Photodynamic Therapy

What is photodynamic therapy?

Photodynamic therapy (PDT) is a treatment that uses a light and photosensitizing agents to kill skin cancer cells. The drugs only work after they have been activated or “turned on” by certain kinds of light. The agent is applied to the skin and then there is a waiting period of a couple of hours before the light can be used with the drug for the treatment.  

Pros and cons of PDT

  • It’s less invasive than surgery.
  • It usually takes only a short time with treatments of areas up to 20 minutes per area treated
  • It can be targeted very precisely such as arms, face, scalp
  • PDT can be repeated many times at the same site if needed.
  • There’s usually little or no scarring after the site heals.
  • It often costs less than other cancer treatments.
  • PDT can only treat areas where light can reach.
  • PDT can’t be used to treat cancers that have spread to many places.
  • The drugs used for PDT leave people very sensitive to light for some time, so special precautions must be taken after the agents are used on the body.

Uses and side effects of specific PDT drugs

What is treatment like?

Aminolevulinic acid (Levulan Kerastick) is a solution that’s used directly on the lesions of actinic keratosis. The drug is left on the affected skin for about 2-4 hours. After incubation, the exposed areas or lesions will be treated by a blue light for about 15 minutes. During the light therapy you will be required to wear protective eyewear. You may feel stinging or burning once the area is exposed to the blue light, but it should go away within a day or so.  The treated area will get red and scaly and can crust for up to 4 weeks after treatment before healing.  If a lesion does not completely go away after treatment, it can be treated again 8 weeks later.

Who should not get treated with aminolevulinic acid?

Aminolevulinic acid is NOT recommended for people with skin sensitivity to blue light, people with porphyria, or anyone with an allergy to porphyrins.

Possible side effects

Photosensitivity reactions:

  • Stay out of strong, direct light.
  • Stay indoors as much as possible.
  • Wear protective clothing and wide-brimmed hats to avoid sunlight when outdoors.
  • Avoid beaches, snow, light colored concrete, or other surfaces where strong light may be reflected.
  • Sunscreens will not protect the skin from photosensitivity reactions.
  • Skin changes: The treated areas will likely turn red and may swell after treatment. It can become red and scaly  but should be gone about 4 weeks after treatment. The skin may also be itchy or change color after treatment.

Talk with our dermatologists about what you should expect your treated skin to look and feel like.