Photodynamic therapy for cancer
Definition
Photodynamic therapy (PDT) uses a medicine together with a special type of light to kill cancer cells.
How Photodynamic Therapy Works
First, the health care provider injects a medicine that is absorbed by cells all over the body. The medicine stays in cancer cells longer than it stays in normal, healthy cells.
After 1 to 3 days, the medicine is gone from the healthy cells, but remains in the cancer cells. Then, the provider directs light at the cancer cells using a laser or other light source. The light triggers the medicine to produce a type of oxygen that treats cancer by:
The light can come from a laser or other source. The light is often applied through a thin, lighted tube that is put inside the body. Small fibers at the end of the tube direct the light at the cancer cells. PDT treats cancer in the:
Providers use light-emitting diodes (LEDs) to treat skin cancers. Medicine is placed on the skin, and the light is shone on the skin.
Another type of PDT uses a machine to collect a person's blood, which is then treated with a medicine and exposed to light. Then, the blood is returned to the person. This is used to treat symptoms of a certain type of lymphoma.
Pros and Cons of PDT
PDT has several benefits. For example, it:
But PDT also has drawbacks. It can only treat areas where light can reach. That means it can only be used to treat cancer on or just under the skin, or in the linings of some organs. Also, it cannot be used in people with certain blood diseases.
Side Effects of PDT
There are two main side effects of PDT. One is a reaction caused by light that makes the skin swollen, sunburned, or blistered after just a few minutes in the sun or near bright lights. This reaction can last as long as 3 months after treatment. To avoid it:
The other main side effect is swelling, which may cause pain or trouble breathing or swallowing. These depend on the area that is treated. The side effects are temporary.
References
American Cancer Society website. Getting photodynamic therapy. www.cancer.org/treatment/treatments-and-side-effects/treatment-types/radiation/photodynamic-therapy.html. Updated November 19, 2021. Accessed April 2, 2024.
Lui H, Kalia S. Photodynamic therapy. In: Bolognia JL, Schaffer JV, Cerroni L, eds. Dermatology. 5th ed. Philadelphia, PA: Elsevier; 2025:chap 135.
National Cancer Institute website. Photodynamic therapy to treat cancer. www.cancer.gov/about-cancer/treatment/types/photodynamic-therapy. Updated June 21, 2021. Accessed April 2, 2024.
Review Date: 12/31/2023
Reviewed By: Todd Gersten, MD, Hematology/Oncology, Florida Cancer Specialists & Research Institute, Wellington, FL. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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