question: Compared to conventional fractionation (39?×?2.0 Gy?=?78.0 Gy given once a day, five days per week)  what was the result of an experimental arm with an extreme hypo-fractionated regimen (7?×?6.1 Gy?=?42.7 Gy given every other weekday, and always including two weekends without RT) on The prostate volumes?
context: The extreme hypo-fractionation regimen used in our study lead to a significant increase in prostate volume after three treatment fractions (EQD23 = 33 Gy). This increase was still apparent at the end of treatment after six fractions (EQD23 = 67 Gy). Our observations indicate that the enlargement of the CTV is both larger than that known for conventional therapy and stays enlarged during the whole treatment course.