Development of a set of nomograms to predict acute lower gastrointestinal toxicity for prostate cancer 3D-CRT.
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.
Valdagni
Riccardo
R
Prostate Programme, Fondazione IRCCS, Istituto Nazionale dei Tumori, Milano, Italy.
Rancati
Tiziana
T
Fiorino
Claudio
C
Fellin
Gianni
G
Magli
Alessandro
A
Baccolini
Michela
M
Bianchi
Carla
C
Cagna
Emanuela
E
Greco
Carlo
C
Mauro
Flora A
FA
Monti
Angelo F
AF
Munoz
Fernando
F
Stasi
Michele
M
Franzone
Paola
P
Vavassori
Vittorio
V
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