title: A prospective comparison of acute intestinal toxicity following whole pelvic versus small field intensity-modulated radiotherapy for prostate cancer.
abstract: OBJECTIVE
  To compare the acute intestinal toxicity of whole pelvic (WP) and small field (SF) intensity-modulated radiotherapy (IMRT) for prostate cancer using dosimetric and metabolic parameters as well as clinical findings.
  
  
  METHODS
  Patients who received IMRT in either a definitive or postoperative setting were prospectively enrolled. Target volume and organs at risk including intestinal cavity (IC) were delineated in every patient by a single physician. The IC volume that received a 10-50 Gy dose at 5-Gy intervals (V10-V50) and the percentage of irradiated volume as a fraction of total IC volume were calculated. Plasma citrulline levels, as an objective biological marker, were checked at three time points: baseline and after exposure to 30 Gy and 60 Gy.
  
  
  RESULTS
  Of the 41 patients, only six experienced grade 1 acute intestinal toxicity. Although all dose-volume parameters were significantly worse following WP than SF IMRT, there was no statistically significant relationship between these dosimetric parameters and clinical symptoms. Plasma citrulline levels did not show a serial decrease by radiotherapy volume difference (WP versus SF) and were not relevant to the irradiated doses.
  
  
  CONCLUSIONS
  Given that WP had comparable acute intestinal toxicities to those associated with SF, WP IMRT appears to be a feasible approach for the treatment of prostate cancer despite dosimetric disadvantages.
authors.affiliation: Department of Radiation Oncology, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Republic of Korea.
authors.forename: Yeon Joo
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Department of Radiation Oncology, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Republic of Korea.
authors.forename: Jin-Hong
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Radiation Oncology, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Republic of Korea.
authors.forename: In-Ha
authors.initials: IH
authors.lastname: Yun
authors.affiliation: Department of Radiation Oncology, Asan Medical Center, College of Medicine, University of Ulsan, Seoul, Republic of Korea.
authors.forename: Young Seok
authors.initials: YS
authors.lastname: Kim
keywords: citrulline; intensity-modulated radiotherapy; intestinal toxicity; prostate cancer