Multi-variable models predicting specific patient-reported acute urinary symptoms after radiotherapy for prostate cancer: Results of a cohort study.
OBJECTIVE
A prospective trial started in 2010, aiming at developing models for urinary toxicity and erectile dysfunction after radiotherapy for prostate cancer. This analysis is finalised at highlighting correlations between clinical/dosimetric factors and acute urinary specific symptoms, as measured by single questions of the International Prostate Symptom Score (IPSS).


METHODS
IPSS was prospectively collected before and at the end of radiotherapy; absolute weekly bladder dose-surface histograms (DSHw) were chosen as dosimetric descriptors. Relevant clinical factors were prospectively gathered. Backward feature selection was used to identify variables to be included in logistic models for moderate-severe (scores⩾4) urinary symptoms.


RESULTS
Complete data of 262 patients (120 conventional fractionation, 142 hypofractionation) were available. Smoking was a strong predictor for feeling of incomplete emptying, frequency, intermittency, urgency and straining; neoadjuvant hormonal therapy and use of antihypertensive drugs were risk factors for intermittency and weak stream, respectively. The baseline score was a major predictor for all symptoms with the exception of intermittency. DSHw were correlated to increased risk of frequency, intermittency, urgency and nocturia. Most models showed moderate-high discrimination (AUC≈0.60-0.79).


CONCLUSIONS
Smoking and other clinical and dosimetric factors predict for specific moderate-severe acute urinary symptoms; baseline condition heavily modulated the risk in most endpoints.
Radiotherapy, San Raffaele Scientific Institute, Milano, Italy.
Cesare
C
Cozzarini
Prostate Cancer Program, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy. Electronic address: tiziana.rancati@istitutotumori.mi.it.
Tiziana
T
Rancati
Medical Physics, San Raffaele Scientific Institute, Milano, Italy.
Viviana
V
Carillo
Prostate Cancer Program, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
Francesco
F
Civardi
Radiotherapy, IRCCS-Candiolo, Italy.
Elisabetta
E
Garibaldi
Radiotherapy, Ospedale Regionale U.Parini-AUSL Valle d'Aosta, Italy.
Pierfrancesco
P
Franco
Radiation Oncology 1,Fondazione IRCCS Istituto Nazionale dei Tumori, Milano, Italy.
Barbara
B
Avuzzi
Radiotherapy, Ospedale Bellaria, Bologna, Italy.
Claudio Degli
CD
Esposti
Radiotherapy, Ospedale ASL9, Ivrea, Italy.
Giuseppe
G
Girelli
Radiation Therapy Unit, Department of Oncology and Advanced Technology, ASMN Hospital IRCCS, Reggio Emilia, Italy.
Cinzia
C
Iotti
Medical Physics, San Raffaele Scientific Institute, Milano, Italy.
Federica
F
Palorini
Radiotherapy, Cliniche Gavazzeni-Humanitas, Bergamo, Italy.
Vittorio
V
Vavassori
Prostate Cancer Program, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Radiation Oncology 1,Fondazione IRCCS Istituto Nazionale dei Tumori, Milano, Italy.
Riccardo
R
Valdagni
Medical Physics, San Raffaele Scientific Institute, Milano, Italy.
Claudio
C
Fiorino
D000368:Aged; D000369:Aged, 80 and over; D001918:Brachytherapy / Q000009:adverse effects / Q000379:methods; D019583:Dose Fractionation, Radiation; D007172:Erectile Dysfunction / Q000209:etiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011471:Prostatic Neoplasms / Q000532:radiotherapy*; D011879:Radiotherapy Dosage; D014555:Urination Disorders / Q000209:etiology*
Acute urinary toxicity; Dose–volume constraints; Modelling; Prostate cancer