title: Development of a set of nomograms to predict acute lower gastrointestinal toxicity for prostate cancer 3D-CRT.
abstract: OBJECTIVE
  To predict acute Radiation Therapy Oncology Group (RTOG)/European Organization for Research and Treatment of Cancer (EORTC) and Subjective Objective Signs Management and Analysis/Late Effect of Normal Tissue (SOMA/LENT) toxicities of the lower gastrointestinal (LGI) syndrome in patients with prostate cancer undergoing three-dimensional conformal radiotherapy using a tool (nomogram) that takes into account clinical and dosimetric variables that proved to be significant in the Italian Association for Radiation Oncology (AIRO) Group on Prostate Cancer (AIROPROS) 0102 trial.
  
  
  METHODS
  Acute rectal toxicity was scored in 1,132 patients by using both the RTOG/EORTC scoring system and a 10-item self-assessed questionnaire. Correlation between clinical variables/dose-volume histogram constraints and rectal toxicity was investigated by means of multivariate logistic analyses. Multivariate logistic analyses results were used to create nomograms predicting the symptoms of acute LGI syndrome.
  
  
  RESULTS
  Mean rectal dose was a strong predictor of Grade 2-3 RTOG/EORTC acute LGI toxicity (p = 0.0004; odds ratio (OR) = 1.035), together with hemorrhoids (p = 0.02; OR = 1.51), use of anticoagulants/antiaggregants (p = 0.02; OR = 0.63), and androgen deprivation (AD) (p = 0.04; OR = 0.65). Diabetes (p = 0.34; OR = 1.28) and pelvic node irradiation (p = 0.11; OR = 1.56) were significant variables to adjust toxicity prediction. Bleeding was related to hemorrhoids (p = 0.02; OR = 173), AD (p = 0.17; OR = 0.67), and mean rectal dose (p = 0.009; OR = 1.024). Stool frequency was related to seminal vesicle irradiation (p = 0.07; OR = 6.46), AD administered for more than 3 months (p = 0.002; OR = 0.32), and the percent volume of rectum receiving more than 60 Gy (V60Gy) V60 (p = 0.02; OR = 1.02). Severe fecal incontinence depended on seminal vesicle irradiation (p = 0.14; OR = 4.5) and V70 (p = 0.033; OR = 1.029).
  
  
  CONCLUSIONS
  To the best of our knowledge, this work presents the first set of nomograms available in the literature specific to symptoms of LGI syndrome and provides clinicians with a tailored probability of the specific outcome. Validation of the tool is in progress.
authors.affiliation: Prostate Programme, Fondazione IRCCS, Istituto Nazionale dei Tumori, Milano, Italy.
authors.forename: Riccardo
authors.initials: R
authors.lastname: Valdagni
authors.forename: Tiziana
authors.initials: T
authors.lastname: Rancati
authors.forename: Claudio
authors.initials: C
authors.lastname: Fiorino
authors.forename: Gianni
authors.initials: G
authors.lastname: Fellin
authors.forename: Alessandro
authors.initials: A
authors.lastname: Magli
authors.forename: Michela
authors.initials: M
authors.lastname: Baccolini
authors.forename: Carla
authors.initials: C
authors.lastname: Bianchi
authors.forename: Emanuela
authors.initials: E
authors.lastname: Cagna
authors.forename: Carlo
authors.initials: C
authors.lastname: Greco
authors.forename: Flora A
authors.initials: FA
authors.lastname: Mauro
authors.forename: Angelo F
authors.initials: AF
authors.lastname: Monti
authors.forename: Fernando
authors.initials: F
authors.lastname: Munoz
authors.forename: Michele
authors.initials: M
authors.lastname: Stasi
authors.forename: Paola
authors.initials: P
authors.lastname: Franzone
authors.forename: Vittorio
authors.initials: V
authors.lastname: Vavassori
mesh_terms: D000465:Algorithms; D015897:Comorbidity; D004307:Dose-Response Relationship, Radiation; D005767:Gastrointestinal Diseases / Q000453:epidemiology*; D006801:Humans; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D008297:Male; D008954:Models, Biological; D017063:Outcome Assessment, Health Care / Q000379:methods*; D011379:Prognosis; D011471:Prostatic Neoplasms / Q000453:epidemiology* / Q000532:radiotherapy*; D011832:Radiation Injuries / Q000453:epidemiology*; D011879:Radiotherapy Dosage; D020266:Radiotherapy, Conformal / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D012680:Sensitivity and Specificity; D016896:Treatment Outcome