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 stays longer in cancer cells than in normal cells. When exposed to a laser or other light source of specific wavelength, the medicine starts to work. 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 most common side effect of PDT is that the skin and eyes become sensitive to light. This occurs because the medicine can stay in the body’s cells for some time after the treatment. When you are exposed to sunlight or other forms of bright light, the skin can quickly become swollen, sunburned, and blistered. To help avoid a reaction after the treatment, you may be told to avoid bright lights and direct sunlight for at least six 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 healthcare provider 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 healthcare provider will go over the exact type of medicine that will be used and how it will be given. He or she 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 for the cancer cells to absorb it. 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 your healthcare provider 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 healthcare provider. At these visits, your healthcare provider checks your health and response to the treatment. If more tests or treatments are needed, your healthcare provider will discuss these with you.