title: Stereotactic body radiotherapy for prostate cancer: a preliminary report.
abstract: OBJECTIVE
  We report the results of a retrospective study of stereotactic body radiotherapy (SBRT) using a Cyberknife for prostate cancer.
  
  
  METHODS
  In all 29 patients were treated with hypofractionated SBRT using a Cyberknife at median 36 Gy in five fractions. All the patients were treated with a radical aim. Prostate-specific antigen (PSA) was evaluated at baseline and after radiotherapy. Acute (≤3 months) and late (>3 months) urinary and rectal toxicities were recorded according to the CTCAE version 4.0.
  
  
  RESULTS
  The median duration of follow up was 41 months. PSA values decreased in a time-dependent way. The median PSA nadir was 0.329 ng/mL, achieved after a median of 23 months' follow up. Two patients had a PSA failure according to the definition of nadir + 2 ng/mL. Eight patients (28%) had a benign PSA bounce at median 9 months after radiotherapy. CTCAE Grade 2 and 3 late urinary toxicities were reported in 3 and 3%, respectively. One patient had exacerbated urinary symptoms and received an operation. There were no severe late rectal toxicities.
  
  
  CONCLUSIONS
  The preliminary findings of our study suggest SBRT is feasible for prostate cancer treatment. Further studies with more patients and longer follow-up duration are required.
authors.affiliation: Departments of Radiation Oncology, the Catholic University of Korea, Seoul, Korea.
authors.forename: Yun Hee
authors.initials: YH
authors.lastname: Lee
authors.forename: Seok Hyun
authors.initials: SH
authors.lastname: Son
authors.forename: Sei Chul
authors.initials: SC
authors.lastname: Yoon
authors.forename: Mina
authors.initials: M
authors.lastname: Yu
authors.forename: Byung Ock
authors.initials: BO
authors.lastname: Choi
authors.forename: Yeon Sil
authors.initials: YS
authors.lastname: Kim
authors.forename: Hong Seok
authors.initials: HS
authors.lastname: Jang
authors.forename: Sang Nam
authors.initials: SN
authors.lastname: Lee
authors.forename: Ji Sun
authors.initials: JS
authors.lastname: Jang
authors.forename: Tae Kon
authors.initials: TK
authors.lastname: Hwang
mesh_terms: D000368:Aged; D018572:Disease-Free Survival; D006801:Humans; D007610:Kallikreins / Q000097:blood; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D017430:Prostate-Specific Antigen / Q000097:blood; D011471:Prostatic Neoplasms / Q000097:blood / Q000473:pathology / Q000601:surgery*; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D011879:Radiotherapy Dosage; D011880:Radiotherapy Planning, Computer-Assisted; D012189:Retrospective Studies
chemical_list: C549870:KLK3 protein, human; D007610:Kallikreins; D017430:Prostate-Specific Antigen