Photodynamic Therapy
As the days pass by, new techniques and procedures are being researched for the treatment of cancer, thus giving hope to those who have cancer. Recently, a new therapy was discovered and it is known as photodynamic therapy (PDT). This is a therapy that combines a drug called photosensitizer or photosensitizing agent and a particular type of light. It is the treatment with drugs that becomes active when they are exposed to light, thus when they are activated the drugs may kill cancer cells.
When these photosensitizers are exposed to a specific type of wavelength of light they tend to produce a form of oxygen which in turn kills nearby cancerous cells. So, because the wavelength determines how far the light can travel into the body, specific photosensitizers and wavelength of lights are used to treat different parts of the body. There are three ways of using this PDT for the treatment of cancer. The first is using it directly. There are steps involved in the using of PDT for treatment of cancer. Firstly, a photosensitizer is injected into the bloodstream. The photosensitizer is then absorbed by cells all over the body but the duration of time it stays in cancer cells is longer than that of normal cells. After about approximately 24 to 72 hours, the tumor cells are exposed to light when most of the photosensitizing agent must have left the normal cells. When this happens, the photosensitizer that is present in the tumor cells are absorbs the light and thereby, producing active oxygen that destroys nearby cancerous cells.
Aside from killing cancer directly, the therapy offers other ways which include shrinking or destroying tumor cells. Damaged blood vessels prevent the cancer cells from receiving necessary nutrients, activating the immune system to attack the tumor cells. Well, to be clear about the light that is used for PDT, it can be light from laser or other sources of light. The laser light is directed through fiber optic cables to help deliver light to tissues or areas inside body cavity. Light Emitting Diode (LEDs) is another light source that is used for PDT. Here, the light may be used for surface tumors. PDT can be used in combination with other therapies like surgery, radiation or chemotherapy and usually, it is performed as an outpatient (a patient who is not hospitalized overnight but visits the clinic) or ambulatory patient procedure.
In some cases where laser therapy is less satisfactory, PDT is used. An agent of PDT called Porfium Sodium is used to treat or relieve symptoms of esophageal cancer and non- small lung cancer. This Porfium sodium (or photoforin) is also used for the treatment of precancerous lesions in patients. Although this therapy seems to be the answer, it still has its limitations. PDT is mostly used to treat tumors that are on or just below the skin or on the lining of internal organs because the light needed to activate most photosensitizer agents cannot pass through more than about 1CENTIMETER. So it means that it cannot be used for treatment of already invasive cancer.
After you must have undergone this procedure, you are advised to avoid direct sunlight for about six weeks because Porfium sodium makes the skin and eyes sensitive to light for about 6 weeks after treatment. Due to the fact that when this agent is being activated by light and reaches both normal cells, there is minimal damage to healthy tissues. There could be painful breathing, swelling or scarring of the nearby tissues after treatment.
Since researchers discovered that this therapy is useful for some cancers, it means they should be on their way looking for ways of improving the effectiveness of PDT so that it can be used for treatment of other types of cancer.
Lucy Akabogu
