Patient & Procedure Details
Site(s) & procedure(s)
What is photodynamic therapy?
Photodynamic therapy (PDT) is a technique used to treat precancerous and cancerous skin lesions. A cream is first applied to the area to be treated and left on for 2-3 hours. This wait is to allow the inactive photosensitiser to be absorbed into the skin and to be converted by skin cells into the active form of the photosensitiser. The cream or gel is then wiped off and the area cleaned. Either a bright light is shone on to the affected area for up to 30 minutes or the area is exposed to natural sunlight for up to 2 hours. There will be some degree of discomfort during this light exposure. Rarely if the discomfort is significant it may be necessary to discontinue the treatment.
The treatment area then needs to be covered to protect it from daylight for the rest of the day to limit inflammation. If it is a small area, a dressing will be applied which is to be kept on, usually for two days to prevent any further exposure to light. If it is a larger area then sunscreen is applied and should avoid sunlight exposure.
Alternatives to photodynamic therapy include doing nothing, topical treatments such as efudix (5-FU) or imiquimod, cryotherapy (freezing) and surgical treatment.
After the treatment there will be inflammation, redness, swelling, crusting and discomfort which will usually resolve within 1-2 weeks.
Contraindications
Allergy to Photosensitizing Agents
The PDT cream may contain peanut oil and it is very important that you inform the clinic if you are allergic to peanuts or soy. You should also inform the clinic if you have an allergy to other components such as porphyrins.
Pregnancy and Breastfeeding
The safety of PDT during pregnancy and breastfeeding hasn't been established so it is not advised.
Photosensitivity Disorders
Conditions that make the skin unusually sensitive to light, such as porphyria, solar urticaria, lupus erythematosus, xeroderma pigmentosum, or polymorphic light eruption, may worsen with PDT.
Use of Certain Medications
Medications that increase sensitivity to light, including certain antibiotics, cancer drugs, and diuretics, may increase the risk of severe side effects with PDT. Inform Dr Lynch if you are taking any medication.
Skin Infections or Inflammation
Active skin infections or conditions causing significant inflammation may be worsened by PDT, so treatment may be postponed.
History of Scarring or Keloids
Patients who have a history of keloid formation or excessive scarring have an increased risk of poor healing or scar formation.
Severe Liver or Kidney Disease
As the photosensitizing agents used in PDT are processed by the liver and kidneys, severe dysfunction in these organs may contraindicate the use of PDT.
Important events
Due to the risks of unsightly changes in appearance of the skin it is not advisable to have treatment shortly before important events such as weddings or important business meetings etc.
Inflammatory skin diseases
Inflammatory skin diseases such as vitiligo, psorisasis or lichen planus: If you suffer from an inflammatory skin disease, inflammation of the skin, for example caused by photodynamic therapy, can cause this to be triggered at the site of treatment. It is essential to inform Dr Lynch so that the risks and benefits of treatment can be discussed.
All treatments carry risks and it is important that you carefully weigh the benefit of photodynamic therapy against these potential risks when deciding whether it is the right treatment for you.
Risks
- Inflammation, redness, swelling, discomfort (common) The most common side effect of PDT is a reaction at the site of treatment, including redness, swelling or bruising. These symptoms typically subside within a few hours to a few days but very rarely may persist or be permanent.
- Pain Some patients experience significant pain and/or a burning or stinging sensation during and after the treatment. The pain is usually localized to the area being treated and can vary in intensity. Rarely the pain may be so severe that treatment cannot be continued.
- Photosensitivity Patients become very sensitive to light for a period after treatment, usually about 48 hours, but this can vary depending on the photosensitizer used. Patients are advised to avoid direct sunlight and bright indoor light for at least 48 hours post-treatment.
- Blisters and Burns In some cases, PDT can cause blistering, peeling, or burns on the treated area. These effects are generally mild and heal over time, but they can be uncomfortable.
- Infection Though rare, there's a risk of infection bacterial or viral (e.g. herpes virus) infection at the treatment site, especially if blisters or open sores develop. You should inform Dr Lynch if you experience recurrent cold sore infections.
- Changes in Skin Color PDT can lead to changes in the skin color of the treated area, resulting in hyperpigmentation (darkening) or hypopigmentation (lightening) of the skin. These changes are usually temporary but can be permanent in some cases.
- Scarring There's a small risk of scarring from the treatment, particularly if the treated area becomes infected or if there's an excessive reaction to the light therapy. Rarely there may be unsightly, lumpy or keloid scarring.
- Hair loss or increased hair growth There may be hair loss at the site of treatment. This is usually temporary but may be permanent. In some cases there can be increased hair growth at the treated site.
- Eye Damage If the eyes are not properly protected during the treatment, there's a risk of damage to the eyes from the light source.
- Allergic Reaction Although rare, some people may have an allergic reaction to the photosensitizing agent used in PDT, other components of the cream or dressings used.
- Failure to Achieve Desired Results or recurrence of the condition PDT may not be effective in treating the targeted condition or may be initially sucessful but the problem may subsequently recur.
Additional risks / discussion
Aftercare
Please read the aftercare instructions in detail. It is particularly important to protect the treated area from exposure to sun or bright light after the treatment is complete.
Confirmation & consent
By signing below, I confirm that I have read the above information and had adequate time to decide about my care. I confirm the site(s) and procedure(s) and have had the opportunity to ask questions about the treatment and alternatives. I have been provided with aftercare instructions. I consent to the above procedure(s) and to photographs being taken for my confidential medical record.
This document is an electronic record of consent.