Proton beam therapy can provide a therapeutic gain by offering at least equivalent (or superior) tumor control while reducing the risk of radiation toxicity, in comparison with conventional photon-based external beam radiotherapy, given its dose-deposition characteristics. Currently the clinical target volume of proton beam for the treatment of prostate cancer has been mostly limited to the prostate and the seminal vesicles. There has been no study of proton beam therapy to treat both the primary tumor in the prostate and the regional pelvic nodes simultaneously using a moderate hypofractionation regimen.
The study is a prospective, single-arm, clinical trial to evaluate a moderate hypofractionation regimen of proton beam therapy for high risk or unfavorable intermediate risk prostate cancer. The clinical target volumes of proton beam therapy include both the prostate/seminal vesicles and the regional pelvic nodes. The primary objective is to assess late grade ≥ 3 gastrointestinal (GI) and genitourinary (GU) toxicity. The secondary objectives are to evaluate late grade ≥ 2 GI and GU toxicity, acute grade ≥ 3 GI and GU toxicity, and disease-free survival including freedom from PSA (prostate specific antigen) relapse at 5 years. The study provides an avenue to examine the safety, efficacy, cost effectiveness, and convenience of a moderate hypofractionation regimen (5-week course) of proton beam therapy.
