Post-marketing Surveillance Regarding Efficacy and Safety of SpaceOAR™

Inclusion Criteria: * Patient is suffering from pathologically confirmed T1-T2, N0, M0 prostate adenocarcinoma. * Patient is intended to receive radiation therapy (3D-computerized radiotherapy, intensity-modulated radiotherapy, and/or brachytherapy) and this will be the first prostate or pelvic radiation therapy. * Patient is intended to receive SpaceOAR™ Gel therapy. * The patient is official patient of the clinical investigator in the study centre. * Patient agrees to fully participate in the clinical trial and give informed consent in writing. Exclusion Criteria: * Anatomic abnormality, physical or pathological condition precluding the implantation. * Failure in the wall of the perineum room (with the risk that the hydrogel escapes). * History of prostate surgery or local prostate cancer therapy. * Rectal injury before implantation of SpaceOAR™ Gel or history of or active inflammatory rectal disease such as Crohn's disease or ulcerative colitis. * History of or current perirectal or anal disease or surgery such as prolapsed or bleeding haemorrhoids or fistula. * Compromised immune system (e.g., HIV/acquired immunodeficiency syndrome, auto¬immune disease or immunosuppressive therapy). * Platelet count, partial thromboplastin time, or white blood cell count out of normal laboratory range. * Contraindication for safe MRI and CT scans. * Patient is not able to fully participate in this study including the follow-up (e.g. for mental or geographical reasons, or patient is intravenous drug user or has strong potential for non-compliance to medical regimes). * Patient is mentally unable to understand the nature, aims, or possible consequences of the clinical investigation. * Patient has restricted legal capacity. * Patient did participate in another clinical investigation during the last 3 months. * Patient has revoked the consent.