ESTRO 36 Abstract Book

S728 ESTRO 36 _______________________________________________________________________________________________

phase 3 trials. However, evidences in post-operative setting are scarce. We report our experience about feasibility and acute toxicity of a moderate hypofractionated intensity modulated radiotherapy (Hypo-IMRT) schedule for prostate cancer (PC) after From October 2015 to July 2016, 23 patients (pts) were included for adjuvant (60,9%) or salvage radiation therapy (39,1%). They were classified with NCCN criteria in: low (2 pts), intermediate (13 pts) and high risk (8 pts). Median age was 63 years (range 55-77 years). Median PSA pretreatment was 0.31ng/mL (range 0.04 – 4.38ng/mL). Pathological characteristics are summarized in Table 1. Two internal gold-fiducial markers were placed transperineally guided by transrectal ultrasound, in every patient before treatment. CTV was countered according to RTOG guidelines and expanded 3 mm posteriorly and 5 mm in all other direction to create the PTV. All patients underwent treatment with IMRT up to a total dose of 62.5Gy in 25fx (2,5Gy/day) in a Novalis linac. Daily verification was performed with IGRT-Exactrac®, and 6D- robotic couch. Six (26%) patients received androgen deprivation. Acute toxicity was assessed according to RTOG/EORTC criteria and was recorded weekly during treatment and one month after radiation therapy. radical prostatectomy. Material and Methods

Gleason score: 6 7(3+4) 7(4+3) 8-10 9% 35% 26% 30% Seminal vesicles invasion: -Yes -No 17% 83% Extracapsular extension: -Yes -No 61% 39% Positive Margin : -Yes -No 48% 52% Perineural invasion: -Yes - No 52% 48% Linfovascular invasion: -Yes -No 22% 78% Results All patients received complete treatment. There were no complications during marker placement. With a median follow-up of 3.7 months (range 1-13 months ), the RTOG/EORTC acute urinary toxicities were grade 1 in 34,7 % and grade 2 in 21,7 %. Neither urinary stress nor incontinence was influenced by radiation therapy. Maximal acute gastrointestinal toxicities were grade 1 in 13%. There was no adverse events ≥ grade 3. Conclusion