Hypofractionated radiosurgery with 5 fractions is considered standard of care for localized prostate cancer. The investigators initiated this multicenter phase II prospective trial to analyse feasibility (toxicity) of hypofractionated radiosurgery with 3 fractions in patients with localised prostate cancer under the hypothesis that the ratio of patients with late GU and GI toxicity ≥ grade 2 after 1 year amounts to 8.4% and 1.3% and is significant lower than 16.4% and 5.7% currently.

Experimental radiosurgery of the prostate with 3 fractions each with 9.5 -10.5 Gy (total application rate of 28.5-31.5 Gy) based on risk grading.

Planned visits are: Baseline, visits at every radiation day and four follow ups (4-6 weeks, 3 months, 6 months and one year after last day of radiation).

Inclusion Criteria:

• Localised, histopathologically confirmed Prostate Cancer (cT1-T2c N0 M0)
• Gleason-grade ≤7, ISUP Grade Group 1-3
• Guideline-based staging
• Age ≥ 18 years
• PSA < 20 ng/ml
• Volume of the prostate < 80 cm³
• IPSS-Score ≤ 12
• Written informed consent

Exclusion Criteria:

• History of prior pelvic radiotherapy
• Previous transurethral resection, laser enucleation or prostate ablation
• Contraindication to MRI or Fiducial marker implantation (e.g. gold allergy)
• Relevant comorbidity thought to adversely affect treatment compliance
• Legal incapacity or lack of informed consent