What is Photodynamic therapy?
Photodynamic therapy (PDT) is a technique used for the treatment of various skin cancers. The technique has largely replaced liquid nitrogen therapy for extensive sun damage in most modern dermatology clinics. The treatment involves the application of a light sensitising cream to the treatment area and the subsequent exposure of that area to light.
Which skin cancers can be treated by Photodynamic therapy?
Photodynamic therapy (PDT) is used for the treatment of Solar Keratosis, Basal Cell Carcinomas, and Bowens disease.
Is photodynamic therapy still an experimental treatment?
No, photodynamic therapy has been used since 1988 and have been extensively investigated and subjected to many clinical trials. Look at the PUBMED medical database for the available published research on PDT.
How is the treatment done?
Rough spots in the treatment area are lightly scraped and a cream is then applied over the whole treatment area. The cream is left on for 1-3 hours. During this time you may leave the surgery, but most of our patients choose to stay in the clinic. After 1-3 hours the excess cream is wiped off and the area is exposed to a specific light source for 20 minutes. If the lesion is a basal cell carcinoma the procedure is repeated after 7 days.
After the cream is applied the cancerous cells absorb the cream while the normal skin cells do not. The cream is converted inside the cancerous cell to a chemical that is extremely sensitive to red and blue light. After 1-3 hours the chemical is, for practical purposes, only present in cancerous cells and not present in normal skin cells. When the red or blue light is shone on the skin the chemical becomes activated and free radicals are formed inside the cancer cells. These free radicals then kill the cancer cells.
What does the treatment feel like?
It depends on how long the cream was left on the skin and what type of pain relief you have. If the cream is left on for about and hour, no pain relief is generally necessary. Most patients describe the pain at around a 4-6/10, with 10/10 being very painful and 0/10 no pain.
If the cream is left on for about 2 hours an oral analgesic can be used for pain relief.
If the cream is left on for more than 2 hours conscious sedation or other pain relief techniques can be used.
The size of the area that needs to be treated also influences the degree of discomfort. If a small area is treated the treatment is done under local anaesthetic and therefore painless.
What are the side effects following treatment?
Very common side effects are a burning sensation, stinging sensation, pain, swelling, crusting and redness. Less common side effects include itchiness, ulceration, suppuration, blisters, peeling, skin infection, hyperpigmentation and hypopigmentation. Urticaria is a rare side-effect.
What are the advantages of PDT over other treatments?
PDT destroys only cancerous cells and not normal cells. It is therefore selective and scarring is extremely unlikely. Liquid nitrogen therapy, surgery and curettage & cautery have a significant risk of scarring. Liquid nitrogen therapy very often leaves white spots following treatment. With PDT these side-effects are much less likely. PDT also results in significant skin texture improvement and has a general rejuvenating effect in the treatment area.
How effective is Photodynamic therapy compared to other treatments?
Clinical cure rates of Photodynamic therapy is similar to all the other treatment options, but has significant cosmetic advantages and does not affect normal cells.
What are the medical aid codes in South Africa for the treatment?
0191, 0202, 0286, Nappi code: 700004001
What does the treatment cost?
It depends on the size of the involved area, but generally between R1500 and R2100. Conscious sedation, if used, adds to the cost of the treatment.
What happens when I arrive at the surgery for photodynamic therapy treatment?
- The area to be treated will be lightly scraped with a curette and wiped with acetone to remove any residue that could inhibit the absorption of the PDT cream.
- The PDT cream will then be applied.
- The cream will be left in place for 1 – 3 hours.
- Depending on how long the cream is left on, you will either stay in the practice or leave the practice, but should completely avoid all sun exposure.
What happens after the PDT cream is removed?
- The light will be positioned over the area that needs treatment and you will then be exposed to a red or blue light source for 9 minutes.
- During the treatment you will experience a burning sensation. The longer the cream was left on, the more intense the pain will be.
- The burning sensation tends to build up over 3-5 minutes, then plato and after 5-7 minutes it starts to diminish.
- Another 1 or 2 treatments might be required at 4-6 week intervals, to achieve optimal results.
What happens after the treatment has been completed?
DAY 0-2 after treatment:
- The treated area will feel hot and burning for 3-24 hours.
- Cold compresses and analgesics will help to relieve the sensation.
- You will also experience a varying degree of pain in the treated area that can be relieved by taking Paracetamol (e.g. Panado, Compral) and NSAIDS (e.g. Voltaren, Brufen) 4-6 hourly.
- Forehead treatment can lead to upper eyelid swelling and puffiness.
DAY 2-5 after treatment:
- You will experience crusting, scaling and redness.
- Regular use of Vaseline will help to keep the area smooth and prevent cracking.
By day 7 the area should be nice and smooth, but will be slightly red. Some mild scaling might still be present
- The redness will fade over weeks.
The intensity of these sensations is directly correlated to how badly sun damaged your skin is.
Regular (3 hourly) application of a SPF 30+ sunscreen is essential for at least 6 weeks.