ESTRO 38 Abstract book

S847 ESTRO 38

L. Pelari 1 , F. López 1 , G. Caddedu 1 , K. Ytuza 1 , A. Hernández 1 , I. Ciscar 1 , C. Vallejo 1 , M. Martín 1 , S. Sancho 1 , A. Hervás 1 1 Ramón y Cajal Hospital, Radiation Oncology, Madrid, Spain Purpose or Objective To evaluate preliminary clinical results, acute and chronic genitourinary (GU) and gastrointestinal (GI) toxicity of a retrospective cohort of high-risk prostate cancer patients treated with External Beam Radiation Therapy (EBRT) and a boost of High-Dose-Rate Brachytherapy (HDR-BT). Material and Methods Patients with histologically confirmed high risk prostate cancer defined by National Comprehensive Cancer Network (NCCN) risk group were included. Patients received hypofractionated and image-guided EBRT by volumetric IMRT technique to a dose of 37.5 Gy in 15 fractions combined with a single 15 Gy HDR-BT ( 60 Co multi- source) dose (Arm-1) or 60 Gy in 30 fractions combined with a single 9 Gy HDR-BT ( 60 Co multi-source) dose (Arm- 2). All patients assumed androgen deprivation therapy for two years. Biochemical recurrence was defined by Phoenix criteria (PSA concentration superior than nadir plus 2 ng/ml). Acute and chronic toxicity (according to the CTCAE Version 4.0) were collected. Toxicity was considered “acute” if occurred until 3 months after the treatment and “chronic” if occurred after 6 months of the end of the treatment. Results From February 2008 to July 2015, 78 patients were treated by the reported schedules. Median age was 72 years (range 42-83 years). With a median follow-up of 49 months (range 23 –126 months) the median biochemical progression-free survival rates were 91,5% for the 15 Gy HDR group (Arm 1) and 93,8% for the squeme of treatment of 9 Gy HDR (Arm 2). No post-HDR procedure complications were detected in all patients. Arm-1: Acute GU toxicity grade I occurred in 8 patients (50%). No patients developed acute GI toxicity. Chronic GU toxicity grade I occurred in 2 patients (12,5 %). Chronic GI toxicity grade I was observed in 2 patients (12,5 %). No patients developed GU or GI acute or chronic toxicity ≥ GII. Arm-2: Acute GU toxicity grade I occurred in 25 patients (40,3%), grade II in 7 patients (11,3 %) and grade III in 3 patients (4,8 %). Acute GI toxicity grade I were observed in 16 patients (25,8 %). No patient developed GI toxicity ≥ GII. Chronic GU toxicity occurred as follows: grade I in 13 patients (20,9 %), grade II in 4 patients (6,45 %) and grade III in 2 patients (3,22 %). Chronic GI toxicity grade I was observed in 4 patients (6,45%) and grade II in 1 patient (1,6 %). No late gradeIV GU or GI toxicity was detected. Conclusion Hypo-RT combined with HDR-BT produces acceptable acute and chronic toxicity rates with promising outcomes of biochemical control for high risk prostate cancer. Longer term follow-up should be analysed to confirm these data and to compare possible differences between both arms. EP-1570 Stereotactic body radiation therapy for oligometastatic prostate cancer. Our experience. C. García Aguilera 1 , A. Méndez Villamón 1 , I. Guerrero Fernández de Alba 2 , D. Villa Gazulla 3 , A. Miranda Burgos 1 , J.M. Ponce Ortega 1 , M.M. Puertas Valiño 1 , C. Escuín Troncho 1 , B. García Gimeno 1 , M.J. Irún Cuairán 1 , C. Borbonada Martínez 1 , M. Tejedor Gutiérrez 1 1 Hospital Universitario Miguel Servet, Servicio de Oncología Radioterápica, Zaragoza, Spain ; 2 Hospital Universitario Miguel Servet, Servicio de Medicina Preventiva, Zaragoza, Spain ; 3 Hospital Universitario Miguel Servet, Servicio de Física y Protección Radiológica, Zaragoza, Spain

