Photodynamic Cancer Therapy - Photodynamic Therapy for Cancer

Photodynamic Cancer Therapy
ITL Cancer Clinic

Photodynamic therapy (PDT) is a special form of phototherapy, a term which includes all treatments which use light to induce reactions in the body which are of benefit to patients.

PDT is a developing technique which can potentially destroy unwanted tissue, whilst sparing normal tissue. First a drug called a photosensitiser is administered to the patient, usually by injection. The photosensitiser alone is harmless and has no effect on either healthy or abnormal tissue. However, when light (often from a laser) is directed onto tissue containing the drug, the drug becomes activated and the tissue is rapidly destroyed, but only precisely where the light has been directed. Thus, by careful application of the light beam, the technique can be targeted selectively to the abnormal tissue.

Some of the drugs being developed also have the desirable property of concentrating in tumours (and certain other kinds of proliferating tissue) relative to the surrounding healthy tissue, which also helps in targeting. There is only one potentially adverse effect - some drugs can result in skin photosensitivity, which means that patients must stay out of bright light for some time following the administration of the drug.

PDT, using the drug Photofrin®, has now been approved as a therapy for, as yet, a limited number of applications in various parts of the world including the UK and it is now clear that there are some indications where PDT is at least as good as and possibly better than alternative treatments. However it has to be emphasised that PDT is still largely an experimental therapy and is currently only applicable to a very small range of patients. More research is needed to further develop and assess PDT with different drugs in different clinical situations. Nevertheless there is growing confidence that PDT will soon become an added weapon in the fight against cancer and other diseases.