Could light be a treatment for cancer? It is for mesothelioma patients. There is an emerging treatment called Photodynamic Therapy, or PDT, that actually uses light energy to kill cancer cells. It is used in combination with a drug that targets the cells for the light to destroy. Clinical trials have found tremendous success in improving life expectancy when used along with surgery and other traditional treatments.
How it works:
The PDT process begins with the doctor injecting a photosensitizer into the bloodstream that makes all cells sensitive to certain wavelengths of light. Even though healthy cells and cancerous cells both absorb the drug, most of the photosensitizer leaves the healthy cells in three days, but is retained by the mesothelioma cells. This is when the light is applied by a laser or by fiber optic cables inserted into the lungs to directly aim the light at the tumor and cancer cells. The light must be a certain wavelength and color to activate the photosensitizer. This in turn causes the drug to produce a highly reactive form of oxygen the kills any nearby cancer cells and damages the tumor’s blood vessels. Photodynamic therapy is usually an outpatient procedure that takes one hour and does not require a hospital stay.
Who is eligible:
PDT is not suitable for patients with large tumors due to the fact it can only be used on areas of the body that light can reach. It would be unable to penetrate an entire tumor, but it is very effective when treating localized cancer below the skin or along the lining of internal organs.Photofrin is the main photosensitizer used for pleural mesothelioma treatment. It has been approved by the Food and Drug Administration (FDA) for other cancers, but not yet for mesothelioma. The FDA has recognized its potential for treating mesothelioma and therefore designated it an orphan drug to expedite the approval process.
Side effects:
As with all treatments there are some side effects. PDT causes skin and eye sensitivity to light for about six weeks, so patients should avoid sunlight and other bright light during this time. PDT can cause swelling, burning, pain, or scarring in healthy tissues. Patients may also experience trouble swallowing, stomach pain, coughing, painful breathing, or shortness of breath.
Study results:
Photodynamic therapy studies have been most successful in recent years when it was added to surgery, increasing survival by an average of 3 to 4 more months. Prior to 2004 PDT was used in conjunction with surgery and chemotherapy, but showed no significance in survival rates. Medical researchers are encouraged by the more current success rates and concluded PDT shows promise for treating mesothelioma in the future.As research continues, doctors are seeking ways to make the reaction more potent to the tumors and cancerous cells. They also seek more effective ways to administer the light. Cancer treatment hospitals are taking note of PDT, and beginning to see it as an effective tool in fighting mesothelioma.
