title: Monotherapeutic high-dose-rate brachytherapy for prostate cancer: a dose reduction trial.
abstract: OBJECTIVE
  To report preliminary results of our second regimen with 45.5 Gy/7 fractions aiming to reduce toxicity, compared with our first regimen with 54 Gy/9 fractions, using high-dose-rate (HDR) brachytherapy as monotherapy for prostate cancer.
  
  
  METHODS
  From 2005 through 2010, 63 patients with localized prostate cancer were treated with HDR brachytherapy alone in 45.5 Gy/7 fractions for 4 days. Thirty-four patients were considered as intermediate-risk and 29 as high-risk. Thirty-seven patients also received neoadjuvant and/or adjuvant hormonal therapy. Biologically effective dose assuming α/β=1.5 Gy (BED₁.₅) was reduced from 270 Gy to 243 Gy, and BED₃.₀ from 162 Gy to 144 Gy, compared to previous 54 Gy/9 fractions for 5 days.
  
  
  RESULTS
  Median follow-up time was 42 months (range 13-72). Grade 2 acute toxicities occurred in six (9.5%), late toxicities in five (7.9%) patients, and Grade 3 or higher in none. Grade 2 late gastrointestinal toxicity rate was 1.6%, compared with 7.1% for the 54 Gy regimen. Three-year PSA failure-free rates for intermediate- and high-risk patients were 96% and 90%, which were comparable to 93% and 85% for the 54 Gy regimen.
  
  
  CONCLUSIONS
  Compared to the 54 Gy/9 fractions regimen, dose-reduced regimen of 45.5 Gy/7 fractions using HDR brachytherapy as monotherapy preliminarily showed an equivalent or lower incidence rate for acute and late toxicities without compromising the excellent PSA failure-free rate. Further studies with more patients and longer follow-up are warranted.
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Japan. Electronic address: yoshioka@radonc.med.osaka-u.ac.jp.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yoshioka
authors.affiliation: Department of Radiation Oncology, Osaka Medical Center for Cancer and Cardiovascular Diseases, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Konishi
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Suzuki
authors.affiliation: Department of Urology, Osaka University Graduate School of Medicine, Japan.
authors.forename: Yasutomo
authors.initials: Y
authors.lastname: Nakai
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Japan.
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Isohashi
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Seo
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Otani
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Koizumi
authors.affiliation: Department of Radiology, Osaka Medical College, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Yoshida
authors.affiliation: Department of Radiology, Kyoto Prefectural University of Medicine, Japan.
authors.forename: Hideya
authors.initials: H
authors.lastname: Yamazaki
authors.affiliation: Department of Urology, Osaka University Graduate School of Medicine, Japan.
authors.forename: Norio
authors.initials: N
authors.lastname: Nonomura
authors.affiliation: Department of Radiation Oncology, Osaka University Graduate School of Medicine, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Ogawa
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000379:methods*; D004307:Dose-Response Relationship, Radiation; D006801:Humans; D007610:Kallikreins / Q000097:blood; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology / Q000532:radiotherapy*
chemical_list: C549870:KLK3 protein, human; D007610:Kallikreins; D017430:Prostate-Specific Antigen
keywords: High-dose-rate (HDR) brachytherapy; Hypofractionation; Monotherapy; Prostate cancer; Radiotherapy