ONE-SHOT Trial - Ultra-hypofractionated Single-dose SBRT for Prostate Cancer

The main objective of the phase I/II trial is to determine the safety and efficacy of a single fraction SBRT at a dose of 19 Gy in patients with localized prostate cancer.

Total dose and dose per fraction play an important role in the curative treatment of prostate cancer with radiotherapy (RT). Modern image guided external RT allows safe dose escalation of prostate cancer. There are strong radiobiological and clinical considerations that suggest that treatment with a small number of large fractions (hypofractionation) may increase the therapeutic ratio of RT for prostate cancer by increasing the tumor cell killing effect with relatively less toxic effect on the surrounding late responding normal tissues compared to conventional fractionation. The question of how far can the number of fractions with SBRT be reduced is an exciting research matter with an undoubtful goal, face the challenge of assessing the potential for cure of prostate cancer patients with a single and unique fraction of high dose irradiation similar to what is already undertaken with radiosurgery against brain, lung, and liver targets. We hypothesize that an ultra-hypofractionated single-dose SBRT employing state of the art of image-guided RT techniques may be feasible, with a safe toxicity profile and an optimal long-term tumor control. Hence, a prospective phase I/II clinical trial will be initiated in prostate cancer patients with a localized disease to validate this treatment schedule as an alternative to normofractionated/moderate hypofractionated RT schedules to be tested in a second time in a phase III trial.