Multi-variable models predicting specific patient-reported acute urinary symptoms after radiotherapy for prostate cancer: Results of a cohort study.

PURPOSE - 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).

MATERIALS/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.

Radiother Oncol. 2015 Aug 11. pii: S0167-8140(15)00409-0. doi: 10.1016/j.radonc.2015.07.048. [Epub ahead of print]

Cozzarini C1, Rancati T2, Carillo V3, Civardi F4, Garibaldi E5, Franco P6, Avuzzi B7, Esposti CD8, Girelli G9, Iotti C10, Palorini F3, Vavassori V11, Valdagni R12, Fiorino C3.

1 Radiotherapy, San Raffaele Scientific Institute, Milano, Italy.
2 Prostate Cancer Program, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
3 Medical Physics, San Raffaele Scientific Institute, Milano, Italy.
4 Prostate Cancer Program, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.
5 Radiotherapy, IRCCS-Candiolo, Italy.
6 Radiotherapy, Ospedale Regionale U.Parini-AUSL Valle d'Aosta, Italy.
7 Radiation Oncology 1,Fondazione IRCCS Istituto Nazionale dei Tumori, Milano, Italy.
8 Radiotherapy, Ospedale Bellaria, Bologna, Italy.
9 Radiotherapy, Ospedale ASL9, Ivrea, Italy.
10 Radiation Therapy Unit, Department of Oncology and Advanced Technology, ASMN Hospital IRCCS, Reggio Emilia, Italy.
11 Radiotherapy, Cliniche Gavazzeni-Humanitas, Bergamo, Italy.
12 Prostate Cancer Program, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy; Radiation Oncology 1,Fondazione IRCCS Istituto Nazionale dei Tumori, Milano, Italy.