ESTRO 37 Abstract book

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ESTRO 37

actuarial rates of grade ≥ 2 late GI toxicity were 0.0% – 8.7% (median: 3.8%) and 1.1% at 5-year, respectively. Crude and actuarial rates of grade ≥ 2 late GU toxicity were 0.0% - 66.0% (median: 12.0%) and 7.3% at 5 years. LC was reported in only three studies: 93.7% as crude rate, and 69.0% and 94.9% at 5 years. Crude and actuarial rates of OS were 96.4% and 100% (median: 98.5%) and 91.0% at 10 years and 100% at 5 years. Actuarial rates of bRFS ranged between 83.7% and 92.0% at 1 year, 72.9 % and 83.0% at 2 years, and 74.0% and 94.0% (median: 84.0%), 67.0% and 75.0%, 86.5% at 3, 4 and 5 years, respectively. Conclusion Acute toxicity does not seem to be increased in patients with PCa receiving HFRT after radical prostatectomy (RP). Results in terms of late GU toxicity are conflicting and therefore further prospective studies are needed to clarify this issue before including postoperative HFRT in clinical practice. EP-1562 Phase II“cima” trial on combined, intensified and modulated adjuvant radiotherapy in prostate cancer F. Deodato 1 , G. Siepe 2 , G. Macchia 1 , S. Cilla 3 , M. Ferro 1 , E. Arena 1 , M. Buwenge 2 , M. Ntreta 2 , A. Cortesi 2,4 , A. Arcelli 2,5 , L. Ronchi 2 , R. Vanini 6 , S. Cammelli 2 , T. Wondemagegnhu 7 , V. Valentini 8 , A.G. Morganti 2 1 Radiotherapy Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Campobasso, Italy 2 Radiation Oncology Center, Department of Experimental- Diagnostic and Specialty Medicine - DIMES- University of Bologna, Bologna, Italy 3 Medical Physics Unit, Fondazione di Ricerca e Cura “Giovanni Paolo II”, Campobasso, Italy 4 Radiotherapy Department, Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori IRST, IRCCS, Italy 5 Radiotherapy Department, Ospedale Bellaria, Bologna, Italy 6 Medical Physic Unit, Department of Experimental- Diagnostic and Specialty Medicine - DIMES- University of Bologna S. Orsola-Malpighi Hospital, Bologna, Italy 7 Department of Radiotherapy, Black Lion Hospital, Addis- Ababa, Ethiopia 8 Radiation Oncology Department Gemelli-ART, Fondazione Policlinico Agostino Gemelli- Università Cattolica del S. Cuore, Roma, Italy Purpose or Objective Purpose/Objective. Prostate cancer patients at high risk of loco-regional recurrences may benefit from postoperative radiotherapy (RT) following radical prostatectomy (EORTC trial 22911). However, despite an improvement in biochemical relapse-free survival (bRFS), the risk of recurrences remained high for those patients. We postulated that adjuvant androgen deprivation therapy (ADT), radiation dose escalation, and selective pelvic irradiation for patients at risk for regional failures may improve the outcome. The combined-intensified- modulated-adjuvant (CIMA) as described may improve survival through a reduction of loco-regional and systemic failures. Material and Methods Material/Methods. A phase II trial was designed to test the hypothesis that CIMA treatment may improve 5-year bRFS by 15%. Patients less than 80 years old, with a histological diagnosis of prostate adenocarcinoma without distant metastases, stage pT2-4 N0-1, no previous treatments and an ECOG performance status of 0-2 were

selected. All patients had at least one of these pathologic features: extracapsular extension, positive surgical margins, or seminal vesicle invasion. Radiation dose to the tumor bed ranged from 64.8 to 70.2 Gy. Pelvic lymph nodes were treated to 45 Gy in selected patients at risk of regional failures (57%). Selected patients at risk for distant metastases (69.1%) received hormonal therapy. Results Results. One-hundred-twenty-three patients were enrolled in the study and completed the planned CIMA treatment. At a median follow-up of 67 months (range: 48.0-98.0 months), actuarial 5-year bDFS was 92.9%. Actuarial 5-year local control and metastasis-free survival (MFS) were 98.7% and 96.1%, respectively. Actuarial 5- year overall survival was 95.1%. Actuarial 5-year MFS were 98.8% and 86.8% in patients with Gleason score 7 or less and above 7, respectively (p=0.01). Only 2.4% and 3.3% of patients developed grade 3 acute gastrointestinal (GI) and genitourinary (GU) toxicity, respectively. 5-year survival free from grade ≥ 2 GI and GU toxicity was 96.7% and 88.6%, respectively. Conclusion Conclusions. In selected patients at risk of recurrences following RP, CIMA was well tolerated and improved bRFS. Patients with a high Gleason score (>7) had an increased risk of developing distant metastases despite hormonal therapy. These patients may benefit from chemotherapy in future prospective trials. EP-1563 An offline adaptive strategy for external beam radiotherapy in prostate cancer. C. Pisani 1 , D. Beldì 1 , E. Ferrara 1 , G. Loi 2 , J. Yin 3 , L. Deantonio 1 , E. Mones 4 , M. Krengli 1 1 University Hospital Maggiore della Carità, Radiotherapy, Novara, Italy 2 University Hospital Maggiore della Carità, Medical Physic, Novara, Italy 3 Chengdu hospital, Radiotherapy, Chengdu, China 4 University Hospital Maggiore della Carità, Medical Physics, Novara, Italy Purpose or Objective To develop a new adaptive treatment method for prostate cancer (PCa) radiotherapy (RT), using an off-line strategy to design a patient-specific ITV based on the study of organ motion obtained by serial Cone-Beam CT (CBCT) images and management of the geometrical uncertainties with robust optimization. Material and Methods 20 patients (pts) with intermediate-high PCa treated with radical RT were enrolled in this study. The prescribed dose was 78 Gy to prostate (CTV1) and 60 Gy to prostate plus seminal vesicles (CTV2) delivering 2 Gy/fraction (fr). The CBCTs were acquired according to our IGRT protocol during the first 5 frs, then once a week for the remaining of the treatment. The CBCTs were imported in the Raystation treatment planning system (TPS) and coregistered with the planning CT using the on-line match rigid transformations provided by the OBI system on the treatment unit (Varian Trilogy TX). Then the deformable image registration (DIR) algorithm ANACONDA was applied to propagate the CTV1 and CTV2 volumes from the reference planning CT to the first 5 CBCTs. The reliability of the DIR mapped ROIs was assessed by a radiation oncologist and the contours were used to generate the ITV used to adapt the plan. The original plan was re-optimized using robust algorithm based on the worst scenario optimization assuming an isotropic 5 mm maximum setup error. Then CTV coverage and OAR