Stereotactic Body Radiotherapy

SABR has demonstrated low toxicity and high local control in early-stage NSCLC contexts. The SBRT arm prescribes 36.25 Gy in 5 fractions over 1-2 weeks on a linear accelerator. Ultra-hypofractionated EBRT, also called SBRT, delivers more than 5 Gy per fraction and can complete treatment in as few as five sessions. The protocol defines SABR exposure as radiation doses of at least 5 Gy delivered in 10 or fewer fractions. The PACE-B trial showed level I evidence that five-fraction SBRT was non-inferior to moderately hypofractionated 20-fraction radiotherapy with comparable toxicity. The rationale for SBRT in prostate cancer is that prostate cancer has a low alpha/beta ratio compared with surrounding healthy tissue. SABR is a precise, non-invasive radiation treatment designed to deliver high-dose radiation to tumors while limiting exposure to healthy tissue. For low-risk patients, the SBRT clinical target volume is the prostate only. For intermediate-risk patients, the SBRT clinical target volume includes the prostate and proximal 1 cm of seminal vesicles. SABR-treated patients may be at risk of undetected nodal disease when diagnostic tools produce false-negative results. SABR is acc…