Photodynamic Therapy (PDT)

Independent dermatologists consulting from Eastern Suburbs Dermatology offer photodynamic therapy, where appropriate, for certain types of non-melanoma skin cancer and pre-cancerous skin lesions. Please note that not all types of skin cancer are suitable for this form of treatment and currently there is no government Medicare rebate for this procedure. Veterans’ Affairs may approve this treatment on individual application by your doctor. The cost of treatment depends upon the size of the lesion.

PDT or photodynamic therapy is the application of a cream (which contains a photoactive chemical that is more selectively absorbed by abnormal cells in comparison to normal tissue) to the lesion to be treated. The chemical in the cream is then activated by exposure to a specific wavelength of light which destroys the abnormal cells leaving normal tissue unaffected.

What skin lesions are suitable for photodynamic therapy?

Your dermatologist will advise if your skin lesion is suitable for PDT and what alternative treatments are available. In most cases a skin biopsy is required to confirm the exact diagnosis prior to treatment.

What is the treatment procedure for photodynamic therapy?

With photodynamic therapy, one or more lesions can be treated at the same time. In most cases, the treatment protocol consists of 3 steps:

  • Lesion preparation: to better assist absorption of the active chemical, the surface of the lesion is gently scraped to remove dead skin, crust or similar.
  • Cream application: The photoactive cream is applied to the lesion and surrounding skin, which is then covered with a dressing that must be left intact for at least three hours. The area must not be exposed to sunlight or very cold air. During this time you are free to leave the clinic.
  • Light source exposure: the dressing and excess cream is removed prior to exposure to the red light source. The exposure time is normally less than 10 minutes. Only the abnormal tissue which has absorbed the chemical reacts to the light. The normal, healthy skin is unaffected. However as the light source is very intense, you will be given protective goggles to wear in order to protect your eyes.

For skin cancers, a second cycle of treatment is routinely repeated one week later.

Is photodynamic therapy painful?

This varies from patient to patient and the location of lesions to be treated. If pain is experienced, it can have a stinging or burning quality. Discomfort can be minimised by taking painkillers such as paracetamol two hours before illumination. If required, the light exposure can be paused (with no adverse effect on the final outcome), so that additional pain relief such as a local anaesthetic can be given.

Cosmetic results

The selective destruction of abnormal cells only by PDT means that the scarring potential of PDT is less likely in comparison to other methods of skin cancer treatment. It is, however, important to remember that the ‘gold standard’ for skin cancer treatment is still surgical removal. The studies using PDT suggest a success rate around 70% in non-melanoma skin cancer treatment.

Photodynamic therapy aftercare

After completing your cycle of PDT, keep the area clean and avoid direct sunlight exposure of the treated area for two days. The most common side effect immediately following treatment is local discomfort which should be readily relieved with paracetamol.

  • The treated site will normally become red, swollen and crusted and may or may not have a weeping discharge.
  • The site should be bathed with salty water twice a day followed by the application of surgical spirit, iodine solution, antibiotic ointments or vaseline. Your specialist will advise on the best course of aftercare for you.
  • Once a dry crust has formed, the area should be left alone and a moisturiser applied once the crust has lifted. Please contact your  dermatologist  or  call  Reception if you have concerns about the treatment.

Daylight photodynamic therapy

This is a more recent application for PDT, specifically for the treatment of extensive solar keratosis (field therapy). A result of studies carried out both in Australia and Europe have shown that the active cream can be applied very thinly to the areas to be treated. After allowing ½ an hour for the cream to be absorbed, your dermatologist will ask you to expose the area of treatment to sunlight (this activates the chemical just like the red light does – but the activation is much more gentle and is virtually pain free) for a period of 2 hours. After which the residual chemical is removed by your dermatologist and red light illumination is given to activate any remaining chemical.

The end reaction is like a moderate sunburn – peaking in severity 2-3 days after treatment, usually by the end of one week most of the peeling is complete. Clearance of 60-70% of sunspots can be expected. This treatment is an option for patients who do not want to use other topical agents including liquid nitrogen cryotherapy, and other topical treatments that are currently available. You can discuss all these treatment options with your dermatologist.

experts in skincare

Dermatologists consulting from Eastern Suburbs Dermatology provide consultative and procedural services are all Fellows of the Australasian College of Dermatologists.

Practising individual dermatologists consulting from Eastern Suburbs Dermatology have sub-specialisation interests in paediatric dermatology, surgical dermatology, and women’s and cosmetic dermatology.