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Photodynamic Therapy (PDT) for Cancer

PDT is a treatment that uses medicines called photosynthesizing agents and light to destroy cancer cells. It is most often used to treat certain cancers in the esophagus, lungs, and skin. It can also be used to treat certain conditions that can lead to cancer. This sheet tells you more about PDT and what to expect.

How PDT works

With PDT, you’re given a photosynthesizing agent to treat your cancer. The medicine is absorbed by the body’s cells. It remains longer in cancer cells than in normal cells. When exposed to a laser or other light source of specific wavelength, the medicine is activated. This causes a chemical reaction that destroys the cells. The light source is directed at cancer cells, so there is little damage to normal cells.

Possible side effects of PDT

The main side effect of PDT is sensitivity to light. This occurs because the medicine can stay in the body’s cells for some time after the treatment. To help prevent a reaction after the treatment, you may be advised to avoid bright lights and direct sunlight for one or more weeks. How long this is needed depends on the type of photosynthesizing agent used. Other side effects of PDT depend on the part of the body being treated. For instance, if the esophagus or lungs were treated, shortness of breath or pain when swallowing may occur. If the skin was treated, redness, swelling, or blistering may occur. These side effects go away soon after treatment. Your doctor can tell you more about what side effects to expect and how to manage them.

Having PDT treatment

PDT is done over one or more visits. Before the treatment, your doctor will go over the exact type of medicine that will be used and how it will be given. Your doctor will also go over your treatment schedule with you. The treatment is done in stages.

  • In the first stage, the medicine is put into a vein and sent into the bloodstream. Or, the medicine is applied on the skin over the cancer site. The medicine is then given time to be absorbed by the cancer cells. This may take from a few hours to a few days.

  • In the second stage, a light source is directed at the cancer site. To treat cancer cells inside the body, a scope and fiberoptic cables may be used. These are tools that can be safely passed into the body to deliver light to the cancer site. To treat cancer cells on or just under the skin, the light source is shone directly on the site. This is often done using a lamp or machine.

When to call your healthcare provider 

Call the doctor if you have any of the following:

  • Fever of 100.4 ºF (38 ºC) or higher, or as directed by your healthcare provider

  • Severe shortness of breath or trouble breathing

  • Severe trouble swallowing or pain when swallowing

  • Uncontrolled nausea and vomiting

  • Coughing up of blood

  • Severe redness, swelling, or skin breakdown or severe pain due to skin irritation

  • Any new symptom, or one that causes concern

Follow-up care

You’ll have one or more follow-up visits with your doctor. These allow your doctor to check your health and response to the treatment. If more tests or treatments are needed, your doctor will discuss these with you.

© 2000-2017 The StayWell Company, LLC. 780 Township Line Road, Yardley, PA 19067. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.