Abstract Book

ESTRO 37

S431

2 Fondazione IRCCS Istituto Nazionale dei Tumori- Milano, Radiotherapy, Milan, Italy 3 Istituto Nazionale dei Tumori “Regina Elena”, Radiotherapy, Rome, Italy 4 Istituto di Candiolo- Fondazione del Piemonte per l'Oncologia IRCCS, Medical Physics, Candiolo Torino, Italy 5 Fondazione IRCCS Istituto Nazionale dei Tumori- Milano, Medical Physics, Milan, Italy 6 Istituto Nazionale dei Tumori “Regina Elena”, Medical Physics, Rome, Italy 7 Ospedale Regionale U.Parini-AUSL Valle d’Aosta, Radiotherapy, Aosta, Italy 8 Ospedale Regionale U.Parini-AUSL Valle d’Aosta, Medical Physics, Aosta, Italy 9 Ospedale di Ivrea- A.S.L. TO4, Radiotherapy, Ivrea, Italy 10 Ospedale di Ivrea- A.S.L. TO4, Medical Physics, Ivrea, Italy 11 Cliniche Gavazzeni-Humanitas, Radiotherapy, Bergamo, Italy 12 Comprensorio Sanitario di Bolzano, Radiotherapy, Bolzano, Italy 13 Ospedale degli Infermi, Radiotherapy, Biella, Italy 14 IRCCS San Raffaele Scientific Institute, Medical Physics, Milan, Italy 15 Programma Prostata- Fondazione IRCCS Istituto Nazionale dei Tumori, Radiotherapy, Milan, Italy 16 IRCCS San Raffaele-, Radiotherapy, Milan, Italy 17 Centro Aktis, Medical Physics, Marano Napoli, Italy 18 Ospedale San Raffaele IRCCS, Medical Physics, Milan, Italy 19 Programma Prostata- Fondazione IRCCS Istituto Nazionale dei Tumori, Medical Physics, Milan, Italy 20 IRCCS San Raffaele Scientific Institute, Radiotherapy, Milan, Italy Purpose or Objective The fear of treatment-induced severe urinary incontinence (SUI) is the main factor affecting patient preference with respect to the treatment of prostate cancer (Avila, IJROBP 2015), and one of the possible sequelae mainly influencing physicians against postoperative RT. Purpose of this study was to investigate the clinico-dosimetric variables affecting the risk of SUI after adjuvant (ADV) or salvage (SALV) RT, and to analyse any possible difference in terms of risk of SUI in pts treated with the two different RT intents. Material and Methods Pts enrolled from in an ongoing multicentric observational trial, registered at ClinicalTrials.gov and aimed at the evaluation of toxicity from RT including prophylactic WPRT were evaluated. Static-field IMRT (11%), Tomotherapy (44%) and VMAT (45%) were allowed. UI was evaluated by means of the ICIQ-SF questionnaire filled in by pts at different time intervals. Median time from prostatectomy to RT (TTRT) and EQD2 RT dose to prostatic bed (PB) for α/β=1Gy were 3.72 vs 24.43 months (p<.0001), and 73.48 vs 74 Gy in ADV and SALV cohort, respectively. Median EQD2 RT dose to pelvic lymph-nodal area (PLNA) was 48.13 Gy in both groups. SUI, corresponding to an ICIQ-SF score ≥13 points (http://www.iciq.net/index.html), was set as endpoint for statistical analyses. The possible role, with respect to the risk of SUI at 12 and 24 months, of a large set of clinical (age, BMI, comorbidities, smoking, antiandrogen deprivation therapy, ADT, and RT intent) and dosimetric (RT technique, EQD2 to PB and PLNA, volume of PLNA, TTRT) variables was analyzed by means of univariate logistic analysis (UA). Variables with a p-value <0.20 at UA were entered into a multivariable analysis (MVA). Results 183 pts (87 ADV/86 SALV) with complete data at baseline and at 1 year were analysed. For 101 of these, data at 2 years were also available. A significant difference in terms of mean ICIQ-SF scores was observed between

has a well-established role in the monitoring of intestinal inflammation in patients (pts) with inflammatory bowel diseases, such as ulcerative colitis and Crohn’s disease. In this preliminary study, urinary calprotectine (UrCALPRO) was used as a potential marker of radiation-induced UT and worsening of urinary function. Material and Methods Forty pts were treated with RT with either radical, adjuvant or salvage intent. An International Prostate Symptoms Score (IPSS) questionnaire was filled-in by pts at baseline, at RT mid-point, end, and 90 days after RT end. With the same schedule, a urine sample was collected and diluted 1:10 in the Diluent Buffer, mixed by vortex (10 sec), and incubated at room temperature for 20 minutes. Levels of UrCALPRO were measured by means of fast immunochromatography assay (Calfast Reader) and the results expressed as mg/kg. The agreement between Calfast and subsequent ELISA assays was good. Results No significant correlation emerged between the baseline levels of UrCALPRO and age, BMI, diabetes, hypertension or RT intent. An increase in UrCALPRO levels with respect to baseline (Fig. 1) was recorded at RT mid-point, end, and 3 months after RT conclusion. A similar trend was observed (Fig. 1) for the overall IPSS score. At Wilcoxon paired samples test, the association between the variations of UrCALPRO levels and IPSS scores (both the 8 single items and the overall sum score) with respect to baseline was always significant at RT end (p≤0.001) and at 3 months (p≤0.02), but not at RT mid-point (p≥0.23). When comparing the variations (delta, D) of total IPSS score (DIPSSTOT, lower part of Fig. 1) with respect to baseline at RT mid-point, end and 3 months after RT end by the median D (≤median, Code 0 vs >median, Code 1) of UrCALPRO with respect to baseline at corresponding time intervals, significant differences in terms of median DIPSS emerged at all the three time intervals (Fig. 1).

Conclusion Although preliminary, these findings suggest UrCALPRO as a potentially robust and easy to use tool for the timely assessment of RT-induced worsening of urinary function. If confirmed on a larger population, its role could be of potentially enormous importance in the timely detection and management of late events, often consequent to severe acute UT. PO-0826 Factors affecting self-reported, long-term (1- 2 yrs) urinary incontinence from post-prostatectomy RT P. Gabriele 1 , B. Avuzzi 2 , G. Sanguineti 3 , A. Maggio 4 , T. Giandini 5 , V. Landoni 6 , F. Munoz 7 , F. Migliaccio 8 , D. Cante 9 , E. Petrucci 10 , V. Vavassori 11 , E. Villa 11 , J. Waskiewicz 12 , P. Farina 12 , B. Farina 13 , G. Girelli 13 , I. Improta 14 , F. Badenchini 15 , B. Noris Chiorda 16 , V. Carillo 17 , C. Sini 18 , R. Valdagni 15 , C. Fiorino 14 , T. Rancati 19 , C. Cozzarini 20 1 Istituto di Candiolo- Fondazione del Piemonte per l'Oncologia IRCCS, Radiotherapy, Candiolo Torino, Italy