Photodynamic therapy for esophageal cancer
Photodynamic therapy (PDT) is sometimes used to treat esophageal cancer. It uses photosensitizer drugs to destroy cancer cells. These drugs make cells sensitive to light. After the photosensitizer is given and has been taken up by the cancer cells, the doctor uses an endoscope to expose the cells to light.
PDT only destroys cancer cells in the inner layer, or mucosa, of the esophagus that can be reached by the light. It can’t be used for esophageal cancer that has spread into deeper layers of the esophagus or to other parts of the body. You may have photodynamic therapy to:
- treat Barrett’s esophagus if you can’t have endoscopic mucosal resection (EMR) or other surgeries
- treat any Barrett’s esophagus or early esophageal cancer (Tis and T1 tumours) left behind after EMR
PDT may also be offered to people with advanced esophageal cancer. It can relieve pain or make swallowing easier (called palliative PDT). PDT may be given along with other treatments, including external beam radiation therapy, laser surgery or surgery to place a stent (for advanced esophageal cancer).
Your healthcare team will consider your personal needs to plan the drugs, doses and schedule for photodynamic therapy. You may also receive other treatments. People who are treated with PDT will need close follow-up after treatment to check if the cancer has returned. The most common follow-up test is an upper gastrointestinal (GI) endoscopy.
How PDT is given
PDT is done in 2 stages. First, you are given the photosensitizer drug. It is injected into a vein. All cells take up the photosensitizer. Over time, it leaves most normal cells, but stays in the cancer cells.
After 48 hours, the doctor uses an endoscope to expose cancer cells containing the photosensitizer to a low-intensity laser light. The photosensitizer in the cancer cells absorbs the light and a chemical reaction occurs that kills the cancer cells. Most normal cells are not affected.
After another 48 hours, the doctor may repeat the procedure to treat the area again with low-intensity laser light.
Special precautions need to be taken because photosensitizers make the skin and eyes sensitive to light. This is called photosensitivity. It usually lasts 4–6 weeks after treatment, but it can last longer.
Clinical trial discovery improves quality of life
A clinical trial led by the Society’s NCIC Clinical Trials group found that men with prostate cancer who are treated with intermittent courses of hormone therapy live as long as those receiving continuous therapy.