ESTRO 36 Abstract Book

S712 ESTRO 36 2017 _______________________________________________________________________________________________

questionnaire at 3months 6months and then every 6 months. A minimally clinically important change (MCIC) definition was triggered if the EPIC QOL score at each time point decreases > 0.5 SD, where SD is the standard deviation of baseline scores. Results Thirty-three patients (NCCN 6.0% low IR, 45.5% high IR and 48.5% HR) completed the planned treatment with a median follow-up of 13.8 months (IQR 12.1, 18.8). The incidence of worst toxicities is shown in Table 1. The 3 grade 3 GU patients were due to temporary urinary catheterization in the acute period following HDR-BT. Mean (95% SD) EPIC urinary QOL scores were 82.5 (16.5), 83.2 (12.9) and 83.7 (16.3) at baseline, 3 months and 12 months and the bowel scores were 95.9 (3.8), 92.6(8.2) and 90.5 (8.3), respectively. Proportion of patients experiencing MCIC at 3 months and 12 months were 20.8% and 14.3% for urinary domain, 47.8% and 53.9% for bowel domain; respectively. DOMAIN TIMING GRADE 2(%) GRADE 3(%) QOL MCIC(%) GENIOURINARY Acute 45.2% 9.7% 20.8% Late 12.9% 0% 14.3% GASTROINTESTINAL Acute 9.7% 0% 47.8% Late 0% 0% 53.9% Conclusion This novel treatment protocol incorporating MRI dose painted HDR brachytherapy boost and SABR pelvic radiation for intermediate- and high-risk prostate cancer in combination with ADT is feasible and well tolerated in the acute setting. EP-1342 Salvage stereotactic body radiotherapy for lymph node oligorecurrent prostate cancer G. Fanetti 1 , C. Fodor 2 , D. Ciardo 2 , L. Santoro 3 , C.M. Francia 1 , M. Muto 4 , A. Surgo 4 , D. Zerini 2 , G. Marvaso 2 , G. Timon 5 , P. Romanelli 2 , E. Rondi 6 , S. Comi 6 , F. Cattani 6 , D.V. Matei 7 , M. Ferro 7 , G. Musi 7 , F. Nolè 8 , O. De Cobelli 7 , P. Ost 9 , R. Orecchia 10 , B.A. Jereczek-Fossa 1 1 European Institute of Oncology - University of Milan, Department of Radiation Oncology, Milan, Italy 2 European Institute of Oncology, Department of Radiation Oncology, Milan, Italy 3 European Institute of Oncology, Department of Epidemiology and Statistics affiliation at the time of the study, Milan, Italy 4 European Institute of Oncology - University of Milan, Department of Radiation Oncology affiliation at the time of the study, Milan, Italy 5 European Institute of Oncology, Department of Radiation Oncology affiliation at the time of the study, Milan, Italy 6 European Institute of Oncology, Unit of Medical Physics, Milan, Italy 7 European Institute of Oncology, Department of Urology, Milan, Italy 8 European Institute of Oncology, Department of Medical Oncology- Division of Urogenital and Head & Neck Tumours, Milan, Italy 9 Ghent University Hospital, Department of Radiation Oncology, Ghent, Belgium 10 European Institute of Oncology - University of Milan, Department of Medical Imaging and Radiation Science, Milan, Italy Purpose or Objective To evaluate the PSA response, progression free survival (PFS), local control and toxicity of stereotactic body radiotherapy (SBRT) for lymph-node (LN) oligorecurrent prostate cancer. Material and Methods We retrospectively reviewed 95 patients with LN oligorecurrent prostate cancer treated between 05/2012

and 10/2015. We evaluated biochemical response with PSA dosage every 3 months after SBRT: considering the pre-SBRT PSA as reference, a decrease in PSA of more than 10% identified responder patient, whereas an increase of more than 10% identified a biochemical progression. The other cases were classified as PSA stabilization. In case of PSA increase during the follow-up, imaging was performed to evaluate clinical progression. Toxicities were assessed with clinical examination every 6-9 months: acute toxicities were reported in the first 6 months after SBRT. Results A hundred twenty-seven lesions were treated in 95 patients with a median dose of 24 Gy given in 3 fractions. Median pre-SBRT PSA was 3.5 ng/mL. Seventy patients were treated for a single lesion, 25 for 2-4 lesions. In 9 patients SBRT was performed as a re-irradiation. In 35 patients androgen deprivation therapy (ADT) was added to SBRT. Median follow-up was 18.5 months . One patient was not valuable due to short follow-up. Biochemical response, stabilization and progression were observed in 64 (68.1%), 10 (10.6%) and 20 (21.3%) out of 94 patients. In the 57 patients treated with salvage SBRT alone (with no concomitant therapy), biochemical response, stabilization and progression were observed in 38 (66.7%), 9 (15.8%) and 10 (17.5%) cases, respectively. In 17 patients (29.8%) with progressive disease after SBRT, ADT started in a median time of 7.2 months (range 2.4–32.1). Clinical progression was observed in 31 patients (33.0%) after 15 months (median time). In-field progression occurred in 12 lesions (9.4%). 2-year local control and PFS rates were 84% and 30%, respectively (fig. 1-2). Age>75years correlated with better biochemical response rate. Age>75years, concomitant ADT administered up to 12 months and pelvic LN involvement correlated with longer PFS. Acute toxicity included urinary (6 and 1 G1 and G2 events, respectively) and rectal events (1 G1 event). Late toxicity included urinary (2 G1 and 3 G2 events). All toxicities were reported in patients treated for pelvic LN. No toxicity were reported in patients with extra-pelvic LN. At the time of the analysis, 32 (34.0%) patients are alive with no evidence of disease, 60 (63.8%) are alive with clinically evident disease, 2 patients (2.1%) died.