PDT (photodynamic therapy) is used in a number of different cancer therapies – including the treatment of squamous cell lesions on the skin. This therapy has been shown to be particularly useful for patients who have not responded to other treatments and for those with recurring tumors.
In one small study of 30 patients, 72% experienced excellent response to the light therapy. At the 3 year follow up, 64% of these individuals remained cancer free with no recurrence of their head or neck skin tumors. There were 5 patients who stopped participating in the study after an initial adverse reaction to the PDT therapy. They reported pain or burning sensations as a result of the light exposure. So, this treatment may not be suitable for all skin cancer patients. Or, the type of PDT therapy may need to be adjusted for patients who have this type of side effect.
Comparative Study Shows Outcomes Best with MAL-PDT
MAL-PDT (which pairs light therapy with a photosensitizing cream called methyl aminolevulinate) has been compared in a large study with cryotherapy and chemotherapy for squamous cell tumors. Cryotherapy involves freezing off the cancerous lesions with liquid nitrogen. Topical 5-flourouracil is a chemotherapy drug used to treat skin cancer on an outpatient basis. These two treatments were compared with MAL-PDT to determine both effectiveness and cosmetic results.
At the 12 month mark, the outcomes were reviewed for all patients. Those who received the MAL-PDT treatment had a complete response rate of 80%. This means the treated skin tumor was successfully eradicated for most of these patients. The rate of complete response for cryotherapy was 67% and 69% for 5-flourouracil.
The appearance of the skin in the area of the lesion was rated good or excellent for almost all of the patients treated with photodynamic therapy (94%). Cryotherapy patients had the worst cosmetic outcome. Only 66% of patients who had their tumors frozen off experienced good or excellent results. 5-flourouracil patient results were somewhat better at 76%.
Reasons Patients May Prefer PDT
Treatment with PDT is non-invasive. It can be somewhat time-consuming since the photosensitizing drug must be applied several hours prior to the actual light therapy session. However, it usually doesn’t take very many sessions to successfully treat a lesion. So, the overall time invested may be less than that spent applying a chemotherapy cream every day for a period of several months. Light therapy causes less injury to the skin than cryotherapy which may make it more appealing to patients who are adverse to any type of surgery.