What Is Photodynamic Therapy?
To kill cancer cells, photodynamic therapy uses a medication called a photosensitizer or photosensitizing agent that is activated by light. A laser or other light source, such as LEDs, can be used to produce light. PDT stands for photodynamic treatment.
Photodynamic therapy is most commonly utilized as a local treatment, meaning it only affects a small area of the body.
Cancer and Precancers Treated with Photodynamic Therapy
The FDA has approved PDT to treat:
- actinic keratosis
- advanced cutaneous T-cell lymphoma
- Barret’s esophagus
- basal cell skin cancer
- esophageal (throat) cancer
- non-small cell lung cancer
- squamous cell skin cancer (stage 0)
Photodynamic therapy is also used to relieve symptoms of some cancers, including:
- esphageal cancer when it blocks the throat
- non-small cell lung cancer when it blocks the airways
How PDT Treats Cancer
When cells that have been treated to photosensitizers are subjected to a specific wavelength of light, the photosensitizer creates an oxygen radical, which kills the cells.
Photodynamic therapy may damage the tumor’s blood arteries, preventing it from receiving the blood it requires to grow. It also has the potential to cause the immune system to fight tumor cells in other parts of the body.
Drawbacks of DPT
Photodynamic therapy can induce negative effects by harming normal cells in the treatment area.
Photodynamic treatment light can only pass through about a third of an inch of tissue, or one centimeter. As a result, photodynamic treatment can only be used to treat tumors on or just beneath the skin, as well as those on the lining of internal organs or cavities.
Photodynamic treatment is less effective in treating big tumors since the light can’t penetrate very far.
Side Effects of PDT
Although photodynamic therapy causes minimal damage to normal cells, it can nonetheless result in burns, swelling, discomfort, and scarring in the treatment area. Other side effects, depending on the location being treated, may include:
- trouble swallowing
- stomach pain
- painful breathing
- shortness of breath
- skin problems, such as redness, stinging, swelling, or itching
For around 6 weeks, a form of photosensitizer called porfimer sodium makes the skin and eyes sensitive to light. Avoid direct sunlight and bright indoor lighting during this period.
ECP can cause:
- brief periods of low blood pressure
- faster than normal heart rate
- low blood platelet count
Side effects improve once treatment is over.