Photodynamic therapy (PDT) is an FDA approved laser treatment that involves injecting photosensitizing chemicals into the bloodstream. Cells throughout the body absorb the chemicals. The chemicals collect and stay longer in the cancer cells, than in the healthy cells. At the right time, when the healthy cells surrounding the tumor may already be relatively free of the chemical, the light of a laser can be focused directly on the tumor. As the cells absorb the light, a chemical reaction destroys the cancer cells. The light is delivered through a endoscope, a small, flexible tube with a light on the end, that is inserted through the mouth or nose. PDT may be used to relieve or reduce symptoms of esophageal cancer, such as difficulty swallowing.
Argon lasers can pass through about an inch of tissue without damaging it, so PDT can be used for the treatment of cancers that are close to the surface of the skin. It can also be directed at cancers that are located in the lining of the internal organs, such as:
In the lungs by using a bronchoscope
In the esophagus and gastrointestinal tract by using an endoscope