Treatment of cancer with light sensitive drugs is popularly known as “Photodynamic therapy of Cancer” abbreviated as PDT.
In this therapy, a type of drug, that has the ability of activation on exposure to particular type of light, is given to the patient (mostly in the form of injection) of cancer and then the body is exposed to that particular light so that the light activates the drug and start killing the cancer cells.
These drugs are also known as “Photosensitizing agents” or “Photosensitizers”. These drugs start producing a particular form of oxygen that can kill cancer cells.
Moreover, a specific wavelength of light (i.e. laser light) is used that has the ability of penetrating into the body.
Mechanisms of cancer killing through photodynamic therapy:
With the help of photodynamic therapy
1. cancer cells are directly killed or
2. the neighbouring blood vessels are damaged so that the tumor cells may not receive the necessary nutrients or
3. the immune system may be activated
or all these processes may occur.
It may cause swelling, pain or burning sensation. It may also result in coughing and painful breathing, stomach pain and trouble swallowing.
Example of Photosensitizing agent:
U. S. Food and Drug administration (FDA) has approved porfimer sodium, or Photofrin®. It is a photosensitizing agent and is used for the photodynamic therapy of esophageal cancer and non-small cell lung cancer.
References and Further Reading:
Agostinis, P. et. al. (2011). Photodynamic therapy of cancer: An update. CA: A Cancer Journal of Clinicians, 61(4), 250-281.
Dolmans, et. al. (2003). Photodynamic therapy for cancer. Nature Reviews Cancer, 3, 380-387.
http://www.cancer.gov/cancertopics/factsheet/Therapy/photodynamic accessed July 12, 2011.