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

A Trojan horse approach for efficient drug delivery in photodynamic therapy: focus on taxanes

Photodynamic therapy is an effective method for the treatment of several types of cancerous and noncancerous diseases. The key to the success of this treatment method is effective drug delivery to the site of action, for instance, a tumor. This ensures not only the high effectiveness of the therapy but also the suppression of side effects. But how to achieve effective targeted delivery? Lately, much attention has been paid to systems based on the so-called Trojan horse model, which is gaining increasing popularity. The principle of this model is that the effective drug is hidden in the internal structure of a nanoparticle, liposome, or nanoemulsion and is released only at the site of action. In this review article, we focus on drugs from the group of mitotic poisons, taxanes, and their use with photosensitizers in combined therapy. Here, we discuss the possibilities of how to improve the paclitaxel and docetaxel bioavailability, as well as their specific targeting for use in combined photo- and chemotherapy. Moreover, we also present the state of the art multifunctional drugs based on cabazitaxel which, owing to a suitable combination with photosensitizers, can be used besides photodynamic therapy and also in photoacoustic imaging or sonodynamic therapy.

Targeted implementation strategies of precise photodynamic therapy based on clinical and technical demands

With the development of materials science, photodynamic-based treatments have gradually entered clinics. Photodynamic therapy is ideal for cancer treatment due to its non-invasive and spatiotemporal properties and is the first to be widely promoted in clinical practice. However, the shortcomings resulting from the gap between technical and clinical demands, such as phototoxicity, low tissue permeability, and tissue hypoxia, limit its wide applications. This article reviews the available data regarding the pharmacological and clinical factors affecting the efficacy of photodynamic therapy, such as photosensitizers and oxygen supply, disease diagnosis, and other aspects of photodynamic therapy. In addition, the synergistic treatment of photodynamic therapy with surgery and nanotechnology is also discussed, which is expected to provide inspiration for the design of photodynamic therapy strategies.

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.

New developments in skin-directed treatments of cutaneous T-cell lymphoma

The therapeutic approach for mycosis fungoides, the most common type of primary cutaneous T-cell lymphoma, is based mainly on the stage of the disease, and skin-directed treatment is recommended by all international guidelines as the first-line treatment in early-stage disease. Skin-directed treatments may be also given in combination with systemic therapies in early-stage mycosis fungoides patients recalcitrant to different types of skin-directed treatments, or in certain patients with high-risk features. Advanced-stage mycosis fungoides is treated mainly with systemic treatments, which may be combined with skin-directed treatments. Due to the rarity of mycosis fungoides, controlled clinical trials of the different skin-directed treatment modalities are almost non-existent, with a few exceptions, and therefore recommendations are largely based on cohort studies and expert opinion. This paper reviews the new developments in skin-directed treatments and provides an update on new studies of already well-known therapies, and an update on novel treatments.

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.

Epigenetically Enhanced Photodynamic Therapy (ePDT) is Superior to Conventional Photodynamic Therapy for Inducing Apoptosis in Cutaneous T-Cell Lymphoma

Conventional photodynamic therapy with aminolevulinate (ALA-PDT) selectively induces apoptosis in diseased cells and is highly effective for treating actinic keratoses. However, similar results are achieved only in a subset of patients with cutaneous T-cell lymphoma (CTCL). Our previous work shows that the apoptotic resistance of CTCL correlates with low expression of death receptors like Fas cell surface death receptor (FAS), and that methotrexate upregulates FAS by inhibiting the methylation of its promoter, acting as an epigenetic derepressor that restores the susceptibility of FAS-low CTCL to caspase-8-mediated apoptosis. Here, we demonstrate that methotrexate increases the response of CTCL to ALA-PDT, a concept we refer to as epigenetically enhanced PDT (ePDT). Multiple CTCL cell lines were subjected to conventional PDT versus ePDT. Apoptotic biomarkers were analyzed in situ with multispectral imaging analysis of immunostained cells, a method that is quantitative and 5× more sensitive than standard immunohistology for antigen detection. Compared to conventional PDT or methotrexate alone, ePDT led to significantly greater cell death in all CTCL cell lines tested by inducing greater activation of caspase-8-mediated extrinsic apoptosis. Upregulation of FAS and/or tumor necrosis factor-related apoptosis-inducing ligand pathway components was observed in different CTCL cell lines. These findings provide a rationale for clinical trials of ePDT for CTCL.

