title: Acute and late gastrointestinal toxicity after radiotherapy in prostate cancer patients: consequential late damage.
abstract: OBJECTIVE
  Late gastrointestinal (GI) toxicity after radiotherapy can be partly explained by late effects of acute toxicity (consequential late damage). We studied whether there is a direct relationship between acute and late GI toxicity.
  
  
  METHODS
  A total of 553 evaluable patients from the Dutch dose escalation trial (68 Gy vs. 78 Gy) were included. We defined three outcomes for acute reactions: 1) maximum Radiation Therapy Oncology Group acute toxicity, 2) maximum acute mucous discharge (AMD), and 3) maximum acute proctitis. Within a multivariable model, late endpoints (overall toxicity and five toxicity indicators) were studied as a function of acute toxicity, pretreatment symptoms, and relevant dose parameters.
  
  
  RESULTS
  At multivariable analysis, AMD and acute proctitis were strong predictors for overall toxicity, "intermittent bleeding," and "incontinence pads" (p < or = 0.01). For "stools > or =6/day" all three were strong predictors. No significant associations were found for "severe bleeding" and "use of steroids." The predictive power of the dose parameters remained at the same level or became weaker for most late endpoints.
  
  
  CONCLUSIONS
  Acute GI toxicity is an independent significant predictor of late GI toxicity. This suggests a significant consequential component in the development of late GI toxicity.
authors.affiliation: Department of Radiation Oncology, The Netherlands Cancer Institute--Antoni van Leeuwenhoek Hospital, Amsterdam, The Netherlands. w.heemsbergen@nki.nl
authors.forename: Wilma D
authors.initials: WD
authors.lastname: Heemsbergen
authors.forename: Stéphanie T H
authors.initials: ST
authors.lastname: Peeters
authors.forename: Peter C M
authors.initials: PC
authors.lastname: Koper
authors.forename: Mischa S
authors.initials: MS
authors.lastname: Hoogeman
authors.forename: Joos V
authors.initials: JV
authors.lastname: Lebesque
mesh_terms: D000208:Acute Disease; D000368:Aged; D017326:Clinical Trials, Phase III as Topic; D005242:Fecal Incontinence / Q000209:etiology; D006471:Gastrointestinal Hemorrhage / Q000209:etiology; D006801:Humans; D008297:Male; D009093:Mucus / Q000378:metabolism; D015999:Multivariate Analysis; D011349:Proctitis / Q000209:etiology; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000150:complications*; D020266:Radiotherapy, Conformal / Q000009:adverse effects; D016032:Randomized Controlled Trials as Topic; D012007:Rectum / Q000528:radiation effects*; D012044:Regression Analysis