Photodynamic therapy (PDT) is a treatment option for several skin cancers.
In particular, PDT can be used for:
PDT can also occasionally be used with caution for thin nodular BCCs. Unfortunately there is a concerning failure rate and recurrence rate and many come to later surgical excision. The same usage and concerns are true when PDT is used for squamous cell carcinoma in situ.
PDT is NOT used to treat:
· Invasive SCCs
· Melanoma of any type
· Keratoacanthoma
What is involved in the treatment?
In Australia there is only one TGA approved version of photodynamic therapy available. This tested and proven product is called "Metvix" and your doctor treating you will organise this cream in advance. The active ingredient is called methyl aminolevulonic acid or MAL. It is very expensive. There are some cheaper alternatives that are not TGA approved. These creams or sprays have a different active ingredient called ALA. The safety and effectiveness of these versions is unknown and ACSCM recommends that these cheaper ALA PDT treatments should not be used.
The PDT treatment takes place at the doctor’s surgery. The Metvix cream is applied to the tumour and then covered with a dressing. The patient then waits a few hours for the light sensitizing Metvix to have effect. The patient then has the treatment area subjected to a specific red and / or blue light beam for a specified accurate length of time.
The skin surface needs to be exposed to the air at the time. That is for PDT to work, the cream and the light and air are all needed.
A repeat treatment is organized 7 to 14 days later.
When PDT is used for actinic keratoses often an area rather than a specific lesion is being treated. The Metvix cream is applied to larger area such as part or all of the face. Then the light is applied to this larger area.
Does it work?
PDT is a real alternative treatment for intraepidermal carcinoma, superficial BCCs and actinic keratoses. It is mostly unsatisfactory for other skin cancers. Even when it is used for the correct skin cancers there is a variable number of cases that do not respond to treatment or recur.
As such, follow up appointments are essential following PDT. At the follow up appointment, the doctor will look for any signs of recurrence or persistence of the tumour. If PDT has not completely eradicated the tumour surgery is usually required.
Cost?
PDT is expensive and Medicare does not cover the treatment cost. Pharmaceutical benefits offers no assistance either. Treatment can lead to an out of pocket expense of many hundreds of dollars. The cream and the doctor’s equipment are both very expensive. For this reason, patients often elect to have alternate treatments that are covered by Medicare or by pharmaceutical benefits.
Side effects?
These can be a problem. It hurts when the light is shining on the skin. Some patients can't tolerate it. Once the treatment is over, the area can be very red and weepy until it recovers. The "hip pocket" side effect is often the one that is greatest concern to patients.
Talk to your doctor about PDT and whether it is right for you and your tumour.