The study is to examine a moderate hypofractionation regimen of proton beam therapy for high
risk or unfavorable intermediate risk prostate cancer. The prostate and seminal vesicles are
treated with 6750 centigray (RBE) in 25 fractions (i.e. 270 centigray/fraction), while the
regional pelvic nodes receive 4500 centigray (RBE) in 25 fractions (i.e. 180
centigray/fraction) simultaneously. The overall treatment time is 5 weeks.