title: Radiation dose-volume effects in radiation-induced rectal injury.
abstract: The available dose/volume/outcome data for rectal injury were reviewed. The volume of rectum receiving >or=60 Gy is consistently associated with the risk of Grade >or=2 rectal toxicity or rectal bleeding. Parameters for the Lyman-Kutcher-Burman normal tissue complication probability model from four clinical series are remarkably consistent, suggesting that high doses are predominant in determining the risk of toxicity. The best overall estimates (95% confidence interval) of the Lyman-Kutcher-Burman model parameters are n = 0.09 (0.04-0.14); m = 0.13 (0.10-0.17); and TD(50) = 76.9 (73.7-80.1) Gy. Most of the models of late radiation toxicity come from three-dimensional conformal radiotherapy dose-escalation studies of early-stage prostate cancer. It is possible that intensity-modulated radiotherapy or proton beam dose distributions require modification of these models because of the inherent differences in low and intermediate dose distributions.
authors.affiliation: Department of Radiation Oncology, Washington University School of Medicine, St. Louis, MO 63110, USA. jmichalski@radonc.wustl.edu
authors.forename: Jeff M
authors.initials: JM
authors.lastname: Michalski
authors.forename: Hiram
authors.initials: H
authors.lastname: Gay
authors.forename: Andrew
authors.initials: A
authors.lastname: Jackson
authors.forename: Susan L
authors.initials: SL
authors.lastname: Tucker
authors.forename: Joseph O
authors.initials: JO
authors.lastname: Deasy
mesh_terms: D005544:Forecasting; D006471:Gastrointestinal Hemorrhage / Q000209:etiology; D006801:Humans; D008954:Models, Biological; D015233:Models, Statistical; D011832:Radiation Injuries / Q000150:complications*; D011859:Radiography; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000009:adverse effects; D012007:Rectum / Q000000981:diagnostic imaging / Q000528:radiation effects*; D012306:Risk