ESTRO 36 Abstract Book

S718 ESTRO 36 _______________________________________________________________________________________________

constitute a benchmark for a prospective “mixed beam” trial: a boost with carbon ions followed by a pelvic photon intensity modulated radiotherapy (NCT 02672449, registered at clinicaltrials.gov). Material and Methods We retrospectively reviewed the data of 76 patients treated in our Institution with photon EBRT according to the inclusion criteria of the forthcoming “mixed beam” trial: cT3a and/or serum prostate-specific antigen >20 ng/mL and/or Gleason score of 8-10, cN0 cM0. Toxicity, biochemical and clinical progression-free survival were assessed. Results Seventy-six patients treated between 05/2010 and 12/2014 fulfilled our criteria. Median age, initial PSA and Gleason score were 74.9 years, 26.4 ng/mL and 8, respectively. Prostate and vesicles or prostate and pelvis were irradiated in 46 and 30 patients, respectively, using intensity modulated radiation therapy. Moderate hypofractionation was employed (Fox Chase regimen), with a median dose of 70.2 Gy (2.7 Gy for 26 fractions). In 61 patients (80.3%) androgen deprivation therapy (ADT) was added. The median follow-up was 30.2 months (range 7.2-61.1 months). Biochemical progression was observed in 22 patients (28.9%) after a median time of 20.2 months (range: 5- 58.1) from the end of EBRT. Sixteen patients had clinical progression, always preceded by biochemical progression. Fifty-seven patients (75.0%) are alive with no evidence of disease, 13 patients (17.1%) are alive with clinically evident disease, 6 patients (7.9%) died (3 for PCa). No grade higher than 2 acute and late toxicity, including urinary and rectal complications, was reported. Conclusion Our results suggest that a more aggressive treatment is necessary. Local treatment intensification based on the “mixed beam” approach combining carbon ions, with its known radiobiological advantages, and photons might really represent a promising strategy in the high-risk PCa and it will be investigated with our prospective clinical trial. EP-1340 Comparing dosimetry and toxicity of 5-field IMRT versus VMAT for prostate & pelvic nodal irradiation P. Turner 1 , S. Jain 1 , D. Mitchell 2 , J. Harney 2 , F. Houghton 2 , J. McAleese 2 , D. Stewart 2 , A. Hounsell 1 , D. Irvine 3 , G. Corey 2 , K. Tumelty 2 , K. Thompson 4 , J. O'Sullivan 1 1 Centre for Cancer Research and Cell Biology- Queen's University of Belfast, Advanced Radiotherapy Group, Belfast, United Kingdom 2 Northern Ireland Cancer Centre, Uro-oncology, Belfast, United Kingdom 3 Northern Ireland Cancer Centre, Radiotherapy Physics, Belfast, United Kingdom 4 Queen's University of Belfast, School of Medicine, Belfast, United Kingdom Purpose or Objective There is emerging evidence supporting the use of prostate and pelvic nodal irradiation in high-risk localised prostate cancer. Recent evidence also suggests a role for local prostate irradiation in metastatic prostate cancer. It is therefore timely to assess different methods of delivering pelvic radiotherapy from the point of view of dosimetry

Conclusion Up to October 2016, 42 patients have completed the treatment. More mature results seem to confirm the presented preliminary ones. Our preliminary data show the feasibility of an extremely hypofractionated schedule with concomitant boost on the mpMRI-identified DIL. The higher number of patients expected for the trial and a longer follow-up are needed to confirm these results. The secondary endpoints of the study, namely the evaluation of late toxicity, patient free survival, overall survival, quality of life and pattern of failure will be investigated when more mature follow-up data will be available. EP-1339 Feasibility and efficacy of moderately hypofractionated radiotherapy in high risk prostate cancer G. Marvaso 1 , G. Riva 2 , C. Bassi 2 , C. Fodor 2 , D. Ciardo 2 , D. Zerini 2 , G. Timon 2 , A. Surgo 3 , A. Maucieri 3 , F. Pansini 4 , P. De Marco 5 , F. Cattani 6 , O. De Cobelli 7 , R. Orecchia 8 , B. Jereczek-Fossa 9 1 European Insitute of Oncology, radiation oncologist, Milan, Italy 2 European Institute of Oncology, Radiotherapy, Milan, Italy 3 IEO-University of Milan, Radiotherapy, Milan, Italy 4 European Insitute of Oncology, Medical Physics, Milan, Italy 5 IEO- University of Milan, Medical Physics, Milan, Italy 6 European institute of Oncology, Medical Physics, Milan, Italy 7 IEO- Univesity of Milan, Urology, Milan, Italy 8 IEO, Scientific Direction, Milan, Italy 9 IEO- University of Milan, Radiotherapy, Milan, Italy Purpose or Objective Prostate cancer (PCa) is the second most common male cancer. The prognosis for patients with a diagnosis of high- risk PCa is poor. No consensus exists on the most effective treatment. In the last decade, hadrontherapy with carbon ions has been considered a suitable strategy for high-risk PCa, in terms of the dose delivery with a resulting increased sparing of organs at risk, based on the promising Japanese results and first Italian data from CNAO. The aim of this retrospective study was to identify the biochemical progression-free survival and the toxicity profile of localized high-risk PCa patients treated with external beam radiation therapy (EBRT). These results will

and real world toxicity. Material and Methods

The demographics, disease metrics, RTOG graded toxicity and outcome data for 42 patients receiving prostate and pelvic node radiotherapy in our institution over a 2 year