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Vascular Targeted Photodynamic Therapy
Vascular Targeted Photodynamic Therapy (VTPT) is a treatment that can be used for many diseases. Currently this therapy is used to treat certain types of lung cancer, esophageal cancer and pre-cancerous conditions found in the esophagus known as Barrett's syndrome. It can also be effective in removing cancer and pre-cancerous lesions found on the skin. In addition, this therapy is currently being studied in trials for use in treating cervical cancer, prostate cancer and some types of brain cancer.
VTPT represents the newest generation of photodynamic therapy and a new paradigm for minimally invasive ablative therapy.
What is vascular targeted photodynamic therapy?
For the first step in this procedure, the cancerous cells must be made light sensitive via a photosensitizing agent. It uses a drug, called a photosensitiser. This drug is administered through a vein in the arm and is attracted to prostate cancer cells, but is not activated until it is exposed to light energy, usually from laser.
Second step, is to allow an incubation period for the medication to take effect, which can range from a few minutes to a few hours.
The final step is to deliver light to the prostate from a laser, along thin optical fibres. These optical fibres are put into the prostate within clear hollow plastic needles. The needles are put in under general anaesthetic. Then, the activated drug can kill the cells around the light fibre, by producing reactive oxygen species. These are powerful forms of oxygen which can either kill cells directly, or attack the blood vessels which supply the prostate cancer cells.
Most used photosensitiser drug in prostate cancer treatment is WST-09 (Tookad). Photodynamic therapy using this photosensitiser acts on the blood vessels to create its PDT effect, hence it is called Vascular Targeted Photodynamic therapy (VTPT).
How long does VTPT take?
Vascular targeted photodynamic therapy takes about 2-3 hours. This is the time taken for the needles to be put into the prostate, all the ultrasound and light measurements made, and the drug and light dose to be given.
How effective is VTPT for prostate cancer?
Vascular Targeted Photodynamic therapy, like all of the other treatments for prostate cancer, can kill cancer cells as well as normal cells. However, it seems that cancer cells are more sensitive to PDT and normal cells can recover or be repaired much better than cancer cells. It is thought that vascular targeted photodynamic therapy with Tookad may affect the blood vessels which supply tumour cells more than those which supply healthy cells. This is one of the aspects of the treatment that is being investigated in current studies.
Vascular targeteted photodynamic therapy with Tookad has been tried in patients whose prostate cancer came back after radiotherapy. Researchers noticed a reduction in PSA and MRI scans provided evidence of killing prostate cancer cells (cancer and normal cells). It is not yet known whether VTPT could be as effective as other treatments for prostate cancer, but there are big hopes.
Are there any side effects?
Vascular targeteted photodynamic therapy can have fewer of side effects. These can be considered in two groups:
- Those that are related to the procedure :
This includes effects on the urine stream, blood in the urine and frequency of passing urine, which are usually temporary. Effects on sexual function are also possible.
- Those that are related to the photosensitiser drug:
Side effects seen with WST-09 include a temporary change in liver function; a drop in blood pressure in some patients; sensitivity to sunlight and room light, for a few hours at the most.
Studies are being carried out with patients with prostate cancer at present.
Latest news
VTPT: A January 2009 expert overview
Recently, respected experts from prostate cancer field published an important review of the current
evidence surrounding the application of a number of the new and/or evolving treatments available such
as newer technique known as vascular-targeted photodynamic therapy (VTPT).
[ read full article ]
NOTE: Issues on this site regarding prostate cancer and treatment options, are provided for
information only, and are not meant to substitute for the advice of your own physician or other medical professional.
Prostate-Report.org does not endorse any specific product, service or treatment.
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