Single‐episode photodynamic therapy and vulval intraepithelial neoplasia type III resistant to conventional therapy

Kurwa, Habib A; Barlow, R.J.; Neill, Sarah

doi:10.1046/j.1365-2133.2000.03785.x

Cited by 36 publications

(14 citation statements)

References 12 publications

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“…Disappointing results have been seen with topical PDT for breast cancer metastases 1,48 and malignant melanoma 38 . The use of topical PDT in the treatment of vulval intraepithelial neoplasia (VIN) indicates benefit with multiple treatments, 73 with histological grade of VIN as a determinant of response, 74 and lack of response with single‐treatment PDT for VIN type III 75 . The use of topical PDT as monotherapy for extramammary Paget's disease is controversial as reports are mainly in combination with other therapies; 76 however, clearance of recurrent disease with intralesional ALA and multiple treatments has been shown in one subject 77 .…”

Section: Indications For Topical Photodynamic Therapymentioning

confidence: 99%

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

Morton¹,

et al. 2002

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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.

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Section: Indications For Topical Photodynamic Therapymentioning

confidence: 99%

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

Morton¹,

et al. 2002

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“…The majority of studies conducted thus far on ALA stability have been primarily concerned with ALA dissolved in aqueous solutions. As the applicability of ALA‐based PDT embraces new clinical challenges, such as oral cancer (188) and gynecological neoplasias (189), drug delivery using low‐viscosity aqueous solutions is not an appropriate course of action. Clearly, retention at these sites becomes problematic due to difficulties in keeping solutions in place.…”

Section: Formulation Of Ala‐containing Topical Drug Delivery Systemsmentioning

confidence: 99%

Drug Delivery of Aminolevulinic Acid from Topical Formulations Intended for Photodynamic Therapy^¶

Donnelly

McCarron

Woolfson

2005

Photochem & Photobiology

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Topical photodynamic therapy is used for a variety of malignant and pre‐malignant skin disorders, including Bowen's Disease and Superficial Basal Cell Carcinoma. A haem precursor, typically 5‐aminolevulinic acid (ALA), acting as a prodrug, is absorbed and converted by the haem biosynthetic pathway to photoactive protoprophyrin IX (PpIX), which accumulates preferentially in rapidly dividing cells. Cell destruction occurs when PpIX is activated by an intense light source of appropriate wavelength. Topical delivery of ALA avoids the prolonged photosensitivity reactions associated with systemic administration of photo‐sensitisers but its clinical utility is influenced by the tissue penetration characteristics of the drug, its ease of application and the stability of the active agent in the applied dose. This review, therefore, focuses on drug delivery applications for topical, ALA‐based PDT. Issues considered in detail include physical and chemical enhancement strategies for tissue penetration of ALA and subsequent intracellular accumulation of PpIX, together with formulation strategies and drug delivery design solutions appropriate to various clinical applications. The fundamental aspects of drug diffusion in relation to the physicochemical properties of ALA are reviewed and specific consideration is given to the degradation pathways of ALA in formulated systems that, in turn, influence the design of stable topical formulations.

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“…Addition of ethylene diamine tetra acetic acid 12,15 and antioxidants 16 to ALA solutions has resulted in disappointing improvements in stability. Further, the ever expanding range of potential neoplasias that are being treated with PDT, such as oral cancer 17 and gynaecological neoplasias, 18 has necessitated new approaches for drug delivery to these more challenging sites.…”

Section: Introductionmentioning

confidence: 99%

Stability of 5-aminolevulinic acid in novel non-aqueous gel and patch-type systems intended for topical application

McCarron

Donnelly

Andrews

et al. 2005

Journal of Pharmaceutical Sciences

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Single‐episode photodynamic therapy and vulval intraepithelial neoplasia type III resistant to conventional therapy

Abstract: This small uncontrolled study indicates that, as currently administered, a single episode of topical PDT is not effective in the management of treatment-resistant VIN III.

Cited by 36 publications

References 12 publications

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

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

Drug Delivery of Aminolevulinic Acid from Topical Formulations Intended for Photodynamic Therapy^¶

Stability of 5-aminolevulinic acid in novel non-aqueous gel and patch-type systems intended for topical application

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Single‐episode photodynamic therapy and vulval intraepithelial neoplasia type III resistant to conventional therapy

Abstract: This small uncontrolled study indicates that, as currently administered, a single episode of topical PDT is not effective in the management of treatment-resistant VIN III.

Cited by 36 publications

References 12 publications

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

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

Drug Delivery of Aminolevulinic Acid from Topical Formulations Intended for Photodynamic Therapy¶

Stability of 5-aminolevulinic acid in novel non-aqueous gel and patch-type systems intended for topical application

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Drug Delivery of Aminolevulinic Acid from Topical Formulations Intended for Photodynamic Therapy^¶