@jeffmarc wrote "Your numbers are the exact opposite of normal. They would give you five sessions to your prostate…"

Mystery solved! It's about billing (at least originally).

According to Dr Walsh's book, the 1-week/5-session limit for SBRT "is likely related to the length of time required for each treatment session, as well as to an odd Medicare rule that decreases the hospital's reimbursement if more than five treatment sessions are given with this particular machine."

According to the book, moderate hypofractionated SBRT (4–5 weeks) has been the global standard of care since about 2018, but extreme hypofractionated (1 week) is getting more support to show that it's also safe, especially for low/intermediate risk PCa, so it's not *just* about the billing. 🙂