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 in dermatology: current concepts in the treatment of skin cancer

Photodynamic therapy is a treatment modality that is developing rapidly and increasing in utilization within various medical specialties, including dermatology. This technique requires the presence of a photosensitizer, light energy and molecular oxygen to selectively destroy pathologic cells. A thorough understanding of photobiology and tissue optics is necessary to correctly and effectively utilize photodynamic therapy in dermatology. Photodynamic therapy has been approved by the US Food and Drug Administration to treat actinic keratoses. In Europe, photodynamic therapy is currently being used in the treatment of actinic keratoses and basal cell carcinoma. Other off-label uses of photodynamic therapy have included cutaneous lesions of Bowen's disease, psoriasis, cutaneous T-cell lymphoma and acne. Most recently, photodynamic therapy has been employed in photorejuvenation. The advantages of photodynamic therapy include the capacity for noninvasive targeted therapy via topical application of the drug and local irradiation of involved areas, as well as the ability to generate excellent cosmetic results with minimal discomfort. This review summarizes the fundamentals of photodynamic therapy and its role in the treatment of cutaneous disorders, particularly skin malignancies.

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.

Cutaneous penetration of the topically applied photosensitizer Pc 4 as detected by intravital 2-photon laser scanning microscopy

The fundamental mechanism of photodynamic therapy (PDT)-induced cell death has been characterized, but early critical PDT events in vivo remain incompletely defined. With the recent development in advanced fluorescence imaging modalities, such as intravital 2-photon laser scanning microscopy (2P-LSM), researchers are now able to investigate and visualize biological processes with high resolution in real time. This powerful imaging technology allows deep tissue visualization with single-cell resolution, thus providing dynamic information on the 3-dimensional architectural makeup of the tissue. The main goal of this study was to determine the cutaneous penetration of a topically applied photosensitizer, the silicon phthalocyanine Pc 4, into the skin of live animals and to assess the effective absorption of Pc 4 through the skin barrier. Our 2P-LSM images indicate that Pc 4 penetrates to the epidermal/dermal junction of mouse skin. The data also indicate that the degree of Pc 4 absorption is dose dependent. These findings represent initial steps that may help in improving the clinical utilization of topical Pc 4-PDT.

Management of cutaneous T cell lymphoma: new and emerging targets and treatment options

Cutaneous T cell lymphomas (CTCL) clinically and biologically represent a heterogeneous group of non-Hodgkin lymphomas, with mycosis fungoides and Sézary syndrome being the most common subtypes. Over the last decade, new immunological and molecular pathways have been identified that not only influence CTCL phenotype and growth, but also provide targets for therapies and prognostication. This review will focus on recent advances in the development of therapeutic agents, including bortezomib, the histone deacetylase inhibitors (vorinostat and romidepsin), and pralatrexate in CTCL.

Successful cutaneous delivery of the photosensitizer silicon phthalocyanine 4 for photodynamic therapy

BACKGROUND

 Photodynamic therapy (PDT) has been shown to be effective in the treatment of malignancies of a variety of organ systems, including the lungs, bladder, gastrointestinal tract and skin. Cutaneous lesions serve as ideal targets of PDT because of the accessibility of the skin to light. To achieve optimum results, the photosensitizer must be delivered effectively into the target layers of the skin within a practical timeframe, via noninvasive methods.

AIM

To determine whether topical application of a second-generation photosensitizer, silicon phthalocyanine (Pc) 4 [SiPc(OSi(CH3)2 (CH2)3 N(CH3)2)(OH)], results in effective penetration of the skin barrier.

METHODS

Penetration of Pc 4 was evaluated using standard Franz-type vertical diffusion cell experiments on surrogate materials (silicone membranes) and laser-scanning confocal microscopy of normal skin biopsy samples from human volunteers.

RESULTS

The Franz diffusion data indicate that Pc 4 formulated in an ethanol/propylene glycol solution (70/30%, v/v) can penetrate the membrane at a flux that is appreciable and relatively invariant. Using the same formulation, Pc 4 uptake could be detected in human skin via laser-scanning confocal microscopy.

