This study evaluates whether adaptive stereotactic body radiotherapy (SBRT) provides dosimetric advantages compared to non-adaptive SBRT in localized prostate cancer. Five low-dose CT scans are performed before each SBRT session to assess anatomical variations (bladder filling, rectal volume) and determine if a dosimetric recalculation would have been required. The study also evaluates cumulative dose to organs at risk, patient-reported quality of life over 24 months, and overall and recurrence-free survival.