeast two-hybrid system, we identified RanBPM, the nuclear Ran-binding protein, as an interacting partner of PBGD. During butyrate-induced differentiation of C6, both nuclear and cytoplasmic PBGD levels declined as did Ran protein and its nucleotide exchange factor RCC1. N,N'-hexamethylene bis-acetamide-dependent differentiation resulted in an increase of the cytoplasmic PBGD, whereas nuclear PBGD, Ran protein and RCC1 remained unchanged. mRNA levels of PBGD remained unchanged during stimulation with both butyrate and N,N'-hexamethylene bis-acetamide. The enzymatic activity of PBGD and protoporphyrin IX synthesis in C6 cells were dependent on the differentiation induction agent. We conclude that PBGD possibly has a nuclear role in addition to its cytosolic enzymatic activity required for heme synthesis, which is related to cell transformation and differentiation.

Photodynamic therapy and topical aminolevulinic acid: an overview

Photodynamic therapy is a non-invasive technique used in the treatment of skin diseases which has various advantages, one being the ability to localize treatment to the area being treated, which is common among most photosensitizers. Aminolevulinic acid is a prodrug that is metabolized intracellularly to form the photosensitizing molecule protoporphyrin IX (PpIX). When PpIX is activated by light, cytotoxic reactive oxygen species and free radicals are generated. This phototoxic effect may cause malignant and non-malignant hyperproliferative tissue to be destroyed, to decrease in size, and to eventually disappear. The application of topical aminolevulinic acid 20% followed by the use of a blue light photodynamic therapy illuminator is indicated in the US for the treatment of non-hyperkeratotic actinic keratoses of the face or scalp. There are data suggesting that aminolevulinic acid/photodynamic therapy may also be beneficial in acne vulgaris, verrucae, psoriasis, mycosis fungoides, and human papillomavirus. This treatment modality has also proven effective in the management of skin cancer such as, Bowen disease and basal cell carcinoma. Further experience in the use of photodynamic therapy will help define its utility in the management of actinic keratosis and other dermatoses.

Topical 5-ALA photodynamic therapy for the treatment of cutaneous T-cell lymphoma

Therapeutic options for cutaneous T cell lymphoma (CTCL) include topical steroids, topical chemotherapy and phototherapy. Patients with limited disease that is unresponsive to these therapies present a particular challenge. We report successful treatment of a patient with two plaques of CTCL using topical photodynamic therapy (PDT). 5-aminolaevulinic acid (5-ALA) was applied 6-24 h preillumination with 100 J/cm2 red light. Treatment was repeated on four occasions with clinical and histological clearance. ALA-PDT may be a useful addition to the therapeutic options for CTCL. Further studies are required to define optimal treatment protocols.

Guidelines for topical photodynamic therapy: report of a workshop of the British Photodermatology Group

Topical photodynamic therapy (PDT) is effective in the treatment of certain non-melanoma skin cancers and is under evaluation in other dermatoses. Its development has been enhanced by a low rate of adverse events and good cosmesis. 5-Aminolaevulinic acid (ALA) is the main agent used, converted within cells into the photosensitizer protoporphyrin IX, with surface illumination then triggering the photodynamic reaction. Despite the relative simplicity of the technique, accurate dosimetry in PDT is complicated by multiple variables in drug formulation, delivery and duration of application, in addition to light-specific parameters. Several non-coherent and coherent light sources are effective in PDT. Optimal disease-specific irradiance, wavelength and total dose characteristics have yet to be established, and are compounded by difficulties comparing light sources. The carcinogenic risk of ALA-PDT appears to be low. Current evidence indicates topical PDT to be effective in actinic keratoses on the face and scalp, Bowen's disease and superficial basal cell carcinomas (BCCs). PDT may prove advantageous where size, site or number of lesions limits the efficacy and/or acceptability of conventional therapies. Topical ALA-PDT alone is a relatively poor option for both nodular BCCs and squamous cell carcinomas. Experience of the modality in other skin diseases remains limited; areas where there is potential benefit include viral warts, acne, psoriasis and cutaneous T-cell lymphoma. A recent British Photodermatology Group workshop considered published evidence on topical PDT in order to establish guidelines to promote the efficacy and safety of this increasingly practised treatment modality.

