This is a new form of PDT and has been utilised at SPSSCC since 2015.
With NL-PDT, it is sunlight that activates the ALA Cream (same cream as in traditional PDT). Exactly the same conditions are treated as with traditional PDT, except that typically large areas, or whole skin fields, are treated eg entire face or scalp, entire forearm and hand.
The same treatment reaction occurs.
What happens on the day of treatment?
- Intially the Doctor will mark out the area to be treated and the Nurse will gently curette (scrape) the surface of the skin lesion (s).
- A special sunscreen is applied to the area to be treated (so that the patient does not get sunburnt when being exposed to sunlight)
- ALA Cream is then applied by the nurse and NOT occluded.
- The patient waits inside for 30 minutes to allow the ALA to absorb into the skin.
- The patient proceeds outside and sits for 2 hours. They can sit in the shade as plenty of UV will reach the skin. (Typically this treatment is performed from April/May until October/November when ambient temperatures are not too hot).
- During treatment minor pain is experienced.
- The patient returns to the nurse after 2 hours and an emollient cream is applied.
What happens after treatment?
- Because the area treated is large there is typically much more local reaction than with traditional PDT treatment.
- Pain is usually mild and simple analgesia will suffice.
- A small percentage of patients do experience more intense pain requiring stronger analgesia.
- The treated area becomes intensely red (like a severe sunburn), swollen (especially on the face), blisters and scabs.
- Typically, the treated area peels over 7-10 days.
- As with traditional PDT, it is best to avoid any further sunlight for the remainder of the day.
How many treatments are required?
Typically a single treatment is adequate for the face, although a series of treatments may be necessary for the scalp and limbs.
Medications may affect this treatment
As with Traditional PDT, these include Doxycycline, Thiazides, Griseofulvin, Sulphonylurea, Phenothiazines.
As with any treatment, it is essential to inform the Doctor of all current medications and illnesses.
Advantages of NL-PDT
- As per all the advantages of Traditional PDT
- Large areas can be treated in a single episode of treatment.
- Much less pain than traditional PDT treatment of large areas.
Disadvantages of NL-PDT
- As per all the disadvantages of Traditional PDT.
- More extensive and severe skin reactions due to the larger areas being treated.
- Cannot be performed in very cloudy and/or rainy weather.
- Cannot be performed during the warmer months of the year.
It is critical therefore, that NL-PDT is only used in centres with significant experience with the particular modality of PDT. The seasonal timing of the treatment is also important.