Photodynamic therapy or PDT is a fairly new form of treatment used to treat various forms of cancer. The treatment involves utilizing various photosensitizing agents along with differing wavelengths of light to destroy the cancer cells.
In order to determine which type of PDT to utilize the type of cancer involved is primary. This is because the various light waves utilized differ in their ability to penetrate into the body. Different photosensitizing agents will also be used which are injected first into the bloodstream.
These agents will remain in the cancer cells after they are gone from the normal cells, a procedure which usually takes anywhere from 24 to 72 hours depending upon the photosensitizing agent. There are currently three PDT photosensitizing agents approved by the FDA.
Once the appropriate timeframe has passed, the wavelength of light necessary is applied and absorbed by the cancer cells. According to the National Cancer Institute, this produces an “active form of oxygen” which then will destroy the cancer cells.
It can be used just as frequently as any other form of treatment such as radiation, surgery or chemotherapy. When it comes to radiation however, PDT can be utilized repeatedly without the ultimate limitation of lifetime radiation dose.
PDT also kills cancer cells in two additional ways, it can destroy the blood vessels which supply the tumor resulting in cell death and it also stimulates the immune system which can help to destroy the cancer cells as well.
PDT can be utilized within the body to treat areas such as the lungs or esophagus with the use of an endoscope to deliver the light waves which are typically created with a laser and using fiber optic cables for the application. It can also be used to treat areas outside the body utilizing diodes (LEDs) for things such as skin cancer.
The side effects/complications of PDT are far less than those seen with other more severe types of treatment such as radiation. The NCA states “PDT can cause burns, swelling, pain, and scarring in nearby healthy tissue (3). Other side effects of PDT are related to the area that is treated. They can include coughing, trouble swallowing, stomach pain, painful breathing, or shortness of breath; these side effects are usually temporary.”
According to the American Cancer Society, PDT cannot be utilized to treat metastatic lesions, those which have spread from the initial cancer to other areas of the body. This is because, while the photosensitizing drug does spread throughout the entire body, only the area treated with the light waves are activated.
Individuals will remain sensitive to light in general for approximately six weeks following treatment. It is mainly limited to treating cancers of the skin or just below the skin and within bodily cavities.
One area specifically treated using PDT is the cervix. The FDA is currently set to determine approval of a new device called LuViva later this month which would utilize a form of PDT for diagnostic purposes including precancerous and cancerous cervical lesions.
This would eliminate the need for painful procedures such as cone biopsies and LEEP and the results are available immediately.
Hopefully PDT, whether for diagnostic or treatment purposes, will become more widely used and can eliminate the cancer without the current side effects and complications of conventional use.
The decision by the FDA later this month will hopefully be to approve LuViva. It is also hoped that this technology will become more widely acknowledged and utilized by the medical community in the future.
Sources:
" Photodynamic Therapy for Cancer - National Cancer Institute." Comprehensive Cancer Information - National Cancer Institute. N.p., n.d. Web. 4 Jan. 2012. http://www.cancer.gov/cancertopics/factsheet/Therapy/photodynamic
“Photodynamic Therapy." American Cancer Society:: Information and Resources for Cancer: Breast, Colon, Prostate, Lung and Other Forms. N.p., n.d. Web. 4 Jan. 2012. http://www.cancer.org/Treatment/TreatmentsandSideEffects/TreatmentTypes/photodynamic-therapy
Spencer, Mark. "Guided Therapeutics LuViva Advanced Central Scan Designated an Investment Success Story by National Cancer Institute (GTHP) : OTCBB Stock Analysis." Small Cap Stocks and Penny Stocks for Big Returns - Small Cap Network. N.p., n.d. Web. 4 Jan. 2012.
http://www.smallcapnetwork.com/Guided-Therapeutics-LuViva-Advanced-Central-Scan-Designated-an-Investment-Success-Story-by-National-Cancer-Institute-GTHP/s/via/7474/article/view/p/mid/1/id/39
Reviewed January 4, 2012
by Michele Blacksberg RN
Edited by Jody Smith