The tumor is an organ
The biological basis of the Prostate Photodynamic Therapy finds its roots in a new definition of what is a tumour. Indeed, Prs A. Scherz and Y. Solomon founded their research on a new concept where the tumour is not an anarchic development of abnormal cells but rather a very clever and organized structure with the ability to organize its own environment in order to grow and then metastasize. Amongst the most importance infrastructure needed by the tumour new vessels socalled neovascularization set up in order to supply the cancerous cells with every components to grow and divide. These « vascular motorways » are vital to the survival of the tumoral lesions and their occlusion will undoubtedly lead to the death of all cancer cells (picture 60).
Picture 60 : from the laser activation of Tookad® to the cells death
Occlusion of the targeted vessels
The prostate photodynamic therapy is a vaso-occlusive mechanism were a photosensitizer (Tookad®) injected intravenously is activated by a laser light in order to cause the occlusion of the vessels in the targeted lesion. Unlike most of the photosensitizer, Tookad stays exclusively in the vascular domain and is naturally excreted within 6 hours instead of days or weeks.
The mechanism of action of Tookad® once activated is to create oxide radical into the blood triggering a reaction of the wall of the vessels with first a vasoconstriction and then a complete occlusion. In few hours this brutal starvation brings the cancer to a certain death. Unlike other focal therapies, this process of ablation is non-thermal with a maximal local temperature increase of 4°C staying in the physiological range.
An active ongoing research
The very deep and complicated science behind Prostate Photodynamic Therapy is still intensively studied particularly in a strong collaboration between the Weizman Institute of Science and the Memorial Sloan Kettering Cancer Center under the supervision of Prs A. Scherz and J. Coleman (picture 61). Indeed in addition to the use of Prostate Photodynamic Therapy in multimodal strategies with new molecular targeted therapies, Tookad® is also evaluated in different localisation of cancers such as oesophagus, pancreatic and upper urinary tract. The following slideshow gives you a more detailed presentation of the science behind Prostate Photodynamic Therapy by Tookad® (video 9).
Picture 61 : Compilation of titles of Prostate Photodynamic Therapy-related scientific articles
Video 9 : The deep science behind the Prostate Photodynamic Therapy