An investigation of metronomic photodynamic therapies for local prostate cancer: supplementary fluorescent photography and proteomic studies, as measurable parameters of this treatment.

Abstract

Aim: To investigate the clinical effects of metronomic Photodynamic therapy in prostate cancer patients, using different chlorophyll based photosensitisers. Methods and materials: The patients who enrolled in this ethics approved Phase 1 prostate cancer trial were treated with a variable combination of targeted photo-dynamic therapies and coupled ultrasound energies, mediated through orally/sub-lingually administered chlorophyll based photosensitisers. The metronomic technique involves the repeated administration of both the photosensitiser(s) and energies over set time intervals. As scientific assessment of the prostate cancer effects, intra-treatment fluorescent photography of the prostate gland /prostatic fossa, together with proteomic based urine specimen studies were performed. Results: The clinical data involved 666 treatment episodes, 333 photosensitiser dosages and includes 3-5 years patient follow-up. The effects on the prostate symptoms and cancer are documented, prostate size reduction being a serendipitous finding. Real time fluorescent photography has documented qualitative reproducible data. The quantitative urinary proteomic studies demonstrated statistically significant results, as documentation of the known pathological effects, attributable to this treatment. Conclusion: This study has been shown to be safe and to meet the criteria required of a TGA Phase 1 trial and reports the clinical and investigational prostate cancer responses to the metronomic therapy, involving the three different photosensitisers. The scientific bases for this therapy have been validated with the real-time fluorescent photographic and proteomic analyses data, of particular interest and importance are the immune system results. The new word metapoptosis is suggested as the description for PDT induced malignant cell death in association with immune stimulation, as described in this study.