@surftohealth88 For IMRT studies have shown for the same biological dose (higher fractions have slightly higher biological effect per Gy) the treatment effectiveness and long-term side effects are about the same. There are higher short-term side effects with higher doses, but no difference is found after 6 months. Trade-off is lower cost and fewer treatments for higher short-term pain. Insurance companies tend to favor fewer treatments since they get the gain while the patient gets the pain.

SBRT targets an ablative dose on the tumor and higher doses are more effective. That is why high risk on ultraProstox (SBRT) does not overlap much with high risk for std Prostox (IMRT). For SBRT to work well the RO needs a well-defined lesion to target. That is not always the case with salvage prostate treatment.