ESTRO 37 Abstract book

ESTRO 37

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patients treated with ADV or SALV intent at baseline (7.4 vs 4.6, p<0.0001, t-test) but not at 12 (7.8 vs 7, p=0.26) or at 24 months (9 vs 7.3, p=0.07). The corresponding median values were 7 vs 4, 7 vs 6 and 8 vs 5.5, respectively. 15%, 19% and 25% of pts experienced SUI at baseline and at 1 and 2 years, respectively. At MVA, the 3 variables independently predictive of SUI at 1 year were baseline ICIQ-SF score (OR 1.39), hypertension (OR 1.66) and TTRT (OR 0.97), (AUC 0.865, optimism1%), while baseline ICIQ-SF score (OR 1.35), ADT (OR 1.54 - 2.24 when considering antiandrogens only) and EQD2 to PB (OR 1.15) emerged as the 3 variables independently predictive of SUI at 2 years (AUC 0.864, optimism 3%, Fig. 1).

according to NCCN classification, respectively. Concurrent androgen deprivation therapy (ADT) and anti- coagulation therapy were used in 70.1% and 17.9% of the patients, respectively. Five year OS and CSS were 91.1% and 98.8%, respectively. Low, intermediate and high risk patients had 5 year CSS of 100%, 99.1% and 98.4%, respectively. Five year PFS for total population, low, intermediate and high risk patients were 95.3%, 96.4%, 97.2% and 93.4%, respectively. Grade 1, 2 and 3 acute gastrointestinal (GI) and genitourinary (GU) toxicities were 12%, 0.7%, 0.4%, and 71.5 %, 14.6%, 0% respectively. Late GI and GU toxicities were 25.2% and 36.5% for grade 1, 1.5% and 13.5% for grade 2 and 0.7% and 1.5% for grade 3, respectively. Significantly less acute GI toxicities were observed in patients with concurrent ADT use compared with no ADT (37.1% vs. 62.9%, p < 0.001). Patients who had GU symptoms requiring medical therapy at baseline or during the radiotherapy developed more frequent grade 2 or higher late GU toxicities (p=0.001 for baseline symptoms and p=0.002 for during radiotherapy by log rank). Patients with anti-coagulation therapy had similar rate of late GI and GU toxicities to patients without anti- VMAT was well tolerated and showed excellent 5 year OS, CSS and PFS for localized prostate cancer. Concurrent ADT use may be associated with less acute GI toxicities. PO-0828 Analysis of the urethro-vesical region for urinary toxicity prediction after prostate radiotherapy T. Lizée 1,2 , E. Mylona 1 , C. Lafond 3 , S. Supiot 4 , O. Acosta 1 , R. De Crevoisier 1,3 1 INSERM U1099 - Université de Rennes 1, Laboratoire Traitement du Signal et de l'Image, Rennes, France 2 Institut de Cancérologie de l'Ouest - Paul Papin, Radiation oncology, Angers, France 3 Centre Eugène Marquis, Radiation oncology, Rennes, France 4 Institut de Cancérologie de l'Ouest - René Gauducheau, Radiation oncology, Nantes, France Purpose or Objective Urinary toxicity after prostate cancer radiotherapy is still poorly understood. Each specific urinary symptom is likely related to the irradiation of specific urinary sub- regions which need to be identified. The objective of the study was to identify urethro-vesical sub-regions potentially implicated in late urinary frequency after prostate cancer radiotherapy. Material and Methods A total of 123 patients, included in a prospective phase III trial (STIC-IGRT P) were analyzed. The patients received IMRT with IGRT for localized prostate cancer at a median dose of 78 Gy (range, 74-80). In addition to the standard manual delineated volumes (prostate and bladder), the following original volumes were generated on the planning CT: a 5 mm diameter urethra (segmented by a multi-atlas-based algorithm; Acosta et al. Radiother Oncol. 2017) divided into 3 equivalent thirds (upper, middle and lower); a basal point defined as the highest central urethral point; a 10 mm sphere around this basal point (Figure 1). Univariate cox model analysis was used to find DVH points as predictor of late urinary frequency (grade ≥ 2 CTCAE V3). coagulation. Conclusion

Conclusion Overall, UI in the first two years following ADV or SALV RT was mild, although a trend toward an increase of the fraction of pts experiencing SUI over time was observed. Slightly higher ICIQ-SF scores at 2 years were observed in the ADV subset. Baseline UI, higher EDQ2 RT doses, TTRT and ADT emerged as the strongest predictors of long- term SUI. PO-0827 Five year follow-up of prostate cancer patients treated with volumetric modulated arc therapy (VMAT) M. Ogita 1 , K. Yamamoto 2 , K. Shiraishi 3 , S. Sawayanagi 1 , H. Yamashita 1 , K. Nakagawa 1 1 University of Tokyo Hospital, Radiology, Tokyo, Japan 2 Self-defencee Forces Central Hospital, Radiology, Tokyo, Japan 3 Teikyo University Hospital, Radiology, Tokyo, Japan Purpose or Objective Volumetric modulated arc therapy (VMAT) is a relatively recently introduced method of intensity-modulated radiotherapy (IMRT) for prostate cancer. We aimed to evaluate its long term efficacy and toxicities. Material and Methods We performed a retrospective analysis using our database. Eligible patients were those with localized prostate cancer treated with VMAT at 70 Gy or higher in our institution. Toxicities were assessed using the Common Terminology Criteria for Adverse Events (CTCAE) version 3.0. Overall survival (OS), cancer specific survival (CSS) and progression free survival (PFS) were calculated using the Kaplan-Meier method and log rank test. Results From August 2008 to December 2012, 274 consecutive prostate cancer patients were treated with VMAT. Prescribed dose of 76 Gy was given to 86.5% of the patients whereas others received 70-72 Gy as per treating physicians’ discretion. Median follow-up was 65.4 months. Median age was 71 years old. Thirty two patients (11.7%), 113 patients (41.2%) and 129 patients (47.1%) had low, intermediate and high risk prostate cancer