Photodynamic therapy - PDT

Combination of a photosensitizer and illumination of the lesion with light, resulting in photodamage and subsequent cell death.

PDT is used in the treatment of actinic keratosis, skin cancer, acne, psoriasis.

Water-filtered infrared A has been shown to be associated with reduced pain in comparison to activation with LED light.

Mechanism of action Methyl aminolevulinate and 5-aminolevulinic acid

are antineoplastic agents. After topical application, porphyrins will accumulate

preferentially intracelluarly in the skin lesions. Light activation of accumulated porphyrins leads to a

photochemical reaction causing phototoxicity to the light exposed target cells.

Castano et al. Nature Reviews Cancer 6, 535–545 (July 2006) | doi:10.1038/nrc1894

Treatment 5-aminolevulinic acid (5-

ALA, Metvix®) photosensitizer.

Image 1: Demarcation of the area to be treated

Image 2: Application of 5-ALA cream

Image 3: Directly after application of hydrosun 750 infrared irradiation

Image 4: Four days post-treatment

Indications: Metvix, Galderma

Thin or nonhyperkeratotic, nonpigmented actinic keratoses (AK) of face, scalp when other therapies unacceptable

Primary treatment of superficial and/or nodular basal cell carcinoma (BCC) where surgery is inappropriate

Primary treatment of biopsy proven squamous cell carcinoma (SCC) in situ (Bowen's disease), where surgery is inappropriate

Common light sourcesAktilite Omnilux

Contraindications Morpheaform basal cell carcinoma (BCC) Invasive squamous cell carcionoma (SCC) of the skin Porphyria Peanut oil hypersensitivity

Precautions Avoid direct eye contact; UV therapy, sun exposure; renal,

hepatic impairment Monitor for recurrence every 6-12 months Pregnancy, lactation (within 48 hours), children < 18 yrs AK: previous 5-FU, tretinoin treatment; pigmented, highly

infiltrating, thick (hyperkeratotic), recurrent lesion BCC: recurrent lesion; BCC associated xeroderma

pigmentosum, Gorlin's syndrome, immunosuppressive therapy.

SCC in situ: genital, pigmented, highly infiltrating, recurrent, > 40 mm diameter lesion

Adverse effects Local reaction eg pain, burning, stinging, prickling,

tingling, bleeding skin; eczema Allergic contact dermatitis; swelling; erythema;

itching; oedema; crusting; ulceration; blister; suppuration; infection; peeling

Hypo/hyperpigmentation; rash, headache, nausea, eye pain, irritation, fatigue, dizziness (uncommon)

Method of administration Preparation of the lesions:

Scales and crusts should be removed before administration of Metvix.

All lesion surfaces should be roughened gently. Care should be taken to avoid bleeding. Thereafter, all lesions should be carefully wiped-off

with an ethanol or isopropanol-soaked cotton pad to ascertain degreasing of the skin.

Application of the gel Metvix should be applied to the entire lesion area

using glove protected fingertips or a spatula. Direct contact of Metvix with the eyes or mucous

membrane should be avoided. The gel can be administered to healthy skin around

the lesions, whereas application near the eyes, nostrils, mouth, ears or mucosa should be avoided (keep a distance of 1 cm).

Application of the gel The gel should cover the lesions and approximately 5

mm of the surrounding area with a film of about 1 mm thickness.

The gel should be allowed to dry for approximately 10 minutes, before an occlusive light-tight dressing is placed over the treatment site.

Following 3 hours of incubation, the dressing should be removed and the remnant gel wiped off.

Illumination Immediately after cleaning the lesions, the entire

treatment area should be illuminated with the light source.

During illumination the lamp should be fixed at a distance from the skin surface of 27-30 cm.

The entire treatment area should be illuminated with the hydrosun 750 for 15-20 minutes.

The irradiation time for more sensitive areas can be reduced to 10–15 minutes.

Sessions Actinic keratosis (solar keratosis)

One session. If not completely cleared 12 weeks after initial

treatment, lesions can be treated a second time with an identical regimen.

Basal cell carcinoma and Squamous cell carcinoma in situ (Bowen's disease) Two sessions at weekly intervals; retreat in 3 months if necessary.

Solid basaliomaSolid basalioma prior to

PDT Healing 5 months after second PDT treatment

Fluorescence diagnosis with handheld torch

Dermabrasion

Hobart Case Report - AK ALA 20% solution Australian Customs Pharmaceuticals, Sydney $90 for 5ml Treatment provided by Dr Ian Hoyle, Hobart Treating patients with generalised solar damage:

good results, less pain than when using LED light

Aktinic keratosis

Applying ALA (5-aminolevulinic acid)

Activation of ALA with Hydrosun 750 water-filtered

infrared A lamp

AK nose: day after treatmentHealed completely in 7 days