Nuclear distribution of porphobilinogen deaminase (PBGD) in glioma cells: a regulatory role in cancer transformation?

Recently, considerable interest has been directed to red-fluorescence photodiagnosis of brain and other tumours during surgery using the protoporphyrin IX natural precursor, 5-aminolaevulinic acid. In the present study we focused on the role of the rate-limiting enzyme porphobilinogen deaminase in glioma C6 cell activity, differentiation and sub-cellular distribution. Over-expression of the human housekeeping porphobilinogen deaminase in the glioma cells, using the housekeeping-porphobilinogen deaminase plasmid, induced a G1 cell cycle attenuation accompanied by increases in enzyme activity and c6 differentiation toward astrocytes. Visualisation of subcellular localisation of the porphobilinogen deaminase using the independent techniques of fluorescence immuno-staining with specific anti-human porphobilinogen deaminase antibodies and cellular expression of porphobilinogen deaminase fused to green fluorescent protein, revealed (unexpectedly) a major fraction of porphobilinogen deaminase in the nucleus and only a minor fraction in the cytoplasm. Both C and N terminals of porphobilinogen deaminase fused to green fluorescent protein revealed a major fraction of the newly synthesized fused porphobilinogen deaminase in the nucleus. Furthermore, newborn rat brain cells grown in a primary culture showed the same localisation pattern of porphobilinogen deaminase in the nuclei. Stimulation of C6 glioma cell differentiation by butyrate induced a marked decrease in porphobilinogen deaminase both in the nucleus and in the cytoplasm as determined by Western blotting and fluorescence immuno-localisation. These findings suggest a possible dual role for housekeeping porphobilinogen deaminase in fast dividing glioma cells, one related to the porphyrin synthesis pathway and another coupled to nuclear function, which might be linked to tumorigenesis.

Topical 5-aminolaevulinic acid photodynamic therapy for the treatment of skin conditions other than non-melanoma skin cancer

Topical 5-aminolaevulinic acid (ALA) photodynamic therapy (PDT) is used increasingly for superficial non-melanoma skin cancer (NMSC) and dysplasia. However, the relative accumulation of the photosensitizer protoporphyrin IX (PpIX) in diseased tissue is not specific for neoplastic disease, and has been shown after the application of ALA to benign proliferative skin conditions such as viral warts and psoriasis. This review appraises the quality of evidence available for the use of topical ALA-PDT in the treatment of skin conditions other than NMSC. The diseases that have been studied in most detail are recalcitrant viral warts, acne, psoriasis and cutaneous T-cell lymphoma. Publications relating to the treatment of other diseases by topical PDT are restricted to small case series or case reports. The relevant literature will be discussed and the potential for topical PDT in the treatment of several skin diseases is highlighted, although more detailed studies are required to clarify the role of PDT beyond the treatment of NMSC.

Topical 5-aminolevulinic acid and photodynamic therapy in dermatology: a minireview

Photodynamic therapy (PDT) is a treatment modality using a photosensitizer, light and oxygen to cause photochemically induced selective cell death. When exposed to light with the proper wavelength, the topically applied photosensitizer or photosensitizer precursor can activate a biomolecule through electron transfer to yield free radicals or produce singlet oxygen from energy transferred from the excited sensitizer to molecular oxygen. The tissue damage is the result of the activation of reactive singlet oxygen or free radical production. Photodynamic therapy with topical application of 5-aminolevulinic acid (ALA) is a new technique and although it remains largely experimental, it has potential application for treatment of malignant skin tumors, various precancerous and selected benign skin diseases. This technique yields not only a high percentage of good therapeutic results but also excellent cosmetic outcome. This paper reviews the recently published data on clinical ALA-based PDT in dermatology.