Phase II feasibility study of high-dose radiotherapy for prostate cancer using proton boost therapy: first clinical trial of proton beam therapy for prostate cancer in Japan.
OBJECTIVE
To assess the feasibility of high-dose radiotherapy for prostate cancer using proton boost therapy following photon radiotherapy.


METHODS
The primary endpoint was acute grade 3 or greater genitourinary (GU) and gastrointestinal (GI) toxicities. The study included patients with clinical stage T1-3N0M0 prostate cancer. Radiotherapy consisted of 50 Gy/25 fx photon irradiation to the prostate and the bilateral seminal vesicles followed by proton boost of 26 Gy(E)/13 fx to the prostate alone. Hormonal therapy was allowed before and during the radiation therapy.


RESULTS
Between January 2001 and January 2003, 30 patients were enrolled in this study. Acute grade 1/2 GU and GI toxicities were observed in 20/4 and 17/0 patients, respectively. With the median follow-up period of 30 months (range 20-45), late grade 1/2 GU and GI toxicities occurred in 2/3 and 8/3 patients, respectively. No grade 3 or greater acute or late toxicities were observed. All patients were alive, but six patients relapsed biochemically after 7-24 months.


CONCLUSIONS
Proton boost therapy following photon radiotherapy for prostate cancer is feasible. To evaluate the efficacy and safety of proton beam therapy, a multi-institutional phase II trial is in progress in Japan.
Nihei
Keiji
K
Radiation Oncology Division, National Cancer Center Hospital East, Kashiwa, Chiba 277-8577, Japan. knihei@east.ncc.go.jp
Ogino
Takashi
T
Ishikura
Satoshi
S
Kawashima
Mitsuhiko
M
Nishimura
Hideki
H
Arahira
Satoko
S
Onozawa
Masakatsu
M
D000230:Adenocarcinoma / Q000473:pathology / Q000532:radiotherapy*; D000368:Aged; D000369:Aged, 80 and over; D004307:Dose-Response Relationship, Radiation; D005240:Feasibility Studies; D005767:Gastrointestinal Diseases / Q000209:etiology; D006801:Humans; D008297:Male; D052801:Male Urogenital Diseases / Q000209:etiology; D008875:Middle Aged; D009367:Neoplasm Staging; D017785:Photons / Q000627:therapeutic use; D011349:Proctitis / Q000209:etiology; D011471:Prostatic Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects / Q000379:methods*; D016019:Survival Analysis; D016896:Treatment Outcome; D014555:Urination Disorders / Q000209:etiology