title: Toxicity and efficacy of three dose-fractionation regimens of intensity-modulated radiation therapy for localized prostate cancer.
abstract: Outcomes of three protocols of intensity-modulated radiation therapy (IMRT) for localized prostate cancer were evaluated. A total of 259 patients treated with 5-field IMRT between 2005 and 2011 were analyzed. First, 74 patients were treated with a daily fraction of 2.0 Gy to a total of 74 Gy (low risk) or 78 Gy (intermediate or high risk). Then, 101 patients were treated with a 2.1-Gy daily fraction to 73.5 or 77.7 Gy. More recently, 84 patients were treated with a 2.2-Gy fraction to 72.6 or 74.8 Gy. The median patient age was 70 years (range, 54-82) and the follow-up period for living patients was 47 months (range, 18-97). Androgen deprivation therapy was given according to patient risk. The overall and biochemical failure-free survival rates were, respectively, 96 and 82% at 6 years in the 2.0-Gy group, 99 and 96% at 4 years in the 2.1-Gy group, and 99 and 96% at 2 years in the 2.2-Gy group. The biochemical failure-free rate for high-risk patients in all groups was 89% at 4 years. Incidences of Grade ≥ 2 acute genitourinary toxicities were 9.5% in the 2.0-Gy group, 18% in the 2.1-Gy group, and 15% in the 2.2-Gy group (P = 0.29). Cumulative incidences of Grade ≥ 2 late gastrointestinal toxicity were 13% in the 2.0-Gy group at 6 years, 12% in the 2.1-Gy group at 4 years, and 3.7% in the 2.2-Gy group at 2 years (P = 0.23). So far, this stepwise shortening of treatment periods seems to be successful.
authors.affiliation: Department of Radiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho-ku, Nagoya 467-8601, Japan.
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Manabe
authors.forename: Yuta
authors.initials: Y
authors.lastname: Shibamoto
authors.forename: Chikao
authors.initials: C
authors.lastname: Sugie
authors.forename: Fumiya
authors.initials: F
authors.lastname: Baba
authors.forename: Shiho
authors.initials: S
authors.lastname: Ayakawa
authors.forename: Aiko
authors.initials: A
authors.lastname: Nagai
authors.forename: Shinya
authors.initials: S
authors.lastname: Takemoto
authors.forename: Akihiro
authors.initials: A
authors.lastname: Hayashi
authors.forename: Noriyasu
authors.initials: N
authors.lastname: Kawai
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Takeuchi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Ishikura
authors.forename: Kenjiro
authors.initials: K
authors.lastname: Kohri
authors.forename: Takeshi
authors.initials: T
authors.lastname: Yanagi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015897:Comorbidity; D019583:Dose Fractionation, Radiation; D005767:Gastrointestinal Diseases / Q000401:mortality*; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D052801:Male Urogenital Diseases / Q000401:mortality*; D008875:Middle Aged; D011471:Prostatic Neoplasms / Q000401:mortality* / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000401:mortality*; D050397:Radiotherapy, Intensity-Modulated / Q000401:mortality*; D012307:Risk Factors; D015996:Survival Rate; D016896:Treatment Outcome
keywords: hypofractionated radiation therapy; intensity-modulated radiation therapy; prostate cancer