CONCLUSION

After topical application, Pc 4 is absorbed into the epidermis in as little as 1 h, and the absorption increased with increasing time and dose. Pc 4 can be effectively delivered into human skin via topical application. The data also suggest that the degree of penetration is time- and dose-dependent.

Aminolevulinic Acid (ALA) as a Prodrug in Photodynamic Therapy of Cancer

Aminolevulinic acid (ALA) is an endogenous metabolite normally formed in the mitochondria from succinyl-CoA and glycine. Conjugation of eight ALA molecules yields protoporphyrin IX (PpIX) and finally leads to formation of heme. Conversion of PpIX to its downstream substrates requires the activity of a rate-limiting enzyme ferrochelatase. When ALA is administered externally the abundantly produced PpIX cannot be quickly converted to its final product - heme by ferrochelatase and therefore accumulates within cells. Since PpIX is a potent photosensitizer this metabolic pathway can be exploited in photodynamic therapy (PDT). This is an already approved therapeutic strategy making ALA one of the most successful prodrugs used in cancer treatment.

Recent advances in the prevention and treatment of skin cancer using photodynamic therapy

Photodynamic therapy (PDT) is a noninvasive procedure that involves a photosensitizing drug and its subsequent activation by light to produce reactive oxygen species that specifically destroy target cells. Recently, PDT has been widely used in treating non-melanoma skin malignancies, the most common cancer in the USA, with superior cosmetic outcomes compared with conventional therapies. The topical 'photosensitizers' commonly used are 5-aminolevulinic acid (ALA) and its esterified derivative methyl 5-aminolevulinate, which are precursors of the endogenous photosensitizer protoporphyrin IX. After treatment with ALA or methyl 5-aminolevulinate, protoporphyrin IX preferentially accumulates in the lesion area of various skin diseases, which allows not only PDT treatment but also fluorescence diagnosis with ALA-induced porphyrins. Susceptible lesions include various forms of non-melanoma skin cancer such as actinic keratosis, basal cell carcinoma and squamous cell carcinoma. The most recent and promising developments in PDT include the discovery of new photosensitizers, the exploitation of new drug delivery systems and the combination of other modalities, which will all contribute to increasing PDT therapeutic efficacy and improving outcome. This article summarizes the main principles of PDT and its current clinical use in the management of non-melanoma skin cancers, as well as recent developments and possible future research directions.

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.

The role of porphyrin chemistry in tumor imaging and photodynamic therapy

In recent years several review articles and books have been published on the use of porphyrin-based compounds in photodynamic therapy (PDT). This critical review is focused on (i) the basic concept of PDT, (ii) advantages of long-wavelength absorbing photosensitizers (PS), (iii) a brief discussion on recent advances in developing PDT agents, and (iv) the various synthetic strategies designed at the Roswell Park Cancer Institute, Buffalo, for developing highly effective long-wavelength PDT agents and their utility in constructing the conjugates with tumor-imaging and therapeutic potential (Theranostics). The clinical status of certain selected PDT agents is also summarized (205 references).

Guidelines for topical photodynamic therapy: update

Multicentre randomized controlled studies now demonstrate high efficacy of topical photodynamic therapy (PDT) for actinic keratoses, Bowen's disease (BD) and superficial basal cell carcinoma (BCC), and efficacy in thin nodular BCC, while confirming the superiority of cosmetic outcome over standard therapies. Long-term follow-up studies are also now available, indicating that PDT has recurrence rates equivalent to other standard therapies in BD and superficial BCC, but with lower sustained efficacy than surgery in nodular BCC. In contrast, current evidence does not support the use of topical PDT for squamous cell carcinoma. PDT can reduce the number of new lesions developing in patients at high risk of skin cancer and may have a role as a preventive therapy. Case reports and small series attest to the potential of PDT in a wide range of inflammatory/infective dermatoses, although recent studies indicate insufficient evidence to support its use in psoriasis. There is an accumulating evidence base for the use of PDT in acne, while detailed study of an optimized protocol is still required. In addition to high-quality treatment site cosmesis, several studies observe improvements in aspects of photoageing. Management of treatment-related pain/discomfort is a challenge in a minority of patients, and the modality is otherwise well tolerated. Long-term studies provide reassurance over the safety of repeated use of PDT.

