ESTRO 36 Abstract Book

S707 ESTRO 36 _______________________________________________________________________________________________

Acute and late toxicity profile was acceptable and is summarized in Table I. Median PSA at the last follow up was 0.09 (0.0-900.0) ng/mL and only 7 pts had ongoing AD. Thirteen pts (11.3%) presented clinical relapse: 2 local, 1 in the mediastinal lymph nodes, 3 combined lymph-nodal (2 mediastinal, 1 para aortic) and bone/visceral metastases, and 7 distant metastases (bone, visceral) only. Twenty-four pts have deceased, but only 3 due to prostate cancer. Five and 7 year actuarial biochemical relapse-free survival (bRFS) was 87% and 80%, respectively(Fig I); corresponding rates of disease-free survival (DFS, accounting for both local and distant failures) were 90% and 84% (Fig. II), of distant metastases -free survival (DMFS) 91% and 89%. overall survival (OS) 89% and 78%, and of cancer specific survival (CSS) 98% and 96%, respectively. Grading/Toxicit y Acute GU Acute rectal Acute bowel Late GU Late GI

extreme dose-escalation, our results suggest that its impact appear to be significantly limited by prophylactic PLN irradiation. EP-1319 “Adjuvant”/ radical radiotherapy in prostate cancer patients with synchronous bone oligometastasis C.L. Deantoni 1 , A. Fodor 1 , C. Sini 2 , B. Noris Chiorda 1 , C. Cozzarini 1 , C. Fiorino 2 , I. Dell'Oca 1 , M. Picchio 3 , E. Incerti 3 , P. Mangili 2 , R. Calandrino 2 , L. Gianolli 3 , N. Di Muzio 1 1 San Raffaele Scientific Institute, Radiotherapy, Milano, Italy 2 San Raffaele Scientific Institute, Medical Physics, Milano, Italy 3 San Raffaele Scientific Institute, Nuclear Medicine, Milano, Italy Purpose or Objective To report the clinical results, obtained in a monoinstitutional experience, in prostate cancer (PCa) pts with synchronous oligometastatic bone disease treated with radical surgery followed by adjuvant radiotherapy with radical intent. Material and Methods From May 2009 to December 2015, 18 oligometastatic (for the purpose of this analysis, no more than 2 bone metastases) PCa pts underwent radical prostatectomy+pelvic/lombo-aortic (LA) lymph-node dissection. After surgery, all pts were simoultaneously treated to bone metastasis (2Gy equivalent dose, EQD2 >40 Gy, α/β=2.2), as well as “adjuvant” RT to the pelvic ± LA nodes (median EQD2 52.2 Gy) and to the seminal vescicle and prostatic bed (median EQD2 60 and 72.4 Gy, respectively, α/β=1.5), in association with androgen deprivation therapy (ADT). Nine pts were treated with conventional fractionation, while 9 with hypofractionated schedule (2,35 Gy/fr in 5 pts or 2,55 Gy/fr in 4 pts). Patients’ characteristics are reported in Table I. Median ( range) age at diagnosis 58.6 (50.5-76.4) years Median (range) iPSA 11.44 (2.40-149.00) ng/ml Median ( range) Gleason Score 9 (7-10) Bone metastasis number 2: 4 Median (range) PSA before RT 0.19 (0.00-75.83) ng/ml Median ( range) follow up after RT 26.3 (4.8-79.4) months Results After a median follow up of 26.3 (4.8-79.4) months, only one patient have deceased owing to prostate cancer progression, while 17 are still alive. Seven pts experienced a relapse, whose characteristics are as follows: 2 biochemical only, 1 in the irradiation field and 4 out of field. At the last follow up, 12 pts were under ADT, of whom one in combination with chemotherapy, while 5 ended ADT and were free from relapse, after a median of 28 (range: 13.3-35) months. Acute toxicity was very mild, with no Grade >2 events, and only 2 serious late events, 1 G3 and 1 G4 urinary (salvage cystectomy for gross haematuria) toxicity, in a patient treated with hypofractionation (2,55 Gy/fr). With respect to bone, no Grade≥1 toxicity were reported. The median biochemical relapse-free survival (bRFS) was 45.3 months. Actuarial 3- and 5-year bRFS was 73% and 37%, respectively, while the distant progression-free survival (DPFS) was 80% and 64%, 1: 14 T Stage pT2: 1 7 9 pT3a: pT3b: pT4: 1 N Stage pN0: 4 pN1: 14

29 (25.2% ) 54 (47.0% ) 31 (27.0% ) 1 (0.8%)

74 (64.4% ) 35 (30.4% ) 6 (5.2%)

63 (54.9% ) 42 (36.5% ) 9 (7.8%) 1 (0.8%)

57 (49.6% ) 37 (32.2% ) 15 (13.0% ) 6 (5.2%)

82 (71.3% ) 17 (14.8% ) 12 (10.4% ) 4 (3.5%)

G0

G1

G2

G3

0

Conclusion HR PCa pts treated with a combination of PLN irradiation, high dose to the prostate delivered with image-guided intensity-modulated moderately hypofractionated RT, (EQD2 for a/b=3 roughly 88Gy), showed excellent 5 and 7 year BRFS and CSS. The main cause of biochemical relapse was regional and/or systemic, mostly outside the pelvis, likely due to pre-existent micro-metastatic disease. While such disease cannot be prevented even by the most