EP-1568 Long-term results of [18F] Fluorocholine PET/CT guided SBRT in patients with prostate cancer F. Pasqualetti 1 , M. Panichi 2 , P. Cocuzza 3 , A. Gonnelli 3 , D. Baldaccini 3 , A. Molinari 3 , M. Cantarella 4 , R. Mattioni 3 , S. Montrone 2 , A. Cristaudo 3 , A. Marciano 5 , R. Zanca 5 , M. Sollini 6 , A. Sainato 2 , P.A. Erba 5 , F. Paiar 3 1 Azienda Ospedaliero Universitaria Pisana, Oncology, Pisa, Italy ; 2 Azienda Ospedaliero Universitaria Pisana, Radiotherapy, Pisa, Italy ; 3 University of Pisa, Radiotherapy, Pisa, Italy ; 4 Casa di Cura Sanrossore, Radiotherapy, Pisa, Italy ; 5 University of Pisa, Nuclear Medicine, Pisa, Italy ; 6 Humanitas Cancer Centre, Nuclear Medicine, Milan, Italy Purpose or Objective Aim : In the last years, functional imaging has given a significant contribution to the clinical decision making of biochemical relapsed prostate cancer (PCa), allowing early diagnosis of metastatic disease with a limited tumor burden, the so-called oligometastatic patients, and driving local therapies like stereotactic body radiotherapy (SBRT). Herby, we present a prospective study aiming to validate the role of [ 18 F]Fluoro-Methyl Choline ([ 18 F]FMCH) PET/CT in the selection of PCa patients suitable for SBRT. Material and Methods Materials and Methods: Patients with biochemical recurrence were screened. Eligible patients were imaged with Endo-rectal Magnetic Resonance to exclude local recurrence inside the prostate bed and [ 18 F]FMCH PET/CT to assess tumor burden. Patients with up to three synchronous active lesions identified by [ 18 F]FMCH PET/CT were enrolled in the present study. All patients were treated with SBRT on all active lesions revealed by [ 18 F]FMCH PET/CT. Systemic therapy free-survival since the [ 18 F]FMCH PET/CT was considered as the primary endpoint. Results Results: 50 patients were included in the present study. Forty-five patients with oligometastatic PCa (castration sensitive in 34 patients, castration-resistant in 11) for a total of 66 lesions (lymph node and bone lesions, in 44 and 22 cases, respectively) were considered evaluable for the present analysis. After SBRT, five patients were lost at follow-up since they started ADT for personal reason. Patients’ median age at the time of study entry was 70 years (range 50-81). The median length between PCa diagnosis and study enrollment was 69 months (range, 2- 180 months). At the time of study entry, Median PSA value was 2,69 ng/mL (range 0.9-27,40). In-field progression was observed in 3 out of 66 irradiated lesions. After the detection of oligorecurrent disease following SBRT, 6 patients underwent further courses of SBRT on the active lesions revealed by [ 18 F]FMCH-PET/CT (two, three, four, five courses respectively in 3,1,1,1 patients). Toxicity higher than grade 2 was not recorded. After a median follow-up of 22.3 months, systemic therapy was started in 24 patients (53,3%). Median systemic therapy free survival was 39.1 months (95%CI6.5-68.6) whereas systemic free survival ratios at 6, 12 and 24-month were 93.5%, 73.9%, and 63.1 %, respectively. At univariate Cox regression analysis, Delta PSA and Gleason Score (GS) demonstrated an impact on systemic therapy free survival (p=0.03 and p<0.001, respectively), being GS higher than 6 related to longer systemic therapy free survival. The Delta PSA remained statistically significant on multivariate analyses while the Gleason Score shows a trend to a statistically significant association (p<0.001 and p=0.18, respectively). Conclusion Conclusion: Based on our findings, [ 18 F]FMCH PET/CT can identify oligometastatic patients suitable for SBRT, resulting in a systemic therapy free survival of 39.1 months. EP-1569 High-dose-rate brachytherapy boost in high- risk prostate cancer: results of two different schemes