Vascular Targeted-Phototherapy (VTP) or Prostate Photodynamic Therapy or Tookad® Prostate Therapy refers to the same technique based on the use of a photosensitizer (Tookad®) and a laser light. This innovative tissue preserving treatment is a non-thermal oncological focal therapy which aims to destroy the cancerous lesions inside the prostate with an optimal accuracy (picture 57). The genius behind the technique comes from the rationale that the tumour is an organ and creates the necessary environment to develop itself and particularly a neo-vascular system. Targeting the vessels leads the tumour and its surrounding to starve and to die. Prostate Photodynamic Therapy is a vaso-occlusive technique triggered by the combination of a photosensitizer produced from a deep-water seaweed and a laser infra-red light of 753 wave-length. Every centimetre of fiber introduces into the prostate will destroy accurately 1 cm3 of prostatic tissue. Behind a very reproducible and well-mastered technique a huge amount of scientific fundamental, translational and clinical studies are sustaining the rationale of this innovative treatment.
Picture 57 : MRI at day-7 of an hemi-ablation of the right lobe
Prostate Photodynamic Therapy is a vaso-occlusive treatment which aims to create a targeted thrombosis in and around the cancerous lesion. Once injected intravenously the photosensitizer is activated by the laser light to create oxygens radicals. Those radicals generate a reaction of the vessel which is a vasoconstriction then a rapid vascular occlusion and finally the death of the cells fed by the vessels (video 8). Every illuminated part of the prostate is destroyed.
Video 8 : An efficient devascularization of a tumour after activation of Tookad® by the laser light
Published in 2015, the Prostate Photodynamic Therapy technique is well-standardized . It is performed under general anesthesia in high lithotomy position in 3 consecutive steps : 1) ultrasound scan-guided introduction of the needles, 2) injection of the photosensitizer (Tookad®) and 3) illumination of the targeted zone by laser light (picture 58). From the start of the injection until the following day of the procedure, the patient has to be protected by the light.
Picture 58 : Sagittal view of the installation during the illumination phase
During the 12 years of scientific studies the Prostate Photodynamic Therapy technique different indications have evaluated with always the same results. Whether ISUP 1 or 2, any localisation in the prostate roughly the negativation of the biopsies after treatment is around 80-85%. This constant results through all the phase II and III studies on different populations and in dozens of centers through the world (EU, US, Latin America and Middle East) are in favour of the accuracy and the reproducibility of the technique (picture 59). After all those years of scientific evaluation and improvements, rewarded in 2019 at the Harvard Medical School by the International Phototherapy Association , the Prostate Photodynamic Therapy has reached its level of maturity by obtaining in 2017 the approval by the very demanding European Medicine Agency [EMA].
Picture 59 : Lancet Oncology publication February 2017 – Level 1 scientific evidence