Daylight Photodynamic therapy

In cases of non-melanoma skin cancer in which surgery is not considered appropriate, topical treatments such as imiquimod, 5-fluorouracil or photodynamic therapy (PDT) may be used.

These have the benefit of treating large areas of clinically visible and subclinical lesions with minimal residual scarring.

PDT involves applying a special light-reactive cream (Metvix in South Africa) to precancerous lesions after which the area is exposed to a particular type of light for a short time. This light activates the topical cream to selectively damage the cancerous and precancerous cells.

Natural or daylight PDT is based on the same principal as conventional PDT, but instead of being performed in a dermatology practice using an indoor light source, it is performed by the patient at home using daylight to activate Metvix. Before treatment is started a sunscreen with a SPF of 30 or higher is applied to the treatment area. This will protect your skin from the ultraviolet rays but will not block the daylight. Metvix is applied 20 minutes after the sunscreen and half an hour later you will be required to have two hours of daylight exposure. This is done in the shade and not in full sunlight. There may be mild tingling or pain in the treated area of skin during and after treatment. You may need a second session a week later depending on the area treated. Follow up treatment is required to assess the outcome of your treatment. Recent European studies show that daylight PDT is as effective as conventional PDT in the treatment of actinic keratoses, Bowen’s disease and superficial basal cell carcinoma and generally better tolerated by patients.