Photodynamic Therapy (PDT) is an effective treatment for certain cancers.
PDT provides a targeted method of treating tumours by combining the use of a photo-sensitive drug (a photosensitizer) with laser light. As such it is considered to be both minimally invasive and minimally toxic. When the drug is exposed to a specific wavelength of light, a form of oxygen is produced that kills nearby cancer cells.
Unlike other treatments the effect of PDT can be localised. This is achieved in three ways:
- Light is delivered only to tissues that a physician wishes to treat. In the absence of light, there is no activation of the photosensitizer and no cell killing
- Photosensitizers may be administered in ways that restrict their mobility
- Photosensitizers may be chosen which are selectively absorbed at a greater rate by targeted cells.
An increasing number of PDT treatments are being recommended by NICE, the National Institute for Health and Clinical Excellence.
Compared to radiotherapy, chemotherapy and surgical operation for the treatment of cancers, PDT is in almost all cases a much cheaper alternative. Furthermore, post-operative recovery after PDT is typically hours or days rather than weeks.
Each photosensitizer is activated by light of a specific wavelength. This wavelength determines how far the light can travel into the body. Thus, physicians use specific photosensitizers and wavelengths of light to treat different areas of the body with PDT.
In the past the development of PDT has been limited to the treatment of tumours on or under the skin, or on the lining of some internal organs. This has been because most wavelengths of light cannot penetrate through more than 1 cm of tissue using standard laser technology and low powered LED technology. However advances have been made to get round this limitation. These include the use of hollow needles to get the light into deeper tissues, and through the development of new photosensitizers.
The process is sometimes complementary to, or may be an alternative, to chemotherapy, radiotherapy or surgery for certain cancers, with the advantage of not having the side effects associated with these treatments.
The use of PDT can cure some cancers in certain circumstances, and in other cases serve as a palliative. The on-going research into PDT is proving it has many benefits for treating cancer patients and other conditions.
This short animation shows how healthy cells are made in the body - a process that happens millions of times every minute:
Video and Healthy cells copy courtesy of Cancer Research UK
And with prominent link to 'Available Treatments'