Photodynamic therapy in dermatology--an update 2008

SUMMARY

Photodynamic therapy (PDT) is used for the prevention and treatment of non-melanoma skin cancer. Until recently, clinically approved indications have been restricted to actinic keratoses, nodular and superficial basal cell carcinoma, and--since 2006--Bowen disease. However, the range of indications has been expanding continuously. PDT is also used for the treatment of non-malignant conditions such as acne vulgaris and leishmaniasis, as well as for treating premature skin aging due to sun exposure. Here, PDT is used for the stimulation of immunomodulatory effects in contrast to the induction of necrosis and apoptosis as produced in the treatment of skin tumors. The porphyrin precursor 5-aminolevulinic acid (ALA) or its methyl ester (MAL, so far the only approved formulation in Europe) is applied topically as photosensitizer to exclude systemic reactions. Possible light sources include lasers as well as incoherent light sources; irradiation with incoherent light sources is cheaper and more appropriate for large treatment areas. The main advantages of PDT in comparison to other treatment modalities are its excellent cosmetic results and its high remission rates despite low invasiveness.This article provides up-to-date information about PDT with focus on recently published studies.

Mycosis fungoides

Mycosis fungoides (MF) constitutes the most frequent cutaneous T-cell lymphoma. Sezary syndrome is considered by some authors to be an erythrodermic leukemic variant of MF, but is classified separately in the new WHO-EORT classification of cutaneous lymphomas. MF usually occurs in old adults with a 2:1 male to female ratio. Its prognosis is variable and strongly conditioned by the extent and type of skin involvement and presence of extracutaneous disease. Patients with stage IA-disease have an excellent prognosis with an overall long-term life expectancy that is similar to an age-, sex-, and race-matched control population. Almost all patients with stage IA MF will die from causes other than MF, with a median survival >33 years. Only 9% of these patients will progress to more extended disease. Patients with stage IB or IIA have a median survival greater than 11 years. These patients with T2 disease have a likelihood of disease progression of 24% and nearly 20% die of MF. Subgroups with stage IB or IIA have similar prognosis. Patients with cutaneous tumors or generalized erythroderma have a median survival of 3 and 4.5 years, respectively. The majority of these patients will die of MF. Extracutaneous dissemination is observed in less than 10% of patients with patch or plaque disease and in 30-40% of patients with tumors or generalized erythrodermatous involvement. Extracutaneous involvement is directly correlated to the extent of cutaneous disease. The most commonly involved organs are lung, spleen, liver, and gastrointestinal tract. Patients with extracutaneous disease at presentation involving either lymph nodes or viscera have a median survival of <1.5 years. Patients with plaque-type or erythrodermic MF may develop cutaneous tumors with large cell histology, often expressing CD30, which share a common clonal origin as observed in their preexisting MF and are associated with a less favourable outcome.

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.

A clinical review of PDT for cutaneous malignancies

More critical than for most other anatomy, intervention to cutaneous malignancy must not only be therapeutically successful but also achieve excellent cosmetic and functional outcome. As it can achieve those ends, PDT has moved to the forefront in the management of skin cancer. A number of well designed clinical trials and large patient series have reported outstanding outcomes for many histologies. This paper will review the rationale and outcomes of cutaneous PDT to malignancy using both topical and systemic photosensitizers. The benefits and drawbacks of cutaneous PDT are also examined.

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.

Irradiation therapy: from UV light to electron beam

Irradiation therapy represents one of the mainstay treatment modalities in cutaneous T-cell lymphomas. For the patch and plaque stages UV therapy is mostly used. Among UV light treatment broadband UVB is less effective than narrow band UVB. If these modalities are not sufficient, then PUVA therapy is indicated and might be used in even more advanced stages, including the erythrodermic stage of the disease. For resistant cases and remaining tumors, conventional radiotherapy or electron beam therapy is the treatment of a choice. If the disease is widespread, total skin electron beam radiation gives excellent results. One should not forget the possibility of combining UV therapy with radiotherapy or electron beam radiation, or with chemo- and immunotherapy respectively.

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.

A review of progress in clinical photodynamic therapy

Photodynamic therapy (PDT) has received increased attention since the regulatory approvals have been granted to several photosensitizing drugs and light applicators worldwide. Much progress has been seen in basic sciences and clinical photodynamics in recent years. This review will focus on new developments of clinical investigation and discuss the usefulness of various forms of PDT techniques for curative or palliative treatment of malignant and non-malignant diseases.