Prostate Stereotactic Radiation and Radio-induced Lymphocyte Apoptosis for Predicting Late Toxicities in Prostate Cancer (PROSTERA)

Inclusion Criteria: * Male, aged 60 years or older, presenting with localized prostate cancer of low or intermediate risk (T1-T2 stage, Gleason score 6-7, and PSA \<15 ng/mL) without metastatic disease, and for whom radiotherapy is indicated. * Patient affiliated with, or beneficiary of, the French national health insurance system. * French-speaking patient. * Patient who has been informed about the study and has provided written informed consent. Exclusion Criteria: * Patient unable to read, write, or understand French. * Vulnerable patient as defined in Article L1121-6 of the French Public Health Code. * Adult under legal guardianship, curatorship, or judicial protection. * Patient unable to personally provide informed consent as per Article L1121-8 of the French Public Health Code, or adult protected by law. * Patient already enrolled in an interventional study that could influence the outcomes of the present study. * Patient with a history of prostate and/or digestive surgery. * Refusal to sign the written informed consent at inclusion.